constant fold bits_convert in getNode and in the dag combiner for fp<->int

conversions.  This allows V8 to compiles this:

void %test() {
        call float %test2( float 1.000000e+00, float 2.000000e+00, double 3.000000e+00, double* null )
        ret void
}

into:

test:
        save -96, %o6, %o6
        sethi 0, %o3
        sethi 1049088, %o2
        sethi 1048576, %o1
        sethi 1040384, %o0
        or %g0, %o3, %o4
        call test2
        nop
        restore %g0, %g0, %g0
        retl
        nop

instead of:

test:
        save -112, %o6, %o6
        sethi 0, %o4
        sethi 1049088, %l0
        st %o4, [%i6+-12]
        st %l0, [%i6+-16]
        ld [%i6+-12], %o3
        ld [%i6+-16], %o2
        sethi 1048576, %o1
        sethi 1040384, %o0
        call test2
        nop
        restore %g0, %g0, %g0
        retl
        nop

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24980 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 87c6cf0f90aabf2751ad88694425b2f3fd5e1ee2..ad26719dca89dfb2dd402e220f30ed991fbe92b2 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -151,6 +151,7 @@ namespace {
     SDOperand visitZERO_EXTEND(SDNode *N);
     SDOperand visitSIGN_EXTEND_INREG(SDNode *N);
     SDOperand visitTRUNCATE(SDNode *N);
+    SDOperand visitBIT_CONVERT(SDNode *N);
     
     SDOperand visitFADD(SDNode *N);
     SDOperand visitFSUB(SDNode *N);
@@ -609,6 +610,7 @@ SDOperand DAGCombiner::visit(SDNode *N) {
   case ISD::ZERO_EXTEND:        return visitZERO_EXTEND(N);
   case ISD::SIGN_EXTEND_INREG:  return visitSIGN_EXTEND_INREG(N);
   case ISD::TRUNCATE:           return visitTRUNCATE(N);
+  case ISD::BIT_CONVERT:        return visitBIT_CONVERT(N);
   case ISD::FADD:               return visitFADD(N);
   case ISD::FSUB:               return visitFSUB(N);
   case ISD::FMUL:               return visitFMUL(N);
@@ -1745,6 +1747,19 @@ SDOperand DAGCombiner::visitTRUNCATE(SDNode *N) {
   return SDOperand();
 }
 
+SDOperand DAGCombiner::visitBIT_CONVERT(SDNode *N) {
+  SDOperand N0 = N->getOperand(0);
+  MVT::ValueType VT = N->getValueType(0);
+
+  // If the input is a constant, let getNode() fold it.
+  if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) {
+    SDOperand Res = DAG.getNode(ISD::BIT_CONVERT, VT, N0);
+    if (Res.Val != N) return Res;
+  }
+  
+  return SDOperand();
+}
+
 SDOperand DAGCombiner::visitFADD(SDNode *N) {
   SDOperand N0 = N->getOperand(0);
   SDOperand N1 = N->getOperand(1);

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index ec75dfee32ae4a437f6f35a10427f3cab54b8cd3..76d983f57e878cb0f1226fe381456df113b3a33a 100644 (file)
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -828,6 +828,7 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT) {
 
 SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
                                 SDOperand Operand) {
+  // Constant fold unary operations with an integer constant operand.
   if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Operand.Val)) {
     uint64_t Val = C->getValue();
     switch (Opcode) {
@@ -838,13 +839,25 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
     case ISD::TRUNCATE:    return getConstant(Val, VT);
     case ISD::SINT_TO_FP:  return getConstantFP(C->getSignExtended(), VT);
     case ISD::UINT_TO_FP:  return getConstantFP(C->getValue(), VT);
+    case ISD::BIT_CONVERT:
+      if (VT == MVT::f32) {
+        assert(C->getValueType(0) == MVT::i32 && "Invalid bit_convert!");
+        return getConstantFP(BitsToFloat(Val), VT);
+      } else if (VT == MVT::f64) {
+        assert(C->getValueType(0) == MVT::i64 && "Invalid bit_convert!");
+        return getConstantFP(BitsToDouble(Val), VT);
+      }
+      break;
     }
   }
 
+  // Constant fold unary operations with an floating point constant operand.
   if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(Operand.Val))
     switch (Opcode) {
     case ISD::FNEG:
       return getConstantFP(-C->getValue(), VT);
+    case ISD::FABS:
+      return getConstantFP(fabs(C->getValue()), VT);
     case ISD::FP_ROUND:
     case ISD::FP_EXTEND:
       return getConstantFP(C->getValue(), VT);
@@ -852,6 +865,15 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
       return getConstant((int64_t)C->getValue(), VT);
     case ISD::FP_TO_UINT:
       return getConstant((uint64_t)C->getValue(), VT);
+    case ISD::BIT_CONVERT:
+      if (VT == MVT::i32) {
+        assert(C->getValueType(0) == MVT::f32 && "Invalid bit_convert!");
+        return getConstant(FloatToBits(C->getValue()), VT);
+      } else if (VT == MVT::i64) {
+        assert(C->getValueType(0) == MVT::f64 && "Invalid bit_convert!");
+        return getConstant(DoubleToBits(C->getValue()), VT);
+      }
+      break;
     }
 
   unsigned OpOpcode = Operand.Val->getOpcode();