1 //===-- DAGCombiner.cpp - Implement a DAG node combiner -------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Nate Begeman and is distributed under the
6 // University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass combines dag nodes to form fewer, simpler DAG nodes. It can be run
11 // both before and after the DAG is legalized.
13 // FIXME: Missing folds
14 // sdiv, udiv, srem, urem (X, const) where X is an integer can be expanded into
15 // a sequence of multiplies, shifts, and adds. This should be controlled by
16 // some kind of hint from the target that int div is expensive.
17 // various folds of mulh[s,u] by constants such as -1, powers of 2, etc.
19 // FIXME: Should add a corresponding version of fold AND with
20 // ZERO_EXTEND/SIGN_EXTEND by converting them to an ANY_EXTEND node which
23 // FIXME: select C, pow2, pow2 -> something smart
24 // FIXME: trunc(select X, Y, Z) -> select X, trunc(Y), trunc(Z)
25 // FIXME: Dead stores -> nuke
26 // FIXME: shr X, (and Y,31) -> shr X, Y (TRICKY!)
27 // FIXME: mul (x, const) -> shifts + adds
28 // FIXME: undef values
29 // FIXME: make truncate see through SIGN_EXTEND and AND
30 // FIXME: (sra (sra x, c1), c2) -> (sra x, c1+c2)
31 // FIXME: verify that getNode can't return extends with an operand whose type
32 // is >= to that of the extend.
33 // FIXME: divide by zero is currently left unfolded. do we want to turn this
35 // FIXME: select ne (select cc, 1, 0), 0, true, false -> select cc, true, false
36 // FIXME: reassociate (X+C)+Y into (X+Y)+C if the inner expression has one use
38 //===----------------------------------------------------------------------===//
40 #define DEBUG_TYPE "dagcombine"
41 #include "llvm/ADT/Statistic.h"
42 #include "llvm/CodeGen/SelectionDAG.h"
43 #include "llvm/Support/Debug.h"
44 #include "llvm/Support/MathExtras.h"
45 #include "llvm/Target/TargetLowering.h"
51 Statistic<> NodesCombined ("dagcombiner", "Number of dag nodes combined");
58 // Worklist of all of the nodes that need to be simplified.
59 std::vector<SDNode*> WorkList;
61 /// AddUsersToWorkList - When an instruction is simplified, add all users of
62 /// the instruction to the work lists because they might get more simplified
65 void AddUsersToWorkList(SDNode *N) {
66 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
68 WorkList.push_back(*UI);
71 /// removeFromWorkList - remove all instances of N from the worklist.
72 void removeFromWorkList(SDNode *N) {
73 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N),
77 SDOperand CombineTo(SDNode *N, const std::vector<SDOperand> &To) {
79 DEBUG(std::cerr << "\nReplacing "; N->dump();
80 std::cerr << "\nWith: "; To[0].Val->dump();
81 std::cerr << " and " << To.size()-1 << " other values\n");
82 std::vector<SDNode*> NowDead;
83 DAG.ReplaceAllUsesWith(N, To, &NowDead);
85 // Push the new nodes and any users onto the worklist
86 for (unsigned i = 0, e = To.size(); i != e; ++i) {
87 WorkList.push_back(To[i].Val);
88 AddUsersToWorkList(To[i].Val);
91 // Nodes can end up on the worklist more than once. Make sure we do
92 // not process a node that has been replaced.
93 removeFromWorkList(N);
94 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
95 removeFromWorkList(NowDead[i]);
97 // Finally, since the node is now dead, remove it from the graph.
99 return SDOperand(N, 0);
102 SDOperand CombineTo(SDNode *N, SDOperand Res) {
103 std::vector<SDOperand> To;
105 return CombineTo(N, To);
108 SDOperand CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1) {
109 std::vector<SDOperand> To;
112 return CombineTo(N, To);
115 /// visit - call the node-specific routine that knows how to fold each
116 /// particular type of node.
117 SDOperand visit(SDNode *N);
119 // Visitation implementation - Implement dag node combining for different
120 // node types. The semantics are as follows:
122 // SDOperand.Val == 0 - No change was made
123 // SDOperand.Val == N - N was replaced, is dead, and is already handled.
124 // otherwise - N should be replaced by the returned Operand.
126 SDOperand visitTokenFactor(SDNode *N);
127 SDOperand visitADD(SDNode *N);
128 SDOperand visitSUB(SDNode *N);
129 SDOperand visitMUL(SDNode *N);
130 SDOperand visitSDIV(SDNode *N);
131 SDOperand visitUDIV(SDNode *N);
132 SDOperand visitSREM(SDNode *N);
133 SDOperand visitUREM(SDNode *N);
134 SDOperand visitMULHU(SDNode *N);
135 SDOperand visitMULHS(SDNode *N);
136 SDOperand visitAND(SDNode *N);
137 SDOperand visitOR(SDNode *N);
138 SDOperand visitXOR(SDNode *N);
139 SDOperand visitSHL(SDNode *N);
140 SDOperand visitSRA(SDNode *N);
141 SDOperand visitSRL(SDNode *N);
142 SDOperand visitCTLZ(SDNode *N);
143 SDOperand visitCTTZ(SDNode *N);
144 SDOperand visitCTPOP(SDNode *N);
145 SDOperand visitSELECT(SDNode *N);
146 SDOperand visitSELECT_CC(SDNode *N);
147 SDOperand visitSETCC(SDNode *N);
148 SDOperand visitADD_PARTS(SDNode *N);
149 SDOperand visitSUB_PARTS(SDNode *N);
150 SDOperand visitSIGN_EXTEND(SDNode *N);
151 SDOperand visitZERO_EXTEND(SDNode *N);
152 SDOperand visitSIGN_EXTEND_INREG(SDNode *N);
153 SDOperand visitTRUNCATE(SDNode *N);
155 SDOperand visitFADD(SDNode *N);
156 SDOperand visitFSUB(SDNode *N);
157 SDOperand visitFMUL(SDNode *N);
158 SDOperand visitFDIV(SDNode *N);
159 SDOperand visitFREM(SDNode *N);
160 SDOperand visitSINT_TO_FP(SDNode *N);
161 SDOperand visitUINT_TO_FP(SDNode *N);
162 SDOperand visitFP_TO_SINT(SDNode *N);
163 SDOperand visitFP_TO_UINT(SDNode *N);
164 SDOperand visitFP_ROUND(SDNode *N);
165 SDOperand visitFP_ROUND_INREG(SDNode *N);
166 SDOperand visitFP_EXTEND(SDNode *N);
167 SDOperand visitFNEG(SDNode *N);
168 SDOperand visitFABS(SDNode *N);
169 SDOperand visitBRCOND(SDNode *N);
170 SDOperand visitBRCONDTWOWAY(SDNode *N);
171 SDOperand visitBR_CC(SDNode *N);
172 SDOperand visitBRTWOWAY_CC(SDNode *N);
174 SDOperand visitLOAD(SDNode *N);
175 SDOperand visitSTORE(SDNode *N);
177 bool SimplifySelectOps(SDNode *SELECT, SDOperand LHS, SDOperand RHS);
178 SDOperand SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2);
179 SDOperand SimplifySelectCC(SDOperand N0, SDOperand N1, SDOperand N2,
180 SDOperand N3, ISD::CondCode CC);
181 SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1,
182 ISD::CondCode Cond, bool foldBooleans = true);
184 SDOperand BuildSDIV(SDNode *N);
185 SDOperand BuildUDIV(SDNode *N);
187 DAGCombiner(SelectionDAG &D)
188 : DAG(D), TLI(D.getTargetLoweringInfo()), AfterLegalize(false) {}
190 /// Run - runs the dag combiner on all nodes in the work list
191 void Run(bool RunningAfterLegalize);
196 int64_t m; // magic number
197 int64_t s; // shift amount
201 uint64_t m; // magic number
202 int64_t a; // add indicator
203 int64_t s; // shift amount
206 /// magic - calculate the magic numbers required to codegen an integer sdiv as
207 /// a sequence of multiply and shifts. Requires that the divisor not be 0, 1,
209 static ms magic32(int32_t d) {
211 uint32_t ad, anc, delta, q1, r1, q2, r2, t;
212 const uint32_t two31 = 0x80000000U;
216 t = two31 + ((uint32_t)d >> 31);
217 anc = t - 1 - t%ad; // absolute value of nc
218 p = 31; // initialize p
219 q1 = two31/anc; // initialize q1 = 2p/abs(nc)
220 r1 = two31 - q1*anc; // initialize r1 = rem(2p,abs(nc))
221 q2 = two31/ad; // initialize q2 = 2p/abs(d)
222 r2 = two31 - q2*ad; // initialize r2 = rem(2p,abs(d))
225 q1 = 2*q1; // update q1 = 2p/abs(nc)
226 r1 = 2*r1; // update r1 = rem(2p/abs(nc))
227 if (r1 >= anc) { // must be unsigned comparison
231 q2 = 2*q2; // update q2 = 2p/abs(d)
232 r2 = 2*r2; // update r2 = rem(2p/abs(d))
233 if (r2 >= ad) { // must be unsigned comparison
238 } while (q1 < delta || (q1 == delta && r1 == 0));
240 mag.m = (int32_t)(q2 + 1); // make sure to sign extend
241 if (d < 0) mag.m = -mag.m; // resulting magic number
242 mag.s = p - 32; // resulting shift
246 /// magicu - calculate the magic numbers required to codegen an integer udiv as
247 /// a sequence of multiply, add and shifts. Requires that the divisor not be 0.
248 static mu magicu32(uint32_t d) {
250 uint32_t nc, delta, q1, r1, q2, r2;
252 magu.a = 0; // initialize "add" indicator
254 p = 31; // initialize p
255 q1 = 0x80000000/nc; // initialize q1 = 2p/nc
256 r1 = 0x80000000 - q1*nc; // initialize r1 = rem(2p,nc)
257 q2 = 0x7FFFFFFF/d; // initialize q2 = (2p-1)/d
258 r2 = 0x7FFFFFFF - q2*d; // initialize r2 = rem((2p-1),d)
261 if (r1 >= nc - r1 ) {
262 q1 = 2*q1 + 1; // update q1
263 r1 = 2*r1 - nc; // update r1
266 q1 = 2*q1; // update q1
267 r1 = 2*r1; // update r1
269 if (r2 + 1 >= d - r2) {
270 if (q2 >= 0x7FFFFFFF) magu.a = 1;
271 q2 = 2*q2 + 1; // update q2
272 r2 = 2*r2 + 1 - d; // update r2
275 if (q2 >= 0x80000000) magu.a = 1;
276 q2 = 2*q2; // update q2
277 r2 = 2*r2 + 1; // update r2
280 } while (p < 64 && (q1 < delta || (q1 == delta && r1 == 0)));
281 magu.m = q2 + 1; // resulting magic number
282 magu.s = p - 32; // resulting shift
286 /// magic - calculate the magic numbers required to codegen an integer sdiv as
287 /// a sequence of multiply and shifts. Requires that the divisor not be 0, 1,
289 static ms magic64(int64_t d) {
291 uint64_t ad, anc, delta, q1, r1, q2, r2, t;
292 const uint64_t two63 = 9223372036854775808ULL; // 2^63
295 ad = d >= 0 ? d : -d;
296 t = two63 + ((uint64_t)d >> 63);
297 anc = t - 1 - t%ad; // absolute value of nc
298 p = 63; // initialize p
299 q1 = two63/anc; // initialize q1 = 2p/abs(nc)
300 r1 = two63 - q1*anc; // initialize r1 = rem(2p,abs(nc))
301 q2 = two63/ad; // initialize q2 = 2p/abs(d)
302 r2 = two63 - q2*ad; // initialize r2 = rem(2p,abs(d))
305 q1 = 2*q1; // update q1 = 2p/abs(nc)
306 r1 = 2*r1; // update r1 = rem(2p/abs(nc))
307 if (r1 >= anc) { // must be unsigned comparison
311 q2 = 2*q2; // update q2 = 2p/abs(d)
312 r2 = 2*r2; // update r2 = rem(2p/abs(d))
313 if (r2 >= ad) { // must be unsigned comparison
318 } while (q1 < delta || (q1 == delta && r1 == 0));
321 if (d < 0) mag.m = -mag.m; // resulting magic number
322 mag.s = p - 64; // resulting shift
326 /// magicu - calculate the magic numbers required to codegen an integer udiv as
327 /// a sequence of multiply, add and shifts. Requires that the divisor not be 0.
328 static mu magicu64(uint64_t d)
331 uint64_t nc, delta, q1, r1, q2, r2;
333 magu.a = 0; // initialize "add" indicator
335 p = 63; // initialize p
336 q1 = 0x8000000000000000ull/nc; // initialize q1 = 2p/nc
337 r1 = 0x8000000000000000ull - q1*nc; // initialize r1 = rem(2p,nc)
338 q2 = 0x7FFFFFFFFFFFFFFFull/d; // initialize q2 = (2p-1)/d
339 r2 = 0x7FFFFFFFFFFFFFFFull - q2*d; // initialize r2 = rem((2p-1),d)
342 if (r1 >= nc - r1 ) {
343 q1 = 2*q1 + 1; // update q1
344 r1 = 2*r1 - nc; // update r1
347 q1 = 2*q1; // update q1
348 r1 = 2*r1; // update r1
350 if (r2 + 1 >= d - r2) {
351 if (q2 >= 0x7FFFFFFFFFFFFFFFull) magu.a = 1;
352 q2 = 2*q2 + 1; // update q2
353 r2 = 2*r2 + 1 - d; // update r2
356 if (q2 >= 0x8000000000000000ull) magu.a = 1;
357 q2 = 2*q2; // update q2
358 r2 = 2*r2 + 1; // update r2
361 } while (p < 64 && (q1 < delta || (q1 == delta && r1 == 0)));
362 magu.m = q2 + 1; // resulting magic number
363 magu.s = p - 64; // resulting shift
367 /// MaskedValueIsZero - Return true if 'Op & Mask' is known to be zero. We use
368 /// this predicate to simplify operations downstream. Op and Mask are known to
369 /// be the same type.
370 static bool MaskedValueIsZero(const SDOperand &Op, uint64_t Mask,
371 const TargetLowering &TLI) {
373 if (Mask == 0) return true;
375 // If we know the result of a setcc has the top bits zero, use this info.
376 switch (Op.getOpcode()) {
378 return (cast<ConstantSDNode>(Op)->getValue() & Mask) == 0;
380 return ((Mask & 1) == 0) &&
381 TLI.getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult;
383 SrcBits = MVT::getSizeInBits(cast<VTSDNode>(Op.getOperand(3))->getVT());
384 return (Mask & ((1ULL << SrcBits)-1)) == 0; // Returning only the zext bits.
385 case ISD::ZERO_EXTEND:
386 SrcBits = MVT::getSizeInBits(Op.getOperand(0).getValueType());
387 return MaskedValueIsZero(Op.getOperand(0),Mask & ((1ULL << SrcBits)-1),TLI);
388 case ISD::AssertZext:
389 SrcBits = MVT::getSizeInBits(cast<VTSDNode>(Op.getOperand(1))->getVT());
390 return (Mask & ((1ULL << SrcBits)-1)) == 0; // Returning only the zext bits.
392 // If either of the operands has zero bits, the result will too.
393 if (MaskedValueIsZero(Op.getOperand(1), Mask, TLI) ||
394 MaskedValueIsZero(Op.getOperand(0), Mask, TLI))
396 // (X & C1) & C2 == 0 iff C1 & C2 == 0.
397 if (ConstantSDNode *AndRHS = dyn_cast<ConstantSDNode>(Op.getOperand(1)))
398 return MaskedValueIsZero(Op.getOperand(0),AndRHS->getValue() & Mask, TLI);
402 return MaskedValueIsZero(Op.getOperand(0), Mask, TLI) &&
403 MaskedValueIsZero(Op.getOperand(1), Mask, TLI);
405 return MaskedValueIsZero(Op.getOperand(1), Mask, TLI) &&
406 MaskedValueIsZero(Op.getOperand(2), Mask, TLI);
408 return MaskedValueIsZero(Op.getOperand(2), Mask, TLI) &&
409 MaskedValueIsZero(Op.getOperand(3), Mask, TLI);
411 // (ushr X, C1) & C2 == 0 iff X & (C2 << C1) == 0
412 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
413 uint64_t NewVal = Mask << ShAmt->getValue();
414 SrcBits = MVT::getSizeInBits(Op.getValueType());
415 if (SrcBits != 64) NewVal &= (1ULL << SrcBits)-1;
416 return MaskedValueIsZero(Op.getOperand(0), NewVal, TLI);
420 // (ushl X, C1) & C2 == 0 iff X & (C2 >> C1) == 0
421 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
422 uint64_t NewVal = Mask >> ShAmt->getValue();
423 return MaskedValueIsZero(Op.getOperand(0), NewVal, TLI);
427 // (add X, Y) & C == 0 iff (X&C)|(Y&C) == 0 and all bits are low bits.
428 if ((Mask&(Mask+1)) == 0) { // All low bits
429 if (MaskedValueIsZero(Op.getOperand(0), Mask, TLI) &&
430 MaskedValueIsZero(Op.getOperand(1), Mask, TLI))
435 if (ConstantSDNode *CLHS = dyn_cast<ConstantSDNode>(Op.getOperand(0))) {
436 // We know that the top bits of C-X are clear if X contains less bits
437 // than C (i.e. no wrap-around can happen). For example, 20-X is
438 // positive if we can prove that X is >= 0 and < 16.
439 unsigned Bits = MVT::getSizeInBits(CLHS->getValueType(0));
440 if ((CLHS->getValue() & (1 << (Bits-1))) == 0) { // sign bit clear
441 unsigned NLZ = CountLeadingZeros_64(CLHS->getValue()+1);
442 uint64_t MaskV = (1ULL << (63-NLZ))-1;
443 if (MaskedValueIsZero(Op.getOperand(1), ~MaskV, TLI)) {
444 // High bits are clear this value is known to be >= C.
445 unsigned NLZ2 = CountLeadingZeros_64(CLHS->getValue());
446 if ((Mask & ((1ULL << (64-NLZ2))-1)) == 0)
455 // Bit counting instructions can not set the high bits of the result
456 // register. The max number of bits sets depends on the input.
457 return (Mask & (MVT::getSizeInBits(Op.getValueType())*2-1)) == 0;
463 // isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc
464 // that selects between the values 1 and 0, making it equivalent to a setcc.
465 // Also, set the incoming LHS, RHS, and CC references to the appropriate
466 // nodes based on the type of node we are checking. This simplifies life a
467 // bit for the callers.
468 static bool isSetCCEquivalent(SDOperand N, SDOperand &LHS, SDOperand &RHS,
470 if (N.getOpcode() == ISD::SETCC) {
471 LHS = N.getOperand(0);
472 RHS = N.getOperand(1);
473 CC = N.getOperand(2);
476 if (N.getOpcode() == ISD::SELECT_CC &&
477 N.getOperand(2).getOpcode() == ISD::Constant &&
478 N.getOperand(3).getOpcode() == ISD::Constant &&
479 cast<ConstantSDNode>(N.getOperand(2))->getValue() == 1 &&
480 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) {
481 LHS = N.getOperand(0);
482 RHS = N.getOperand(1);
483 CC = N.getOperand(4);
489 // isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only
490 // one use. If this is true, it allows the users to invert the operation for
491 // free when it is profitable to do so.
492 static bool isOneUseSetCC(SDOperand N) {
493 SDOperand N0, N1, N2;
494 if (isSetCCEquivalent(N, N0, N1, N2) && N.Val->hasOneUse())
499 // FIXME: This should probably go in the ISD class rather than being duplicated
501 static bool isCommutativeBinOp(unsigned Opcode) {
507 case ISD::XOR: return true;
508 default: return false; // FIXME: Need commutative info for user ops!
512 void DAGCombiner::Run(bool RunningAfterLegalize) {
513 // set the instance variable, so that the various visit routines may use it.
514 AfterLegalize = RunningAfterLegalize;
516 // Add all the dag nodes to the worklist.
517 WorkList.insert(WorkList.end(), DAG.allnodes_begin(), DAG.allnodes_end());
519 // Create a dummy node (which is not added to allnodes), that adds a reference
520 // to the root node, preventing it from being deleted, and tracking any
521 // changes of the root.
522 HandleSDNode Dummy(DAG.getRoot());
524 // while the worklist isn't empty, inspect the node on the end of it and
525 // try and combine it.
526 while (!WorkList.empty()) {
527 SDNode *N = WorkList.back();
530 // If N has no uses, it is dead. Make sure to revisit all N's operands once
531 // N is deleted from the DAG, since they too may now be dead or may have a
532 // reduced number of uses, allowing other xforms.
533 if (N->use_empty() && N != &Dummy) {
534 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
535 WorkList.push_back(N->getOperand(i).Val);
537 removeFromWorkList(N);
542 SDOperand RV = visit(N);
545 // If we get back the same node we passed in, rather than a new node or
546 // zero, we know that the node must have defined multiple values and
547 // CombineTo was used. Since CombineTo takes care of the worklist
548 // mechanics for us, we have no work to do in this case.
550 DEBUG(std::cerr << "\nReplacing "; N->dump();
551 std::cerr << "\nWith: "; RV.Val->dump();
553 std::vector<SDNode*> NowDead;
554 DAG.ReplaceAllUsesWith(N, std::vector<SDOperand>(1, RV), &NowDead);
556 // Push the new node and any users onto the worklist
557 WorkList.push_back(RV.Val);
558 AddUsersToWorkList(RV.Val);
560 // Nodes can end up on the worklist more than once. Make sure we do
561 // not process a node that has been replaced.
562 removeFromWorkList(N);
563 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
564 removeFromWorkList(NowDead[i]);
566 // Finally, since the node is now dead, remove it from the graph.
572 // If the root changed (e.g. it was a dead load, update the root).
573 DAG.setRoot(Dummy.getValue());
576 SDOperand DAGCombiner::visit(SDNode *N) {
577 switch(N->getOpcode()) {
579 case ISD::TokenFactor: return visitTokenFactor(N);
580 case ISD::ADD: return visitADD(N);
581 case ISD::SUB: return visitSUB(N);
582 case ISD::MUL: return visitMUL(N);
583 case ISD::SDIV: return visitSDIV(N);
584 case ISD::UDIV: return visitUDIV(N);
585 case ISD::SREM: return visitSREM(N);
586 case ISD::UREM: return visitUREM(N);
587 case ISD::MULHU: return visitMULHU(N);
588 case ISD::MULHS: return visitMULHS(N);
589 case ISD::AND: return visitAND(N);
590 case ISD::OR: return visitOR(N);
591 case ISD::XOR: return visitXOR(N);
592 case ISD::SHL: return visitSHL(N);
593 case ISD::SRA: return visitSRA(N);
594 case ISD::SRL: return visitSRL(N);
595 case ISD::CTLZ: return visitCTLZ(N);
596 case ISD::CTTZ: return visitCTTZ(N);
597 case ISD::CTPOP: return visitCTPOP(N);
598 case ISD::SELECT: return visitSELECT(N);
599 case ISD::SELECT_CC: return visitSELECT_CC(N);
600 case ISD::SETCC: return visitSETCC(N);
601 case ISD::ADD_PARTS: return visitADD_PARTS(N);
602 case ISD::SUB_PARTS: return visitSUB_PARTS(N);
603 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N);
604 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N);
605 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N);
606 case ISD::TRUNCATE: return visitTRUNCATE(N);
607 case ISD::FADD: return visitFADD(N);
608 case ISD::FSUB: return visitFSUB(N);
609 case ISD::FMUL: return visitFMUL(N);
610 case ISD::FDIV: return visitFDIV(N);
611 case ISD::FREM: return visitFREM(N);
612 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N);
613 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N);
614 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N);
615 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N);
616 case ISD::FP_ROUND: return visitFP_ROUND(N);
617 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N);
618 case ISD::FP_EXTEND: return visitFP_EXTEND(N);
619 case ISD::FNEG: return visitFNEG(N);
620 case ISD::FABS: return visitFABS(N);
621 case ISD::BRCOND: return visitBRCOND(N);
622 case ISD::BRCONDTWOWAY: return visitBRCONDTWOWAY(N);
623 case ISD::BR_CC: return visitBR_CC(N);
624 case ISD::BRTWOWAY_CC: return visitBRTWOWAY_CC(N);
625 case ISD::LOAD: return visitLOAD(N);
626 case ISD::STORE: return visitSTORE(N);
631 SDOperand DAGCombiner::visitTokenFactor(SDNode *N) {
632 std::vector<SDOperand> Ops;
633 bool Changed = false;
635 // If the token factor has two operands and one is the entry token, replace
636 // the token factor with the other operand.
637 if (N->getNumOperands() == 2) {
638 if (N->getOperand(0).getOpcode() == ISD::EntryToken)
639 return N->getOperand(1);
640 if (N->getOperand(1).getOpcode() == ISD::EntryToken)
641 return N->getOperand(0);
644 // fold (tokenfactor (tokenfactor)) -> tokenfactor
645 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
646 SDOperand Op = N->getOperand(i);
647 if (Op.getOpcode() == ISD::TokenFactor && Op.hasOneUse()) {
649 for (unsigned j = 0, e = Op.getNumOperands(); j != e; ++j)
650 Ops.push_back(Op.getOperand(j));
656 return DAG.getNode(ISD::TokenFactor, MVT::Other, Ops);
660 SDOperand DAGCombiner::visitADD(SDNode *N) {
661 SDOperand N0 = N->getOperand(0);
662 SDOperand N1 = N->getOperand(1);
663 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
664 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
665 MVT::ValueType VT = N0.getValueType();
667 // fold (add c1, c2) -> c1+c2
669 return DAG.getConstant(N0C->getValue() + N1C->getValue(), VT);
670 // canonicalize constant to RHS
672 return DAG.getNode(ISD::ADD, VT, N1, N0);
673 // fold (add x, 0) -> x
674 if (N1C && N1C->isNullValue())
676 // fold (add (add x, c1), c2) -> (add x, c1+c2)
677 if (N1C && N0.getOpcode() == ISD::ADD) {
678 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
679 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
681 return DAG.getNode(ISD::ADD, VT, N0.getOperand(1),
682 DAG.getConstant(N1C->getValue()+N00C->getValue(), VT));
684 return DAG.getNode(ISD::ADD, VT, N0.getOperand(0),
685 DAG.getConstant(N1C->getValue()+N01C->getValue(), VT));
687 // fold ((0-A) + B) -> B-A
688 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) &&
689 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue())
690 return DAG.getNode(ISD::SUB, VT, N1, N0.getOperand(1));
691 // fold (A + (0-B)) -> A-B
692 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) &&
693 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue())
694 return DAG.getNode(ISD::SUB, VT, N0, N1.getOperand(1));
695 // fold (A+(B-A)) -> B
696 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1))
697 return N1.getOperand(0);
701 SDOperand DAGCombiner::visitSUB(SDNode *N) {
702 SDOperand N0 = N->getOperand(0);
703 SDOperand N1 = N->getOperand(1);
704 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
705 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
707 // fold (sub x, x) -> 0
709 return DAG.getConstant(0, N->getValueType(0));
711 // fold (sub c1, c2) -> c1-c2
713 return DAG.getConstant(N0C->getValue() - N1C->getValue(),
715 // fold (sub x, c) -> (add x, -c)
717 return DAG.getNode(ISD::ADD, N0.getValueType(), N0,
718 DAG.getConstant(-N1C->getValue(), N0.getValueType()));
721 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1)
722 return N0.getOperand(1);
724 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1)
725 return N0.getOperand(0);
729 SDOperand DAGCombiner::visitMUL(SDNode *N) {
730 SDOperand N0 = N->getOperand(0);
731 SDOperand N1 = N->getOperand(1);
732 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
733 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
734 MVT::ValueType VT = N0.getValueType();
736 // fold (mul c1, c2) -> c1*c2
738 return DAG.getConstant(N0C->getValue() * N1C->getValue(),
740 // canonicalize constant to RHS
742 return DAG.getNode(ISD::MUL, VT, N1, N0);
743 // fold (mul x, 0) -> 0
744 if (N1C && N1C->isNullValue())
746 // fold (mul x, -1) -> 0-x
747 if (N1C && N1C->isAllOnesValue())
748 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0);
749 // fold (mul x, (1 << c)) -> x << c
750 if (N1C && isPowerOf2_64(N1C->getValue()))
751 return DAG.getNode(ISD::SHL, N->getValueType(0), N0,
752 DAG.getConstant(Log2_64(N1C->getValue()),
753 TLI.getShiftAmountTy()));
754 // fold (mul (mul x, c1), c2) -> (mul x, c1*c2)
755 if (N1C && N0.getOpcode() == ISD::MUL) {
756 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
757 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
759 return DAG.getNode(ISD::MUL, VT, N0.getOperand(1),
760 DAG.getConstant(N1C->getValue()*N00C->getValue(), VT));
762 return DAG.getNode(ISD::MUL, VT, N0.getOperand(0),
763 DAG.getConstant(N1C->getValue()*N01C->getValue(), VT));
768 SDOperand DAGCombiner::visitSDIV(SDNode *N) {
769 SDOperand N0 = N->getOperand(0);
770 SDOperand N1 = N->getOperand(1);
771 MVT::ValueType VT = N->getValueType(0);
772 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
773 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
775 // fold (sdiv c1, c2) -> c1/c2
776 if (N0C && N1C && !N1C->isNullValue())
777 return DAG.getConstant(N0C->getSignExtended() / N1C->getSignExtended(),
779 // fold (sdiv X, 1) -> X
780 if (N1C && N1C->getSignExtended() == 1LL)
782 // fold (sdiv X, -1) -> 0-X
783 if (N1C && N1C->isAllOnesValue())
784 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0);
785 // If we know the sign bits of both operands are zero, strength reduce to a
786 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2
787 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1);
788 if (MaskedValueIsZero(N1, SignBit, TLI) &&
789 MaskedValueIsZero(N0, SignBit, TLI))
790 return DAG.getNode(ISD::UDIV, N1.getValueType(), N0, N1);
791 // fold (sdiv X, pow2) -> (add (sra X, log(pow2)), (srl X, sizeof(X)-1))
792 if (N1C && N1C->getValue() && !TLI.isIntDivCheap() &&
793 (isPowerOf2_64(N1C->getSignExtended()) ||
794 isPowerOf2_64(-N1C->getSignExtended()))) {
795 // If dividing by powers of two is cheap, then don't perform the following
797 if (TLI.isPow2DivCheap())
799 int64_t pow2 = N1C->getSignExtended();
800 int64_t abs2 = pow2 > 0 ? pow2 : -pow2;
801 SDOperand SRL = DAG.getNode(ISD::SRL, VT, N0,
802 DAG.getConstant(MVT::getSizeInBits(VT)-1,
803 TLI.getShiftAmountTy()));
804 WorkList.push_back(SRL.Val);
805 SDOperand SGN = DAG.getNode(ISD::ADD, VT, N0, SRL);
806 WorkList.push_back(SGN.Val);
807 SDOperand SRA = DAG.getNode(ISD::SRA, VT, SGN,
808 DAG.getConstant(Log2_64(abs2),
809 TLI.getShiftAmountTy()));
810 // If we're dividing by a positive value, we're done. Otherwise, we must
811 // negate the result.
814 WorkList.push_back(SRA.Val);
815 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), SRA);
817 // if integer divide is expensive and we satisfy the requirements, emit an
818 // alternate sequence.
819 if (N1C && (N1C->getSignExtended() < -1 || N1C->getSignExtended() > 1) &&
820 !TLI.isIntDivCheap()) {
821 SDOperand Op = BuildSDIV(N);
822 if (Op.Val) return Op;
827 SDOperand DAGCombiner::visitUDIV(SDNode *N) {
828 SDOperand N0 = N->getOperand(0);
829 SDOperand N1 = N->getOperand(1);
830 MVT::ValueType VT = N->getValueType(0);
831 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
832 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
834 // fold (udiv c1, c2) -> c1/c2
835 if (N0C && N1C && !N1C->isNullValue())
836 return DAG.getConstant(N0C->getValue() / N1C->getValue(),
838 // fold (udiv x, (1 << c)) -> x >>u c
839 if (N1C && isPowerOf2_64(N1C->getValue()))
840 return DAG.getNode(ISD::SRL, N->getValueType(0), N0,
841 DAG.getConstant(Log2_64(N1C->getValue()),
842 TLI.getShiftAmountTy()));
843 // fold (udiv x, c) -> alternate
844 if (N1C && N1C->getValue() && !TLI.isIntDivCheap()) {
845 SDOperand Op = BuildUDIV(N);
846 if (Op.Val) return Op;
852 SDOperand DAGCombiner::visitSREM(SDNode *N) {
853 SDOperand N0 = N->getOperand(0);
854 SDOperand N1 = N->getOperand(1);
855 MVT::ValueType VT = N->getValueType(0);
856 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
857 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
859 // fold (srem c1, c2) -> c1%c2
860 if (N0C && N1C && !N1C->isNullValue())
861 return DAG.getConstant(N0C->getSignExtended() % N1C->getSignExtended(),
863 // If we know the sign bits of both operands are zero, strength reduce to a
864 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15
865 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1);
866 if (MaskedValueIsZero(N1, SignBit, TLI) &&
867 MaskedValueIsZero(N0, SignBit, TLI))
868 return DAG.getNode(ISD::UREM, N1.getValueType(), N0, N1);
872 SDOperand DAGCombiner::visitUREM(SDNode *N) {
873 SDOperand N0 = N->getOperand(0);
874 SDOperand N1 = N->getOperand(1);
875 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
876 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
878 // fold (urem c1, c2) -> c1%c2
879 if (N0C && N1C && !N1C->isNullValue())
880 return DAG.getConstant(N0C->getValue() % N1C->getValue(),
882 // fold (urem x, pow2) -> (and x, pow2-1)
883 if (N1C && !N1C->isNullValue() && isPowerOf2_64(N1C->getValue()))
884 return DAG.getNode(ISD::AND, N0.getValueType(), N0,
885 DAG.getConstant(N1C->getValue()-1, N1.getValueType()));
889 SDOperand DAGCombiner::visitMULHS(SDNode *N) {
890 SDOperand N0 = N->getOperand(0);
891 SDOperand N1 = N->getOperand(1);
892 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
894 // fold (mulhs x, 0) -> 0
895 if (N1C && N1C->isNullValue())
897 // fold (mulhs x, 1) -> (sra x, size(x)-1)
898 if (N1C && N1C->getValue() == 1)
899 return DAG.getNode(ISD::SRA, N0.getValueType(), N0,
900 DAG.getConstant(MVT::getSizeInBits(N0.getValueType())-1,
901 TLI.getShiftAmountTy()));
905 SDOperand DAGCombiner::visitMULHU(SDNode *N) {
906 SDOperand N0 = N->getOperand(0);
907 SDOperand N1 = N->getOperand(1);
908 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
910 // fold (mulhu x, 0) -> 0
911 if (N1C && N1C->isNullValue())
913 // fold (mulhu x, 1) -> 0
914 if (N1C && N1C->getValue() == 1)
915 return DAG.getConstant(0, N0.getValueType());
919 SDOperand DAGCombiner::visitAND(SDNode *N) {
920 SDOperand N0 = N->getOperand(0);
921 SDOperand N1 = N->getOperand(1);
922 SDOperand LL, LR, RL, RR, CC0, CC1;
923 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
924 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
925 MVT::ValueType VT = N1.getValueType();
926 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
928 // fold (and c1, c2) -> c1&c2
930 return DAG.getConstant(N0C->getValue() & N1C->getValue(), VT);
931 // canonicalize constant to RHS
933 return DAG.getNode(ISD::AND, VT, N1, N0);
934 // fold (and x, -1) -> x
935 if (N1C && N1C->isAllOnesValue())
937 // if (and x, c) is known to be zero, return 0
938 if (N1C && MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits),TLI))
939 return DAG.getConstant(0, VT);
940 // fold (and x, c) -> x iff (x & ~c) == 0
941 if (N1C && MaskedValueIsZero(N0,~N1C->getValue() & (~0ULL>>(64-OpSizeInBits)),
944 // fold (and (and x, c1), c2) -> (and x, c1^c2)
945 if (N1C && N0.getOpcode() == ISD::AND) {
946 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
947 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
949 return DAG.getNode(ISD::AND, VT, N0.getOperand(1),
950 DAG.getConstant(N1C->getValue()&N00C->getValue(), VT));
952 return DAG.getNode(ISD::AND, VT, N0.getOperand(0),
953 DAG.getConstant(N1C->getValue()&N01C->getValue(), VT));
955 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1)
956 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG) {
957 unsigned ExtendBits =
958 MVT::getSizeInBits(cast<VTSDNode>(N0.getOperand(1))->getVT());
959 if ((N1C->getValue() & (~0ULL << ExtendBits)) == 0)
960 return DAG.getNode(ISD::AND, VT, N0.getOperand(0), N1);
962 // fold (and (or x, 0xFFFF), 0xFF) -> 0xFF
963 if (N0.getOpcode() == ISD::OR && N1C)
964 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
965 if ((ORI->getValue() & N1C->getValue()) == N1C->getValue())
967 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y))
968 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
969 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
970 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
972 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
973 MVT::isInteger(LL.getValueType())) {
974 // fold (X == 0) & (Y == 0) -> (X|Y == 0)
975 if (cast<ConstantSDNode>(LR)->getValue() == 0 && Op1 == ISD::SETEQ) {
976 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
977 WorkList.push_back(ORNode.Val);
978 return DAG.getSetCC(VT, ORNode, LR, Op1);
980 // fold (X == -1) & (Y == -1) -> (X&Y == -1)
981 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) {
982 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
983 WorkList.push_back(ANDNode.Val);
984 return DAG.getSetCC(VT, ANDNode, LR, Op1);
986 // fold (X > -1) & (Y > -1) -> (X|Y > -1)
987 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) {
988 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
989 WorkList.push_back(ORNode.Val);
990 return DAG.getSetCC(VT, ORNode, LR, Op1);
993 // canonicalize equivalent to ll == rl
994 if (LL == RR && LR == RL) {
995 Op1 = ISD::getSetCCSwappedOperands(Op1);
998 if (LL == RL && LR == RR) {
999 bool isInteger = MVT::isInteger(LL.getValueType());
1000 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger);
1001 if (Result != ISD::SETCC_INVALID)
1002 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
1005 // fold (and (zext x), (zext y)) -> (zext (and x, y))
1006 if (N0.getOpcode() == ISD::ZERO_EXTEND &&
1007 N1.getOpcode() == ISD::ZERO_EXTEND &&
1008 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) {
1009 SDOperand ANDNode = DAG.getNode(ISD::AND, N0.getOperand(0).getValueType(),
1010 N0.getOperand(0), N1.getOperand(0));
1011 WorkList.push_back(ANDNode.Val);
1012 return DAG.getNode(ISD::ZERO_EXTEND, VT, ANDNode);
1014 // fold (and (shl/srl x), (shl/srl y)) -> (shl/srl (and x, y))
1015 if (((N0.getOpcode() == ISD::SHL && N1.getOpcode() == ISD::SHL) ||
1016 (N0.getOpcode() == ISD::SRL && N1.getOpcode() == ISD::SRL)) &&
1017 N0.getOperand(1) == N1.getOperand(1)) {
1018 SDOperand ANDNode = DAG.getNode(ISD::AND, N0.getOperand(0).getValueType(),
1019 N0.getOperand(0), N1.getOperand(0));
1020 WorkList.push_back(ANDNode.Val);
1021 return DAG.getNode(N0.getOpcode(), VT, ANDNode, N0.getOperand(1));
1023 // fold (and (sra)) -> (and (srl)) when possible.
1024 if (N0.getOpcode() == ISD::SRA && N0.Val->hasOneUse())
1025 if (ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
1026 // If the RHS of the AND has zeros where the sign bits of the SRA will
1027 // land, turn the SRA into an SRL.
1028 if (MaskedValueIsZero(N1, (~0ULL << (OpSizeInBits-N01C->getValue())) &
1029 (~0ULL>>(64-OpSizeInBits)), TLI)) {
1030 WorkList.push_back(N);
1031 CombineTo(N0.Val, DAG.getNode(ISD::SRL, VT, N0.getOperand(0),
1037 // fold (zext_inreg (extload x)) -> (zextload x)
1038 if (N0.getOpcode() == ISD::EXTLOAD) {
1039 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1040 // If we zero all the possible extended bits, then we can turn this into
1041 // a zextload if we are running before legalize or the operation is legal.
1042 if (MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT), TLI) &&
1043 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) {
1044 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
1045 N0.getOperand(1), N0.getOperand(2),
1047 WorkList.push_back(N);
1048 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1052 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use
1053 if (N0.getOpcode() == ISD::SEXTLOAD && N0.hasOneUse()) {
1054 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1055 // If we zero all the possible extended bits, then we can turn this into
1056 // a zextload if we are running before legalize or the operation is legal.
1057 if (MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT), TLI) &&
1058 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) {
1059 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
1060 N0.getOperand(1), N0.getOperand(2),
1062 WorkList.push_back(N);
1063 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1070 SDOperand DAGCombiner::visitOR(SDNode *N) {
1071 SDOperand N0 = N->getOperand(0);
1072 SDOperand N1 = N->getOperand(1);
1073 SDOperand LL, LR, RL, RR, CC0, CC1;
1074 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1075 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1076 MVT::ValueType VT = N1.getValueType();
1077 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1079 // fold (or c1, c2) -> c1|c2
1081 return DAG.getConstant(N0C->getValue() | N1C->getValue(),
1082 N->getValueType(0));
1083 // canonicalize constant to RHS
1085 return DAG.getNode(ISD::OR, VT, N1, N0);
1086 // fold (or x, 0) -> x
1087 if (N1C && N1C->isNullValue())
1089 // fold (or x, -1) -> -1
1090 if (N1C && N1C->isAllOnesValue())
1092 // fold (or x, c) -> c iff (x & ~c) == 0
1093 if (N1C && MaskedValueIsZero(N0,~N1C->getValue() & (~0ULL>>(64-OpSizeInBits)),
1096 // fold (or (or x, c1), c2) -> (or x, c1|c2)
1097 if (N1C && N0.getOpcode() == ISD::OR) {
1098 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
1099 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
1101 return DAG.getNode(ISD::OR, VT, N0.getOperand(1),
1102 DAG.getConstant(N1C->getValue()|N00C->getValue(), VT));
1104 return DAG.getNode(ISD::OR, VT, N0.getOperand(0),
1105 DAG.getConstant(N1C->getValue()|N01C->getValue(), VT));
1107 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y))
1108 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
1109 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
1110 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
1112 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
1113 MVT::isInteger(LL.getValueType())) {
1114 // fold (X != 0) | (Y != 0) -> (X|Y != 0)
1115 // fold (X < 0) | (Y < 0) -> (X|Y < 0)
1116 if (cast<ConstantSDNode>(LR)->getValue() == 0 &&
1117 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) {
1118 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
1119 WorkList.push_back(ORNode.Val);
1120 return DAG.getSetCC(VT, ORNode, LR, Op1);
1122 // fold (X != -1) | (Y != -1) -> (X&Y != -1)
1123 // fold (X > -1) | (Y > -1) -> (X&Y > -1)
1124 if (cast<ConstantSDNode>(LR)->isAllOnesValue() &&
1125 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) {
1126 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
1127 WorkList.push_back(ANDNode.Val);
1128 return DAG.getSetCC(VT, ANDNode, LR, Op1);
1131 // canonicalize equivalent to ll == rl
1132 if (LL == RR && LR == RL) {
1133 Op1 = ISD::getSetCCSwappedOperands(Op1);
1136 if (LL == RL && LR == RR) {
1137 bool isInteger = MVT::isInteger(LL.getValueType());
1138 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger);
1139 if (Result != ISD::SETCC_INVALID)
1140 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
1143 // fold (or (zext x), (zext y)) -> (zext (or x, y))
1144 if (N0.getOpcode() == ISD::ZERO_EXTEND &&
1145 N1.getOpcode() == ISD::ZERO_EXTEND &&
1146 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) {
1147 SDOperand ORNode = DAG.getNode(ISD::OR, N0.getOperand(0).getValueType(),
1148 N0.getOperand(0), N1.getOperand(0));
1149 WorkList.push_back(ORNode.Val);
1150 return DAG.getNode(ISD::ZERO_EXTEND, VT, ORNode);
1155 SDOperand DAGCombiner::visitXOR(SDNode *N) {
1156 SDOperand N0 = N->getOperand(0);
1157 SDOperand N1 = N->getOperand(1);
1158 SDOperand LHS, RHS, CC;
1159 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1160 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1161 MVT::ValueType VT = N0.getValueType();
1163 // fold (xor c1, c2) -> c1^c2
1165 return DAG.getConstant(N0C->getValue() ^ N1C->getValue(), VT);
1166 // canonicalize constant to RHS
1168 return DAG.getNode(ISD::XOR, VT, N1, N0);
1169 // fold (xor x, 0) -> x
1170 if (N1C && N1C->isNullValue())
1172 // fold !(x cc y) -> (x !cc y)
1173 if (N1C && N1C->getValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) {
1174 bool isInt = MVT::isInteger(LHS.getValueType());
1175 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(),
1177 if (N0.getOpcode() == ISD::SETCC)
1178 return DAG.getSetCC(VT, LHS, RHS, NotCC);
1179 if (N0.getOpcode() == ISD::SELECT_CC)
1180 return DAG.getSelectCC(LHS, RHS, N0.getOperand(2),N0.getOperand(3),NotCC);
1181 assert(0 && "Unhandled SetCC Equivalent!");
1184 // fold !(x or y) -> (!x and !y) iff x or y are setcc
1185 if (N1C && N1C->getValue() == 1 &&
1186 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
1187 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1);
1188 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) {
1189 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
1190 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
1191 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
1192 WorkList.push_back(LHS.Val); WorkList.push_back(RHS.Val);
1193 return DAG.getNode(NewOpcode, VT, LHS, RHS);
1196 // fold !(x or y) -> (!x and !y) iff x or y are constants
1197 if (N1C && N1C->isAllOnesValue() &&
1198 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
1199 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1);
1200 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) {
1201 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
1202 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
1203 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
1204 WorkList.push_back(LHS.Val); WorkList.push_back(RHS.Val);
1205 return DAG.getNode(NewOpcode, VT, LHS, RHS);
1208 // fold (xor (xor x, c1), c2) -> (xor x, c1^c2)
1209 if (N1C && N0.getOpcode() == ISD::XOR) {
1210 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
1211 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
1213 return DAG.getNode(ISD::XOR, VT, N0.getOperand(1),
1214 DAG.getConstant(N1C->getValue()^N00C->getValue(), VT));
1216 return DAG.getNode(ISD::XOR, VT, N0.getOperand(0),
1217 DAG.getConstant(N1C->getValue()^N01C->getValue(), VT));
1219 // fold (xor x, x) -> 0
1221 return DAG.getConstant(0, VT);
1222 // fold (xor (zext x), (zext y)) -> (zext (xor x, y))
1223 if (N0.getOpcode() == ISD::ZERO_EXTEND &&
1224 N1.getOpcode() == ISD::ZERO_EXTEND &&
1225 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) {
1226 SDOperand XORNode = DAG.getNode(ISD::XOR, N0.getOperand(0).getValueType(),
1227 N0.getOperand(0), N1.getOperand(0));
1228 WorkList.push_back(XORNode.Val);
1229 return DAG.getNode(ISD::ZERO_EXTEND, VT, XORNode);
1234 SDOperand DAGCombiner::visitSHL(SDNode *N) {
1235 SDOperand N0 = N->getOperand(0);
1236 SDOperand N1 = N->getOperand(1);
1237 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1238 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1239 MVT::ValueType VT = N0.getValueType();
1240 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1242 // fold (shl c1, c2) -> c1<<c2
1244 return DAG.getConstant(N0C->getValue() << N1C->getValue(), VT);
1245 // fold (shl 0, x) -> 0
1246 if (N0C && N0C->isNullValue())
1248 // fold (shl x, c >= size(x)) -> undef
1249 if (N1C && N1C->getValue() >= OpSizeInBits)
1250 return DAG.getNode(ISD::UNDEF, VT);
1251 // fold (shl x, 0) -> x
1252 if (N1C && N1C->isNullValue())
1254 // if (shl x, c) is known to be zero, return 0
1255 if (N1C && MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits),TLI))
1256 return DAG.getConstant(0, VT);
1257 // fold (shl (shl x, c1), c2) -> 0 or (shl x, c1+c2)
1258 if (N1C && N0.getOpcode() == ISD::SHL &&
1259 N0.getOperand(1).getOpcode() == ISD::Constant) {
1260 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1261 uint64_t c2 = N1C->getValue();
1262 if (c1 + c2 > OpSizeInBits)
1263 return DAG.getConstant(0, VT);
1264 return DAG.getNode(ISD::SHL, VT, N0.getOperand(0),
1265 DAG.getConstant(c1 + c2, N1.getValueType()));
1267 // fold (shl (srl x, c1), c2) -> (shl (and x, -1 << c1), c2-c1) or
1268 // (srl (and x, -1 << c1), c1-c2)
1269 if (N1C && N0.getOpcode() == ISD::SRL &&
1270 N0.getOperand(1).getOpcode() == ISD::Constant) {
1271 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1272 uint64_t c2 = N1C->getValue();
1273 SDOperand Mask = DAG.getNode(ISD::AND, VT, N0.getOperand(0),
1274 DAG.getConstant(~0ULL << c1, VT));
1276 return DAG.getNode(ISD::SHL, VT, Mask,
1277 DAG.getConstant(c2-c1, N1.getValueType()));
1279 return DAG.getNode(ISD::SRL, VT, Mask,
1280 DAG.getConstant(c1-c2, N1.getValueType()));
1282 // fold (shl (sra x, c1), c1) -> (and x, -1 << c1)
1283 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1))
1284 return DAG.getNode(ISD::AND, VT, N0.getOperand(0),
1285 DAG.getConstant(~0ULL << N1C->getValue(), VT));
1289 SDOperand DAGCombiner::visitSRA(SDNode *N) {
1290 SDOperand N0 = N->getOperand(0);
1291 SDOperand N1 = N->getOperand(1);
1292 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1293 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1294 MVT::ValueType VT = N0.getValueType();
1295 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1297 // fold (sra c1, c2) -> c1>>c2
1299 return DAG.getConstant(N0C->getSignExtended() >> N1C->getValue(), VT);
1300 // fold (sra 0, x) -> 0
1301 if (N0C && N0C->isNullValue())
1303 // fold (sra -1, x) -> -1
1304 if (N0C && N0C->isAllOnesValue())
1306 // fold (sra x, c >= size(x)) -> undef
1307 if (N1C && N1C->getValue() >= OpSizeInBits)
1308 return DAG.getNode(ISD::UNDEF, VT);
1309 // fold (sra x, 0) -> x
1310 if (N1C && N1C->isNullValue())
1312 // If the sign bit is known to be zero, switch this to a SRL.
1313 if (MaskedValueIsZero(N0, (1ULL << (OpSizeInBits-1)), TLI))
1314 return DAG.getNode(ISD::SRL, VT, N0, N1);
1318 SDOperand DAGCombiner::visitSRL(SDNode *N) {
1319 SDOperand N0 = N->getOperand(0);
1320 SDOperand N1 = N->getOperand(1);
1321 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1322 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1323 MVT::ValueType VT = N0.getValueType();
1324 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1326 // fold (srl c1, c2) -> c1 >>u c2
1328 return DAG.getConstant(N0C->getValue() >> N1C->getValue(), VT);
1329 // fold (srl 0, x) -> 0
1330 if (N0C && N0C->isNullValue())
1332 // fold (srl x, c >= size(x)) -> undef
1333 if (N1C && N1C->getValue() >= OpSizeInBits)
1334 return DAG.getNode(ISD::UNDEF, VT);
1335 // fold (srl x, 0) -> x
1336 if (N1C && N1C->isNullValue())
1338 // if (srl x, c) is known to be zero, return 0
1339 if (N1C && MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits),TLI))
1340 return DAG.getConstant(0, VT);
1341 // fold (srl (srl x, c1), c2) -> 0 or (srl x, c1+c2)
1342 if (N1C && N0.getOpcode() == ISD::SRL &&
1343 N0.getOperand(1).getOpcode() == ISD::Constant) {
1344 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1345 uint64_t c2 = N1C->getValue();
1346 if (c1 + c2 > OpSizeInBits)
1347 return DAG.getConstant(0, VT);
1348 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0),
1349 DAG.getConstant(c1 + c2, N1.getValueType()));
1354 SDOperand DAGCombiner::visitCTLZ(SDNode *N) {
1355 SDOperand N0 = N->getOperand(0);
1356 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1358 // fold (ctlz c1) -> c2
1360 return DAG.getConstant(CountLeadingZeros_64(N0C->getValue()),
1365 SDOperand DAGCombiner::visitCTTZ(SDNode *N) {
1366 SDOperand N0 = N->getOperand(0);
1367 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1369 // fold (cttz c1) -> c2
1371 return DAG.getConstant(CountTrailingZeros_64(N0C->getValue()),
1376 SDOperand DAGCombiner::visitCTPOP(SDNode *N) {
1377 SDOperand N0 = N->getOperand(0);
1378 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1380 // fold (ctpop c1) -> c2
1382 return DAG.getConstant(CountPopulation_64(N0C->getValue()),
1387 SDOperand DAGCombiner::visitSELECT(SDNode *N) {
1388 SDOperand N0 = N->getOperand(0);
1389 SDOperand N1 = N->getOperand(1);
1390 SDOperand N2 = N->getOperand(2);
1391 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1392 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1393 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
1394 MVT::ValueType VT = N->getValueType(0);
1396 // fold select C, X, X -> X
1399 // fold select true, X, Y -> X
1400 if (N0C && !N0C->isNullValue())
1402 // fold select false, X, Y -> Y
1403 if (N0C && N0C->isNullValue())
1405 // fold select C, 1, X -> C | X
1406 if (MVT::i1 == VT && N1C && N1C->getValue() == 1)
1407 return DAG.getNode(ISD::OR, VT, N0, N2);
1408 // fold select C, 0, X -> ~C & X
1409 // FIXME: this should check for C type == X type, not i1?
1410 if (MVT::i1 == VT && N1C && N1C->isNullValue()) {
1411 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT));
1412 WorkList.push_back(XORNode.Val);
1413 return DAG.getNode(ISD::AND, VT, XORNode, N2);
1415 // fold select C, X, 1 -> ~C | X
1416 if (MVT::i1 == VT && N2C && N2C->getValue() == 1) {
1417 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT));
1418 WorkList.push_back(XORNode.Val);
1419 return DAG.getNode(ISD::OR, VT, XORNode, N1);
1421 // fold select C, X, 0 -> C & X
1422 // FIXME: this should check for C type == X type, not i1?
1423 if (MVT::i1 == VT && N2C && N2C->isNullValue())
1424 return DAG.getNode(ISD::AND, VT, N0, N1);
1425 // fold X ? X : Y --> X ? 1 : Y --> X | Y
1426 if (MVT::i1 == VT && N0 == N1)
1427 return DAG.getNode(ISD::OR, VT, N0, N2);
1428 // fold X ? Y : X --> X ? Y : 0 --> X & Y
1429 if (MVT::i1 == VT && N0 == N2)
1430 return DAG.getNode(ISD::AND, VT, N0, N1);
1432 // If we can fold this based on the true/false value, do so.
1433 if (SimplifySelectOps(N, N1, N2))
1436 // fold selects based on a setcc into other things, such as min/max/abs
1437 if (N0.getOpcode() == ISD::SETCC)
1438 return SimplifySelect(N0, N1, N2);
1442 SDOperand DAGCombiner::visitSELECT_CC(SDNode *N) {
1443 SDOperand N0 = N->getOperand(0);
1444 SDOperand N1 = N->getOperand(1);
1445 SDOperand N2 = N->getOperand(2);
1446 SDOperand N3 = N->getOperand(3);
1447 SDOperand N4 = N->getOperand(4);
1448 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1449 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1450 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
1451 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get();
1453 // Determine if the condition we're dealing with is constant
1454 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false);
1455 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
1457 // fold select_cc lhs, rhs, x, x, cc -> x
1461 // If we can fold this based on the true/false value, do so.
1462 if (SimplifySelectOps(N, N2, N3))
1465 // fold select_cc into other things, such as min/max/abs
1466 return SimplifySelectCC(N0, N1, N2, N3, CC);
1469 SDOperand DAGCombiner::visitSETCC(SDNode *N) {
1470 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1),
1471 cast<CondCodeSDNode>(N->getOperand(2))->get());
1474 SDOperand DAGCombiner::visitADD_PARTS(SDNode *N) {
1475 SDOperand LHSLo = N->getOperand(0);
1476 SDOperand RHSLo = N->getOperand(2);
1477 MVT::ValueType VT = LHSLo.getValueType();
1479 // fold (a_Hi, 0) + (b_Hi, b_Lo) -> (b_Hi + a_Hi, b_Lo)
1480 if (MaskedValueIsZero(LHSLo, (1ULL << MVT::getSizeInBits(VT))-1, TLI)) {
1481 SDOperand Hi = DAG.getNode(ISD::ADD, VT, N->getOperand(1),
1483 WorkList.push_back(Hi.Val);
1484 CombineTo(N, RHSLo, Hi);
1487 // fold (a_Hi, a_Lo) + (b_Hi, 0) -> (a_Hi + b_Hi, a_Lo)
1488 if (MaskedValueIsZero(RHSLo, (1ULL << MVT::getSizeInBits(VT))-1, TLI)) {
1489 SDOperand Hi = DAG.getNode(ISD::ADD, VT, N->getOperand(1),
1491 WorkList.push_back(Hi.Val);
1492 CombineTo(N, LHSLo, Hi);
1498 SDOperand DAGCombiner::visitSUB_PARTS(SDNode *N) {
1499 SDOperand LHSLo = N->getOperand(0);
1500 SDOperand RHSLo = N->getOperand(2);
1501 MVT::ValueType VT = LHSLo.getValueType();
1503 // fold (a_Hi, a_Lo) - (b_Hi, 0) -> (a_Hi - b_Hi, a_Lo)
1504 if (MaskedValueIsZero(RHSLo, (1ULL << MVT::getSizeInBits(VT))-1, TLI)) {
1505 SDOperand Hi = DAG.getNode(ISD::SUB, VT, N->getOperand(1),
1507 WorkList.push_back(Hi.Val);
1508 CombineTo(N, LHSLo, Hi);
1514 SDOperand DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
1515 SDOperand N0 = N->getOperand(0);
1516 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1517 MVT::ValueType VT = N->getValueType(0);
1519 // fold (sext c1) -> c1
1521 return DAG.getConstant(N0C->getSignExtended(), VT);
1522 // fold (sext (sext x)) -> (sext x)
1523 if (N0.getOpcode() == ISD::SIGN_EXTEND)
1524 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0.getOperand(0));
1525 // fold (sext (sextload x)) -> (sextload x)
1526 if (N0.getOpcode() == ISD::SEXTLOAD && VT == N0.getValueType())
1528 // fold (sext (load x)) -> (sextload x)
1529 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse()) {
1530 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1531 N0.getOperand(1), N0.getOperand(2),
1533 WorkList.push_back(N);
1534 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1535 ExtLoad.getValue(1));
1541 SDOperand DAGCombiner::visitZERO_EXTEND(SDNode *N) {
1542 SDOperand N0 = N->getOperand(0);
1543 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1544 MVT::ValueType VT = N->getValueType(0);
1546 // fold (zext c1) -> c1
1548 return DAG.getConstant(N0C->getValue(), VT);
1549 // fold (zext (zext x)) -> (zext x)
1550 if (N0.getOpcode() == ISD::ZERO_EXTEND)
1551 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0.getOperand(0));
1555 SDOperand DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) {
1556 SDOperand N0 = N->getOperand(0);
1557 SDOperand N1 = N->getOperand(1);
1558 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1559 MVT::ValueType VT = N->getValueType(0);
1560 MVT::ValueType EVT = cast<VTSDNode>(N1)->getVT();
1561 unsigned EVTBits = MVT::getSizeInBits(EVT);
1563 // fold (sext_in_reg c1) -> c1
1565 SDOperand Truncate = DAG.getConstant(N0C->getValue(), EVT);
1566 return DAG.getNode(ISD::SIGN_EXTEND, VT, Truncate);
1568 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt1
1569 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
1570 cast<VTSDNode>(N0.getOperand(1))->getVT() <= EVT) {
1573 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2
1574 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
1575 EVT < cast<VTSDNode>(N0.getOperand(1))->getVT()) {
1576 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), N1);
1578 // fold (sext_in_reg (assert_sext x)) -> (assert_sext x)
1579 if (N0.getOpcode() == ISD::AssertSext &&
1580 cast<VTSDNode>(N0.getOperand(1))->getVT() <= EVT) {
1583 // fold (sext_in_reg (sextload x)) -> (sextload x)
1584 if (N0.getOpcode() == ISD::SEXTLOAD &&
1585 cast<VTSDNode>(N0.getOperand(3))->getVT() <= EVT) {
1588 // fold (sext_in_reg (setcc x)) -> setcc x iff (setcc x) == 0 or -1
1589 if (N0.getOpcode() == ISD::SETCC &&
1590 TLI.getSetCCResultContents() ==
1591 TargetLowering::ZeroOrNegativeOneSetCCResult)
1593 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is zero
1594 if (MaskedValueIsZero(N0, 1ULL << (EVTBits-1), TLI))
1595 return DAG.getNode(ISD::AND, N0.getValueType(), N0,
1596 DAG.getConstant(~0ULL >> (64-EVTBits), VT));
1597 // fold (sext_in_reg (srl x)) -> sra x
1598 if (N0.getOpcode() == ISD::SRL &&
1599 N0.getOperand(1).getOpcode() == ISD::Constant &&
1600 cast<ConstantSDNode>(N0.getOperand(1))->getValue() == EVTBits) {
1601 return DAG.getNode(ISD::SRA, N0.getValueType(), N0.getOperand(0),
1604 // fold (sext_inreg (extload x)) -> (sextload x)
1605 if (N0.getOpcode() == ISD::EXTLOAD &&
1606 EVT == cast<VTSDNode>(N0.getOperand(3))->getVT() &&
1607 (!AfterLegalize || TLI.isOperationLegal(ISD::SEXTLOAD, EVT))) {
1608 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1609 N0.getOperand(1), N0.getOperand(2),
1611 WorkList.push_back(N);
1612 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1615 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use
1616 if (N0.getOpcode() == ISD::ZEXTLOAD && N0.hasOneUse() &&
1617 EVT == cast<VTSDNode>(N0.getOperand(3))->getVT() &&
1618 (!AfterLegalize || TLI.isOperationLegal(ISD::SEXTLOAD, EVT))) {
1619 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1620 N0.getOperand(1), N0.getOperand(2),
1622 WorkList.push_back(N);
1623 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1629 SDOperand DAGCombiner::visitTRUNCATE(SDNode *N) {
1630 SDOperand N0 = N->getOperand(0);
1631 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1632 MVT::ValueType VT = N->getValueType(0);
1635 if (N0.getValueType() == N->getValueType(0))
1637 // fold (truncate c1) -> c1
1639 return DAG.getConstant(N0C->getValue(), VT);
1640 // fold (truncate (truncate x)) -> (truncate x)
1641 if (N0.getOpcode() == ISD::TRUNCATE)
1642 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
1643 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x
1644 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND){
1645 if (N0.getValueType() < VT)
1646 // if the source is smaller than the dest, we still need an extend
1647 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0));
1648 else if (N0.getValueType() > VT)
1649 // if the source is larger than the dest, than we just need the truncate
1650 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
1652 // if the source and dest are the same type, we can drop both the extend
1654 return N0.getOperand(0);
1656 // fold (truncate (load x)) -> (smaller load x)
1657 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse()) {
1658 assert(MVT::getSizeInBits(N0.getValueType()) > MVT::getSizeInBits(VT) &&
1659 "Cannot truncate to larger type!");
1660 MVT::ValueType PtrType = N0.getOperand(1).getValueType();
1661 // For big endian targets, we need to add an offset to the pointer to load
1662 // the correct bytes. For little endian systems, we merely need to read
1663 // fewer bytes from the same pointer.
1665 (MVT::getSizeInBits(N0.getValueType()) - MVT::getSizeInBits(VT)) / 8;
1666 SDOperand NewPtr = TLI.isLittleEndian() ? N0.getOperand(1) :
1667 DAG.getNode(ISD::ADD, PtrType, N0.getOperand(1),
1668 DAG.getConstant(PtrOff, PtrType));
1669 WorkList.push_back(NewPtr.Val);
1670 SDOperand Load = DAG.getLoad(VT, N0.getOperand(0), NewPtr,N0.getOperand(2));
1671 WorkList.push_back(N);
1672 CombineTo(N0.Val, Load, Load.getValue(1));
1678 SDOperand DAGCombiner::visitFADD(SDNode *N) {
1679 SDOperand N0 = N->getOperand(0);
1680 SDOperand N1 = N->getOperand(1);
1681 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
1682 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
1683 MVT::ValueType VT = N->getValueType(0);
1685 // fold (fadd c1, c2) -> c1+c2
1687 return DAG.getConstantFP(N0CFP->getValue() + N1CFP->getValue(), VT);
1688 // canonicalize constant to RHS
1689 if (N0CFP && !N1CFP)
1690 return DAG.getNode(ISD::FADD, VT, N1, N0);
1691 // fold (A + (-B)) -> A-B
1692 if (N1.getOpcode() == ISD::FNEG)
1693 return DAG.getNode(ISD::FSUB, VT, N0, N1.getOperand(0));
1694 // fold ((-A) + B) -> B-A
1695 if (N0.getOpcode() == ISD::FNEG)
1696 return DAG.getNode(ISD::FSUB, VT, N1, N0.getOperand(0));
1700 SDOperand DAGCombiner::visitFSUB(SDNode *N) {
1701 SDOperand N0 = N->getOperand(0);
1702 SDOperand N1 = N->getOperand(1);
1703 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
1704 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
1705 MVT::ValueType VT = N->getValueType(0);
1707 // fold (fsub c1, c2) -> c1-c2
1709 return DAG.getConstantFP(N0CFP->getValue() - N1CFP->getValue(), VT);
1710 // fold (A-(-B)) -> A+B
1711 if (N1.getOpcode() == ISD::FNEG)
1712 return DAG.getNode(ISD::FADD, N0.getValueType(), N0, N1.getOperand(0));
1716 SDOperand DAGCombiner::visitFMUL(SDNode *N) {
1717 SDOperand N0 = N->getOperand(0);
1718 SDOperand N1 = N->getOperand(1);
1719 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
1720 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
1721 MVT::ValueType VT = N->getValueType(0);
1723 // fold (fmul c1, c2) -> c1*c2
1725 return DAG.getConstantFP(N0CFP->getValue() * N1CFP->getValue(), VT);
1726 // canonicalize constant to RHS
1727 if (N0CFP && !N1CFP)
1728 return DAG.getNode(ISD::FMUL, VT, N1, N0);
1729 // fold (fmul X, 2.0) -> (fadd X, X)
1730 if (N1CFP && N1CFP->isExactlyValue(+2.0))
1731 return DAG.getNode(ISD::FADD, VT, N0, N0);
1735 SDOperand DAGCombiner::visitFDIV(SDNode *N) {
1736 SDOperand N0 = N->getOperand(0);
1737 SDOperand N1 = N->getOperand(1);
1738 MVT::ValueType VT = N->getValueType(0);
1740 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0))
1741 if (ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1)) {
1742 // fold floating point (fdiv c1, c2)
1743 return DAG.getConstantFP(N0CFP->getValue() / N1CFP->getValue(), VT);
1748 SDOperand DAGCombiner::visitFREM(SDNode *N) {
1749 SDOperand N0 = N->getOperand(0);
1750 SDOperand N1 = N->getOperand(1);
1751 MVT::ValueType VT = N->getValueType(0);
1753 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0))
1754 if (ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1)) {
1755 // fold floating point (frem c1, c2) -> fmod(c1, c2)
1756 return DAG.getConstantFP(fmod(N0CFP->getValue(),N1CFP->getValue()), VT);
1762 SDOperand DAGCombiner::visitSINT_TO_FP(SDNode *N) {
1763 SDOperand N0 = N->getOperand(0);
1764 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1766 // fold (sint_to_fp c1) -> c1fp
1768 return DAG.getConstantFP(N0C->getSignExtended(), N->getValueType(0));
1772 SDOperand DAGCombiner::visitUINT_TO_FP(SDNode *N) {
1773 SDOperand N0 = N->getOperand(0);
1774 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1776 // fold (uint_to_fp c1) -> c1fp
1778 return DAG.getConstantFP(N0C->getValue(), N->getValueType(0));
1782 SDOperand DAGCombiner::visitFP_TO_SINT(SDNode *N) {
1783 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1785 // fold (fp_to_sint c1fp) -> c1
1787 return DAG.getConstant((int64_t)N0CFP->getValue(), N->getValueType(0));
1791 SDOperand DAGCombiner::visitFP_TO_UINT(SDNode *N) {
1792 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1794 // fold (fp_to_uint c1fp) -> c1
1796 return DAG.getConstant((uint64_t)N0CFP->getValue(), N->getValueType(0));
1800 SDOperand DAGCombiner::visitFP_ROUND(SDNode *N) {
1801 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1803 // fold (fp_round c1fp) -> c1fp
1805 return DAG.getConstantFP(N0CFP->getValue(), N->getValueType(0));
1809 SDOperand DAGCombiner::visitFP_ROUND_INREG(SDNode *N) {
1810 SDOperand N0 = N->getOperand(0);
1811 MVT::ValueType VT = N->getValueType(0);
1812 MVT::ValueType EVT = cast<VTSDNode>(N->getOperand(1))->getVT();
1813 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
1815 // fold (fp_round_inreg c1fp) -> c1fp
1817 SDOperand Round = DAG.getConstantFP(N0CFP->getValue(), EVT);
1818 return DAG.getNode(ISD::FP_EXTEND, VT, Round);
1823 SDOperand DAGCombiner::visitFP_EXTEND(SDNode *N) {
1824 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1826 // fold (fp_extend c1fp) -> c1fp
1828 return DAG.getConstantFP(N0CFP->getValue(), N->getValueType(0));
1832 SDOperand DAGCombiner::visitFNEG(SDNode *N) {
1833 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1834 // fold (neg c1) -> -c1
1836 return DAG.getConstantFP(-N0CFP->getValue(), N->getValueType(0));
1837 // fold (neg (sub x, y)) -> (sub y, x)
1838 if (N->getOperand(0).getOpcode() == ISD::SUB)
1839 return DAG.getNode(ISD::SUB, N->getValueType(0), N->getOperand(1),
1841 // fold (neg (neg x)) -> x
1842 if (N->getOperand(0).getOpcode() == ISD::FNEG)
1843 return N->getOperand(0).getOperand(0);
1847 SDOperand DAGCombiner::visitFABS(SDNode *N) {
1848 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1849 // fold (fabs c1) -> fabs(c1)
1851 return DAG.getConstantFP(fabs(N0CFP->getValue()), N->getValueType(0));
1852 // fold (fabs (fabs x)) -> (fabs x)
1853 if (N->getOperand(0).getOpcode() == ISD::FABS)
1854 return N->getOperand(0);
1855 // fold (fabs (fneg x)) -> (fabs x)
1856 if (N->getOperand(0).getOpcode() == ISD::FNEG)
1857 return DAG.getNode(ISD::FABS, N->getValueType(0),
1858 N->getOperand(0).getOperand(0));
1862 SDOperand DAGCombiner::visitBRCOND(SDNode *N) {
1863 SDOperand Chain = N->getOperand(0);
1864 SDOperand N1 = N->getOperand(1);
1865 SDOperand N2 = N->getOperand(2);
1866 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1868 // never taken branch, fold to chain
1869 if (N1C && N1C->isNullValue())
1871 // unconditional branch
1872 if (N1C && N1C->getValue() == 1)
1873 return DAG.getNode(ISD::BR, MVT::Other, Chain, N2);
1877 SDOperand DAGCombiner::visitBRCONDTWOWAY(SDNode *N) {
1878 SDOperand Chain = N->getOperand(0);
1879 SDOperand N1 = N->getOperand(1);
1880 SDOperand N2 = N->getOperand(2);
1881 SDOperand N3 = N->getOperand(3);
1882 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1884 // unconditional branch to true mbb
1885 if (N1C && N1C->getValue() == 1)
1886 return DAG.getNode(ISD::BR, MVT::Other, Chain, N2);
1887 // unconditional branch to false mbb
1888 if (N1C && N1C->isNullValue())
1889 return DAG.getNode(ISD::BR, MVT::Other, Chain, N3);
1893 // Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB.
1895 SDOperand DAGCombiner::visitBR_CC(SDNode *N) {
1896 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1));
1897 SDOperand CondLHS = N->getOperand(2), CondRHS = N->getOperand(3);
1899 // Use SimplifySetCC to simplify SETCC's.
1900 SDOperand Simp = SimplifySetCC(MVT::i1, CondLHS, CondRHS, CC->get(), false);
1901 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(Simp.Val);
1903 // fold br_cc true, dest -> br dest (unconditional branch)
1904 if (SCCC && SCCC->getValue())
1905 return DAG.getNode(ISD::BR, MVT::Other, N->getOperand(0),
1907 // fold br_cc false, dest -> unconditional fall through
1908 if (SCCC && SCCC->isNullValue())
1909 return N->getOperand(0);
1910 // fold to a simpler setcc
1911 if (Simp.Val && Simp.getOpcode() == ISD::SETCC)
1912 return DAG.getNode(ISD::BR_CC, MVT::Other, N->getOperand(0),
1913 Simp.getOperand(2), Simp.getOperand(0),
1914 Simp.getOperand(1), N->getOperand(4));
1918 SDOperand DAGCombiner::visitBRTWOWAY_CC(SDNode *N) {
1919 SDOperand Chain = N->getOperand(0);
1920 SDOperand CCN = N->getOperand(1);
1921 SDOperand LHS = N->getOperand(2);
1922 SDOperand RHS = N->getOperand(3);
1923 SDOperand N4 = N->getOperand(4);
1924 SDOperand N5 = N->getOperand(5);
1926 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), LHS, RHS,
1927 cast<CondCodeSDNode>(CCN)->get(), false);
1928 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
1930 // fold select_cc lhs, rhs, x, x, cc -> x
1932 return DAG.getNode(ISD::BR, MVT::Other, Chain, N4);
1933 // fold select_cc true, x, y -> x
1934 if (SCCC && SCCC->getValue())
1935 return DAG.getNode(ISD::BR, MVT::Other, Chain, N4);
1936 // fold select_cc false, x, y -> y
1937 if (SCCC && SCCC->isNullValue())
1938 return DAG.getNode(ISD::BR, MVT::Other, Chain, N5);
1939 // fold to a simpler setcc
1940 if (SCC.Val && SCC.getOpcode() == ISD::SETCC)
1941 return DAG.getBR2Way_CC(Chain, SCC.getOperand(2), SCC.getOperand(0),
1942 SCC.getOperand(1), N4, N5);
1946 SDOperand DAGCombiner::visitLOAD(SDNode *N) {
1947 SDOperand Chain = N->getOperand(0);
1948 SDOperand Ptr = N->getOperand(1);
1949 SDOperand SrcValue = N->getOperand(2);
1951 // If this load is directly stored, replace the load value with the stored
1953 // TODO: Handle store large -> read small portion.
1954 // TODO: Handle TRUNCSTORE/EXTLOAD
1955 if (Chain.getOpcode() == ISD::STORE && Chain.getOperand(2) == Ptr &&
1956 Chain.getOperand(1).getValueType() == N->getValueType(0))
1957 return CombineTo(N, Chain.getOperand(1), Chain);
1962 SDOperand DAGCombiner::visitSTORE(SDNode *N) {
1963 SDOperand Chain = N->getOperand(0);
1964 SDOperand Value = N->getOperand(1);
1965 SDOperand Ptr = N->getOperand(2);
1966 SDOperand SrcValue = N->getOperand(3);
1968 // If this is a store that kills a previous store, remove the previous store.
1969 if (Chain.getOpcode() == ISD::STORE && Chain.getOperand(2) == Ptr &&
1970 Chain.Val->hasOneUse() /* Avoid introducing DAG cycles */) {
1971 // Create a new store of Value that replaces both stores.
1972 SDNode *PrevStore = Chain.Val;
1973 if (PrevStore->getOperand(1) == Value) // Same value multiply stored.
1975 SDOperand NewStore = DAG.getNode(ISD::STORE, MVT::Other,
1976 PrevStore->getOperand(0), Value, Ptr,
1978 CombineTo(N, NewStore); // Nuke this store.
1979 CombineTo(PrevStore, NewStore); // Nuke the previous store.
1980 return SDOperand(N, 0);
1986 SDOperand DAGCombiner::SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2){
1987 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!");
1989 SDOperand SCC = SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), N1, N2,
1990 cast<CondCodeSDNode>(N0.getOperand(2))->get());
1991 // If we got a simplified select_cc node back from SimplifySelectCC, then
1992 // break it down into a new SETCC node, and a new SELECT node, and then return
1993 // the SELECT node, since we were called with a SELECT node.
1995 // Check to see if we got a select_cc back (to turn into setcc/select).
1996 // Otherwise, just return whatever node we got back, like fabs.
1997 if (SCC.getOpcode() == ISD::SELECT_CC) {
1998 SDOperand SETCC = DAG.getNode(ISD::SETCC, N0.getValueType(),
1999 SCC.getOperand(0), SCC.getOperand(1),
2001 WorkList.push_back(SETCC.Val);
2002 return DAG.getNode(ISD::SELECT, SCC.getValueType(), SCC.getOperand(2),
2003 SCC.getOperand(3), SETCC);
2010 /// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS
2011 /// are the two values being selected between, see if we can simplify the
2014 bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDOperand LHS,
2017 // If this is a select from two identical things, try to pull the operation
2018 // through the select.
2019 if (LHS.getOpcode() == RHS.getOpcode() && LHS.hasOneUse() && RHS.hasOneUse()){
2021 std::cerr << "SELECT: ["; LHS.Val->dump();
2022 std::cerr << "] ["; RHS.Val->dump();
2026 // If this is a load and the token chain is identical, replace the select
2027 // of two loads with a load through a select of the address to load from.
2028 // This triggers in things like "select bool X, 10.0, 123.0" after the FP
2029 // constants have been dropped into the constant pool.
2030 if ((LHS.getOpcode() == ISD::LOAD ||
2031 LHS.getOpcode() == ISD::EXTLOAD ||
2032 LHS.getOpcode() == ISD::ZEXTLOAD ||
2033 LHS.getOpcode() == ISD::SEXTLOAD) &&
2034 // Token chains must be identical.
2035 LHS.getOperand(0) == RHS.getOperand(0) &&
2036 // If this is an EXTLOAD, the VT's must match.
2037 (LHS.getOpcode() == ISD::LOAD ||
2038 LHS.getOperand(3) == RHS.getOperand(3))) {
2039 // FIXME: this conflates two src values, discarding one. This is not
2040 // the right thing to do, but nothing uses srcvalues now. When they do,
2041 // turn SrcValue into a list of locations.
2043 if (TheSelect->getOpcode() == ISD::SELECT)
2044 Addr = DAG.getNode(ISD::SELECT, LHS.getOperand(1).getValueType(),
2045 TheSelect->getOperand(0), LHS.getOperand(1),
2048 Addr = DAG.getNode(ISD::SELECT_CC, LHS.getOperand(1).getValueType(),
2049 TheSelect->getOperand(0),
2050 TheSelect->getOperand(1),
2051 LHS.getOperand(1), RHS.getOperand(1),
2052 TheSelect->getOperand(4));
2055 if (LHS.getOpcode() == ISD::LOAD)
2056 Load = DAG.getLoad(TheSelect->getValueType(0), LHS.getOperand(0),
2057 Addr, LHS.getOperand(2));
2059 Load = DAG.getExtLoad(LHS.getOpcode(), TheSelect->getValueType(0),
2060 LHS.getOperand(0), Addr, LHS.getOperand(2),
2061 cast<VTSDNode>(LHS.getOperand(3))->getVT());
2062 // Users of the select now use the result of the load.
2063 CombineTo(TheSelect, Load);
2065 // Users of the old loads now use the new load's chain. We know the
2066 // old-load value is dead now.
2067 CombineTo(LHS.Val, Load.getValue(0), Load.getValue(1));
2068 CombineTo(RHS.Val, Load.getValue(0), Load.getValue(1));
2076 SDOperand DAGCombiner::SimplifySelectCC(SDOperand N0, SDOperand N1,
2077 SDOperand N2, SDOperand N3,
2080 MVT::ValueType VT = N2.getValueType();
2081 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
2082 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
2083 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.Val);
2084 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.Val);
2086 // Determine if the condition we're dealing with is constant
2087 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false);
2088 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
2090 // fold select_cc true, x, y -> x
2091 if (SCCC && SCCC->getValue())
2093 // fold select_cc false, x, y -> y
2094 if (SCCC && SCCC->getValue() == 0)
2097 // Check to see if we can simplify the select into an fabs node
2098 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) {
2099 // Allow either -0.0 or 0.0
2100 if (CFP->getValue() == 0.0) {
2101 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs
2102 if ((CC == ISD::SETGE || CC == ISD::SETGT) &&
2103 N0 == N2 && N3.getOpcode() == ISD::FNEG &&
2104 N2 == N3.getOperand(0))
2105 return DAG.getNode(ISD::FABS, VT, N0);
2107 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs
2108 if ((CC == ISD::SETLT || CC == ISD::SETLE) &&
2109 N0 == N3 && N2.getOpcode() == ISD::FNEG &&
2110 N2.getOperand(0) == N3)
2111 return DAG.getNode(ISD::FABS, VT, N3);
2115 // Check to see if we can perform the "gzip trick", transforming
2116 // select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A
2117 if (N1C && N1C->isNullValue() && N3C && N3C->isNullValue() &&
2118 MVT::isInteger(N0.getValueType()) &&
2119 MVT::isInteger(N2.getValueType()) && CC == ISD::SETLT) {
2120 MVT::ValueType XType = N0.getValueType();
2121 MVT::ValueType AType = N2.getValueType();
2122 if (XType >= AType) {
2123 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a
2124 // single-bit constant.
2125 if (N2C && ((N2C->getValue() & (N2C->getValue()-1)) == 0)) {
2126 unsigned ShCtV = Log2_64(N2C->getValue());
2127 ShCtV = MVT::getSizeInBits(XType)-ShCtV-1;
2128 SDOperand ShCt = DAG.getConstant(ShCtV, TLI.getShiftAmountTy());
2129 SDOperand Shift = DAG.getNode(ISD::SRL, XType, N0, ShCt);
2130 WorkList.push_back(Shift.Val);
2131 if (XType > AType) {
2132 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
2133 WorkList.push_back(Shift.Val);
2135 return DAG.getNode(ISD::AND, AType, Shift, N2);
2137 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0,
2138 DAG.getConstant(MVT::getSizeInBits(XType)-1,
2139 TLI.getShiftAmountTy()));
2140 WorkList.push_back(Shift.Val);
2141 if (XType > AType) {
2142 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
2143 WorkList.push_back(Shift.Val);
2145 return DAG.getNode(ISD::AND, AType, Shift, N2);
2149 // fold select C, 16, 0 -> shl C, 4
2150 if (N2C && N3C && N3C->isNullValue() && isPowerOf2_64(N2C->getValue()) &&
2151 TLI.getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult) {
2152 // Get a SetCC of the condition
2153 // FIXME: Should probably make sure that setcc is legal if we ever have a
2154 // target where it isn't.
2155 SDOperand Temp, SCC = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC);
2156 WorkList.push_back(SCC.Val);
2157 // cast from setcc result type to select result type
2159 Temp = DAG.getZeroExtendInReg(SCC, N2.getValueType());
2161 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC);
2162 WorkList.push_back(Temp.Val);
2163 // shl setcc result by log2 n2c
2164 return DAG.getNode(ISD::SHL, N2.getValueType(), Temp,
2165 DAG.getConstant(Log2_64(N2C->getValue()),
2166 TLI.getShiftAmountTy()));
2169 // Check to see if this is the equivalent of setcc
2170 // FIXME: Turn all of these into setcc if setcc if setcc is legal
2171 // otherwise, go ahead with the folds.
2172 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getValue() == 1ULL)) {
2173 MVT::ValueType XType = N0.getValueType();
2174 if (TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultTy())) {
2175 SDOperand Res = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC);
2176 if (Res.getValueType() != VT)
2177 Res = DAG.getNode(ISD::ZERO_EXTEND, VT, Res);
2181 // seteq X, 0 -> srl (ctlz X, log2(size(X)))
2182 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ &&
2183 TLI.isOperationLegal(ISD::CTLZ, XType)) {
2184 SDOperand Ctlz = DAG.getNode(ISD::CTLZ, XType, N0);
2185 return DAG.getNode(ISD::SRL, XType, Ctlz,
2186 DAG.getConstant(Log2_32(MVT::getSizeInBits(XType)),
2187 TLI.getShiftAmountTy()));
2189 // setgt X, 0 -> srl (and (-X, ~X), size(X)-1)
2190 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) {
2191 SDOperand NegN0 = DAG.getNode(ISD::SUB, XType, DAG.getConstant(0, XType),
2193 SDOperand NotN0 = DAG.getNode(ISD::XOR, XType, N0,
2194 DAG.getConstant(~0ULL, XType));
2195 return DAG.getNode(ISD::SRL, XType,
2196 DAG.getNode(ISD::AND, XType, NegN0, NotN0),
2197 DAG.getConstant(MVT::getSizeInBits(XType)-1,
2198 TLI.getShiftAmountTy()));
2200 // setgt X, -1 -> xor (srl (X, size(X)-1), 1)
2201 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) {
2202 SDOperand Sign = DAG.getNode(ISD::SRL, XType, N0,
2203 DAG.getConstant(MVT::getSizeInBits(XType)-1,
2204 TLI.getShiftAmountTy()));
2205 return DAG.getNode(ISD::XOR, XType, Sign, DAG.getConstant(1, XType));
2209 // Check to see if this is an integer abs. select_cc setl[te] X, 0, -X, X ->
2210 // Y = sra (X, size(X)-1); xor (add (X, Y), Y)
2211 if (N1C && N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE) &&
2212 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1)) {
2213 if (ConstantSDNode *SubC = dyn_cast<ConstantSDNode>(N2.getOperand(0))) {
2214 MVT::ValueType XType = N0.getValueType();
2215 if (SubC->isNullValue() && MVT::isInteger(XType)) {
2216 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0,
2217 DAG.getConstant(MVT::getSizeInBits(XType)-1,
2218 TLI.getShiftAmountTy()));
2219 SDOperand Add = DAG.getNode(ISD::ADD, XType, N0, Shift);
2220 WorkList.push_back(Shift.Val);
2221 WorkList.push_back(Add.Val);
2222 return DAG.getNode(ISD::XOR, XType, Add, Shift);
2230 SDOperand DAGCombiner::SimplifySetCC(MVT::ValueType VT, SDOperand N0,
2231 SDOperand N1, ISD::CondCode Cond,
2232 bool foldBooleans) {
2233 // These setcc operations always fold.
2237 case ISD::SETFALSE2: return DAG.getConstant(0, VT);
2239 case ISD::SETTRUE2: return DAG.getConstant(1, VT);
2242 if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val)) {
2243 uint64_t C1 = N1C->getValue();
2244 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val)) {
2245 uint64_t C0 = N0C->getValue();
2247 // Sign extend the operands if required
2248 if (ISD::isSignedIntSetCC(Cond)) {
2249 C0 = N0C->getSignExtended();
2250 C1 = N1C->getSignExtended();
2254 default: assert(0 && "Unknown integer setcc!");
2255 case ISD::SETEQ: return DAG.getConstant(C0 == C1, VT);
2256 case ISD::SETNE: return DAG.getConstant(C0 != C1, VT);
2257 case ISD::SETULT: return DAG.getConstant(C0 < C1, VT);
2258 case ISD::SETUGT: return DAG.getConstant(C0 > C1, VT);
2259 case ISD::SETULE: return DAG.getConstant(C0 <= C1, VT);
2260 case ISD::SETUGE: return DAG.getConstant(C0 >= C1, VT);
2261 case ISD::SETLT: return DAG.getConstant((int64_t)C0 < (int64_t)C1, VT);
2262 case ISD::SETGT: return DAG.getConstant((int64_t)C0 > (int64_t)C1, VT);
2263 case ISD::SETLE: return DAG.getConstant((int64_t)C0 <= (int64_t)C1, VT);
2264 case ISD::SETGE: return DAG.getConstant((int64_t)C0 >= (int64_t)C1, VT);
2267 // If the LHS is a ZERO_EXTEND, perform the comparison on the input.
2268 if (N0.getOpcode() == ISD::ZERO_EXTEND) {
2269 unsigned InSize = MVT::getSizeInBits(N0.getOperand(0).getValueType());
2271 // If the comparison constant has bits in the upper part, the
2272 // zero-extended value could never match.
2273 if (C1 & (~0ULL << InSize)) {
2274 unsigned VSize = MVT::getSizeInBits(N0.getValueType());
2278 case ISD::SETEQ: return DAG.getConstant(0, VT);
2281 case ISD::SETNE: return DAG.getConstant(1, VT);
2284 // True if the sign bit of C1 is set.
2285 return DAG.getConstant((C1 & (1ULL << VSize)) != 0, VT);
2288 // True if the sign bit of C1 isn't set.
2289 return DAG.getConstant((C1 & (1ULL << VSize)) == 0, VT);
2295 // Otherwise, we can perform the comparison with the low bits.
2303 return DAG.getSetCC(VT, N0.getOperand(0),
2304 DAG.getConstant(C1, N0.getOperand(0).getValueType()),
2307 break; // todo, be more careful with signed comparisons
2309 } else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
2310 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
2311 MVT::ValueType ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();
2312 unsigned ExtSrcTyBits = MVT::getSizeInBits(ExtSrcTy);
2313 MVT::ValueType ExtDstTy = N0.getValueType();
2314 unsigned ExtDstTyBits = MVT::getSizeInBits(ExtDstTy);
2316 // If the extended part has any inconsistent bits, it cannot ever
2317 // compare equal. In other words, they have to be all ones or all
2320 (~0ULL >> (64-ExtSrcTyBits)) & (~0ULL << (ExtDstTyBits-1));
2321 if ((C1 & ExtBits) != 0 && (C1 & ExtBits) != ExtBits)
2322 return DAG.getConstant(Cond == ISD::SETNE, VT);
2325 MVT::ValueType Op0Ty = N0.getOperand(0).getValueType();
2326 if (Op0Ty == ExtSrcTy) {
2327 ZextOp = N0.getOperand(0);
2329 int64_t Imm = ~0ULL >> (64-ExtSrcTyBits);
2330 ZextOp = DAG.getNode(ISD::AND, Op0Ty, N0.getOperand(0),
2331 DAG.getConstant(Imm, Op0Ty));
2333 WorkList.push_back(ZextOp.Val);
2334 // Otherwise, make this a use of a zext.
2335 return DAG.getSetCC(VT, ZextOp,
2336 DAG.getConstant(C1 & (~0ULL>>(64-ExtSrcTyBits)),
2341 uint64_t MinVal, MaxVal;
2342 unsigned OperandBitSize = MVT::getSizeInBits(N1C->getValueType(0));
2343 if (ISD::isSignedIntSetCC(Cond)) {
2344 MinVal = 1ULL << (OperandBitSize-1);
2345 if (OperandBitSize != 1) // Avoid X >> 64, which is undefined.
2346 MaxVal = ~0ULL >> (65-OperandBitSize);
2351 MaxVal = ~0ULL >> (64-OperandBitSize);
2354 // Canonicalize GE/LE comparisons to use GT/LT comparisons.
2355 if (Cond == ISD::SETGE || Cond == ISD::SETUGE) {
2356 if (C1 == MinVal) return DAG.getConstant(1, VT); // X >= MIN --> true
2357 --C1; // X >= C0 --> X > (C0-1)
2358 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()),
2359 (Cond == ISD::SETGE) ? ISD::SETGT : ISD::SETUGT);
2362 if (Cond == ISD::SETLE || Cond == ISD::SETULE) {
2363 if (C1 == MaxVal) return DAG.getConstant(1, VT); // X <= MAX --> true
2364 ++C1; // X <= C0 --> X < (C0+1)
2365 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()),
2366 (Cond == ISD::SETLE) ? ISD::SETLT : ISD::SETULT);
2369 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal)
2370 return DAG.getConstant(0, VT); // X < MIN --> false
2372 // Canonicalize setgt X, Min --> setne X, Min
2373 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MinVal)
2374 return DAG.getSetCC(VT, N0, N1, ISD::SETNE);
2375 // Canonicalize setlt X, Max --> setne X, Max
2376 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MaxVal)
2377 return DAG.getSetCC(VT, N0, N1, ISD::SETNE);
2379 // If we have setult X, 1, turn it into seteq X, 0
2380 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal+1)
2381 return DAG.getSetCC(VT, N0, DAG.getConstant(MinVal, N0.getValueType()),
2383 // If we have setugt X, Max-1, turn it into seteq X, Max
2384 else if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal-1)
2385 return DAG.getSetCC(VT, N0, DAG.getConstant(MaxVal, N0.getValueType()),
2388 // If we have "setcc X, C0", check to see if we can shrink the immediate
2391 // SETUGT X, SINTMAX -> SETLT X, 0
2392 if (Cond == ISD::SETUGT && OperandBitSize != 1 &&
2393 C1 == (~0ULL >> (65-OperandBitSize)))
2394 return DAG.getSetCC(VT, N0, DAG.getConstant(0, N1.getValueType()),
2397 // FIXME: Implement the rest of these.
2399 // Fold bit comparisons when we can.
2400 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
2401 VT == N0.getValueType() && N0.getOpcode() == ISD::AND)
2402 if (ConstantSDNode *AndRHS =
2403 dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
2404 if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0 --> (X & 8) >> 3
2405 // Perform the xform if the AND RHS is a single bit.
2406 if ((AndRHS->getValue() & (AndRHS->getValue()-1)) == 0) {
2407 return DAG.getNode(ISD::SRL, VT, N0,
2408 DAG.getConstant(Log2_64(AndRHS->getValue()),
2409 TLI.getShiftAmountTy()));
2411 } else if (Cond == ISD::SETEQ && C1 == AndRHS->getValue()) {
2412 // (X & 8) == 8 --> (X & 8) >> 3
2413 // Perform the xform if C1 is a single bit.
2414 if ((C1 & (C1-1)) == 0) {
2415 return DAG.getNode(ISD::SRL, VT, N0,
2416 DAG.getConstant(Log2_64(C1),TLI.getShiftAmountTy()));
2421 } else if (isa<ConstantSDNode>(N0.Val)) {
2422 // Ensure that the constant occurs on the RHS.
2423 return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond));
2426 if (ConstantFPSDNode *N0C = dyn_cast<ConstantFPSDNode>(N0.Val))
2427 if (ConstantFPSDNode *N1C = dyn_cast<ConstantFPSDNode>(N1.Val)) {
2428 double C0 = N0C->getValue(), C1 = N1C->getValue();
2431 default: break; // FIXME: Implement the rest of these!
2432 case ISD::SETEQ: return DAG.getConstant(C0 == C1, VT);
2433 case ISD::SETNE: return DAG.getConstant(C0 != C1, VT);
2434 case ISD::SETLT: return DAG.getConstant(C0 < C1, VT);
2435 case ISD::SETGT: return DAG.getConstant(C0 > C1, VT);
2436 case ISD::SETLE: return DAG.getConstant(C0 <= C1, VT);
2437 case ISD::SETGE: return DAG.getConstant(C0 >= C1, VT);
2440 // Ensure that the constant occurs on the RHS.
2441 return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond));
2445 // We can always fold X == Y for integer setcc's.
2446 if (MVT::isInteger(N0.getValueType()))
2447 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
2448 unsigned UOF = ISD::getUnorderedFlavor(Cond);
2449 if (UOF == 2) // FP operators that are undefined on NaNs.
2450 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
2451 if (UOF == unsigned(ISD::isTrueWhenEqual(Cond)))
2452 return DAG.getConstant(UOF, VT);
2453 // Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO
2454 // if it is not already.
2455 ISD::CondCode NewCond = UOF == 0 ? ISD::SETUO : ISD::SETO;
2456 if (NewCond != Cond)
2457 return DAG.getSetCC(VT, N0, N1, NewCond);
2460 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
2461 MVT::isInteger(N0.getValueType())) {
2462 if (N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::SUB ||
2463 N0.getOpcode() == ISD::XOR) {
2464 // Simplify (X+Y) == (X+Z) --> Y == Z
2465 if (N0.getOpcode() == N1.getOpcode()) {
2466 if (N0.getOperand(0) == N1.getOperand(0))
2467 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(1), Cond);
2468 if (N0.getOperand(1) == N1.getOperand(1))
2469 return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(0), Cond);
2470 if (isCommutativeBinOp(N0.getOpcode())) {
2471 // If X op Y == Y op X, try other combinations.
2472 if (N0.getOperand(0) == N1.getOperand(1))
2473 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(0), Cond);
2474 if (N0.getOperand(1) == N1.getOperand(0))
2475 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(1), Cond);
2479 // Turn (X^C1) == C2 into X == C1^C2 iff X&~C1 = 0. Common for condcodes.
2480 if (N0.getOpcode() == ISD::XOR)
2481 if (ConstantSDNode *XORC = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
2482 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(N1)) {
2483 // If we know that all of the inverted bits are zero, don't bother
2484 // performing the inversion.
2485 if (MaskedValueIsZero(N0.getOperand(0), ~XORC->getValue(), TLI))
2486 return DAG.getSetCC(VT, N0.getOperand(0),
2487 DAG.getConstant(XORC->getValue()^RHSC->getValue(),
2488 N0.getValueType()), Cond);
2491 // Simplify (X+Z) == X --> Z == 0
2492 if (N0.getOperand(0) == N1)
2493 return DAG.getSetCC(VT, N0.getOperand(1),
2494 DAG.getConstant(0, N0.getValueType()), Cond);
2495 if (N0.getOperand(1) == N1) {
2496 if (isCommutativeBinOp(N0.getOpcode()))
2497 return DAG.getSetCC(VT, N0.getOperand(0),
2498 DAG.getConstant(0, N0.getValueType()), Cond);
2500 assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!");
2501 // (Z-X) == X --> Z == X<<1
2502 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(),
2504 DAG.getConstant(1,TLI.getShiftAmountTy()));
2505 WorkList.push_back(SH.Val);
2506 return DAG.getSetCC(VT, N0.getOperand(0), SH, Cond);
2511 if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB ||
2512 N1.getOpcode() == ISD::XOR) {
2513 // Simplify X == (X+Z) --> Z == 0
2514 if (N1.getOperand(0) == N0) {
2515 return DAG.getSetCC(VT, N1.getOperand(1),
2516 DAG.getConstant(0, N1.getValueType()), Cond);
2517 } else if (N1.getOperand(1) == N0) {
2518 if (isCommutativeBinOp(N1.getOpcode())) {
2519 return DAG.getSetCC(VT, N1.getOperand(0),
2520 DAG.getConstant(0, N1.getValueType()), Cond);
2522 assert(N1.getOpcode() == ISD::SUB && "Unexpected operation!");
2523 // X == (Z-X) --> X<<1 == Z
2524 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(), N0,
2525 DAG.getConstant(1,TLI.getShiftAmountTy()));
2526 WorkList.push_back(SH.Val);
2527 return DAG.getSetCC(VT, SH, N1.getOperand(0), Cond);
2533 // Fold away ALL boolean setcc's.
2535 if (N0.getValueType() == MVT::i1 && foldBooleans) {
2537 default: assert(0 && "Unknown integer setcc!");
2538 case ISD::SETEQ: // X == Y -> (X^Y)^1
2539 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
2540 N0 = DAG.getNode(ISD::XOR, MVT::i1, Temp, DAG.getConstant(1, MVT::i1));
2541 WorkList.push_back(Temp.Val);
2543 case ISD::SETNE: // X != Y --> (X^Y)
2544 N0 = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
2546 case ISD::SETGT: // X >s Y --> X == 0 & Y == 1 --> X^1 & Y
2547 case ISD::SETULT: // X <u Y --> X == 0 & Y == 1 --> X^1 & Y
2548 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
2549 N0 = DAG.getNode(ISD::AND, MVT::i1, N1, Temp);
2550 WorkList.push_back(Temp.Val);
2552 case ISD::SETLT: // X <s Y --> X == 1 & Y == 0 --> Y^1 & X
2553 case ISD::SETUGT: // X >u Y --> X == 1 & Y == 0 --> Y^1 & X
2554 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
2555 N0 = DAG.getNode(ISD::AND, MVT::i1, N0, Temp);
2556 WorkList.push_back(Temp.Val);
2558 case ISD::SETULE: // X <=u Y --> X == 0 | Y == 1 --> X^1 | Y
2559 case ISD::SETGE: // X >=s Y --> X == 0 | Y == 1 --> X^1 | Y
2560 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
2561 N0 = DAG.getNode(ISD::OR, MVT::i1, N1, Temp);
2562 WorkList.push_back(Temp.Val);
2564 case ISD::SETUGE: // X >=u Y --> X == 1 | Y == 0 --> Y^1 | X
2565 case ISD::SETLE: // X <=s Y --> X == 1 | Y == 0 --> Y^1 | X
2566 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
2567 N0 = DAG.getNode(ISD::OR, MVT::i1, N0, Temp);
2570 if (VT != MVT::i1) {
2571 WorkList.push_back(N0.Val);
2572 // FIXME: If running after legalize, we probably can't do this.
2573 N0 = DAG.getNode(ISD::ZERO_EXTEND, VT, N0);
2578 // Could not fold it.
2582 /// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant,
2583 /// return a DAG expression to select that will generate the same value by
2584 /// multiplying by a magic number. See:
2585 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
2586 SDOperand DAGCombiner::BuildSDIV(SDNode *N) {
2587 MVT::ValueType VT = N->getValueType(0);
2589 // Check to see if we can do this.
2590 if (!TLI.isTypeLegal(VT) || (VT != MVT::i32 && VT != MVT::i64))
2591 return SDOperand(); // BuildSDIV only operates on i32 or i64
2592 if (!TLI.isOperationLegal(ISD::MULHS, VT))
2593 return SDOperand(); // Make sure the target supports MULHS.
2595 int64_t d = cast<ConstantSDNode>(N->getOperand(1))->getSignExtended();
2596 ms magics = (VT == MVT::i32) ? magic32(d) : magic64(d);
2598 // Multiply the numerator (operand 0) by the magic value
2599 SDOperand Q = DAG.getNode(ISD::MULHS, VT, N->getOperand(0),
2600 DAG.getConstant(magics.m, VT));
2601 // If d > 0 and m < 0, add the numerator
2602 if (d > 0 && magics.m < 0) {
2603 Q = DAG.getNode(ISD::ADD, VT, Q, N->getOperand(0));
2604 WorkList.push_back(Q.Val);
2606 // If d < 0 and m > 0, subtract the numerator.
2607 if (d < 0 && magics.m > 0) {
2608 Q = DAG.getNode(ISD::SUB, VT, Q, N->getOperand(0));
2609 WorkList.push_back(Q.Val);
2611 // Shift right algebraic if shift value is nonzero
2613 Q = DAG.getNode(ISD::SRA, VT, Q,
2614 DAG.getConstant(magics.s, TLI.getShiftAmountTy()));
2615 WorkList.push_back(Q.Val);
2617 // Extract the sign bit and add it to the quotient
2619 DAG.getNode(ISD::SRL, VT, Q, DAG.getConstant(MVT::getSizeInBits(VT)-1,
2620 TLI.getShiftAmountTy()));
2621 WorkList.push_back(T.Val);
2622 return DAG.getNode(ISD::ADD, VT, Q, T);
2625 /// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant,
2626 /// return a DAG expression to select that will generate the same value by
2627 /// multiplying by a magic number. See:
2628 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
2629 SDOperand DAGCombiner::BuildUDIV(SDNode *N) {
2630 MVT::ValueType VT = N->getValueType(0);
2632 // Check to see if we can do this.
2633 if (!TLI.isTypeLegal(VT) || (VT != MVT::i32 && VT != MVT::i64))
2634 return SDOperand(); // BuildUDIV only operates on i32 or i64
2635 if (!TLI.isOperationLegal(ISD::MULHU, VT))
2636 return SDOperand(); // Make sure the target supports MULHU.
2638 uint64_t d = cast<ConstantSDNode>(N->getOperand(1))->getValue();
2639 mu magics = (VT == MVT::i32) ? magicu32(d) : magicu64(d);
2641 // Multiply the numerator (operand 0) by the magic value
2642 SDOperand Q = DAG.getNode(ISD::MULHU, VT, N->getOperand(0),
2643 DAG.getConstant(magics.m, VT));
2644 WorkList.push_back(Q.Val);
2646 if (magics.a == 0) {
2647 return DAG.getNode(ISD::SRL, VT, Q,
2648 DAG.getConstant(magics.s, TLI.getShiftAmountTy()));
2650 SDOperand NPQ = DAG.getNode(ISD::SUB, VT, N->getOperand(0), Q);
2651 WorkList.push_back(NPQ.Val);
2652 NPQ = DAG.getNode(ISD::SRL, VT, NPQ,
2653 DAG.getConstant(1, TLI.getShiftAmountTy()));
2654 WorkList.push_back(NPQ.Val);
2655 NPQ = DAG.getNode(ISD::ADD, VT, NPQ, Q);
2656 WorkList.push_back(NPQ.Val);
2657 return DAG.getNode(ISD::SRL, VT, NPQ,
2658 DAG.getConstant(magics.s-1, TLI.getShiftAmountTy()));
2662 // SelectionDAG::Combine - This is the entry point for the file.
2664 void SelectionDAG::Combine(bool RunningAfterLegalize) {
2665 /// run - This is the main entry point to this class.
2667 DAGCombiner(*this).Run(RunningAfterLegalize);