#include "llvm/Pass.h"
#include "llvm/DerivedTypes.h"
#include "llvm/GlobalVariable.h"
+#include "llvm/ParameterAttributes.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
private:
Instruction *visitCallSite(CallSite CS);
bool transformConstExprCastCall(CallSite CS);
+ Instruction *transformCallThroughTrampoline(CallSite CS);
public:
// InsertNewInstBefore - insert an instruction New before instruction Old
if (RHSC->isNullValue())
return ReplaceInstUsesWith(I, LHS);
} else if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
- if (CFP->isExactlyValue(-0.0))
+ if (CFP->isExactlyValue(ConstantFP::getNegativeZero
+ (I.getType())->getValueAPF()))
return ReplaceInstUsesWith(I, LHS);
}
Constant *CP1 = Subtract(ConstantInt::get(I.getType(), 1), C2);
return BinaryOperator::createMul(Op0, CP1);
}
+
+ // X - ((X / Y) * Y) --> X % Y
+ if (Op1I->getOpcode() == Instruction::Mul)
+ if (Instruction *I = dyn_cast<Instruction>(Op1I->getOperand(0)))
+ if (Op0 == I->getOperand(0) &&
+ Op1I->getOperand(1) == I->getOperand(1)) {
+ if (I->getOpcode() == Instruction::SDiv)
+ return BinaryOperator::createSRem(Op0, Op1I->getOperand(1));
+ if (I->getOpcode() == Instruction::UDiv)
+ return BinaryOperator::createURem(Op0, Op1I->getOperand(1));
+ }
}
}
// "In IEEE floating point, x*1 is not equivalent to x for nans. However,
// ANSI says we can drop signals, so we can do this anyway." (from GCC)
- if (Op1F->isExactlyValue(1.0))
- return ReplaceInstUsesWith(I, Op0); // Eliminate 'mul double %X, 1.0'
+ // We need a better interface for long double here.
+ if (Op1->getType() == Type::FloatTy || Op1->getType() == Type::DoubleTy)
+ if (Op1F->isExactlyValue(1.0))
+ return ReplaceInstUsesWith(I, Op0); // Eliminate 'mul double %X, 1.0'
}
if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0))
/// getICmpValue - This is the complement of getICmpCode, which turns an
/// opcode and two operands into either a constant true or false, or a brand
-/// new /// ICmp instruction. The sign is passed in to determine which kind
+/// new ICmp instruction. The sign is passed in to determine which kind
/// of predicate to use in new icmp instructions.
static Value *getICmpValue(bool sign, unsigned code, Value *LHS, Value *RHS) {
switch (code) {
if (isa<UndefValue>(Op1)) // X icmp undef -> undef
return ReplaceInstUsesWith(I, UndefValue::get(Type::Int1Ty));
- // icmp of GlobalValues can never equal each other as long as they aren't
- // external weak linkage type.
- if (GlobalValue *GV0 = dyn_cast<GlobalValue>(Op0))
- if (GlobalValue *GV1 = dyn_cast<GlobalValue>(Op1))
- if (!GV0->hasExternalWeakLinkage() || !GV1->hasExternalWeakLinkage())
- return ReplaceInstUsesWith(I, ConstantInt::get(Type::Int1Ty,
- !isTrueWhenEqual(I)));
-
// icmp <global/alloca*/null>, <global/alloca*/null> - Global/Stack value
// addresses never equal each other! We already know that Op0 != Op1.
if ((isa<GlobalValue>(Op0) || isa<AllocaInst>(Op0) ||
assert(Val->getType() == Type::Int32Ty && "Unexpected allocation size type!");
if (ConstantInt *CI = dyn_cast<ConstantInt>(Val)) {
Offset = CI->getZExtValue();
- Scale = 1;
+ Scale = 0;
return ConstantInt::get(Type::Int32Ty, 0);
- } else if (Instruction *I = dyn_cast<Instruction>(Val)) {
- if (I->getNumOperands() == 2) {
- if (ConstantInt *CUI = dyn_cast<ConstantInt>(I->getOperand(1))) {
- if (I->getOpcode() == Instruction::Shl) {
- // This is a value scaled by '1 << the shift amt'.
- Scale = 1U << CUI->getZExtValue();
- Offset = 0;
- return I->getOperand(0);
- } else if (I->getOpcode() == Instruction::Mul) {
- // This value is scaled by 'CUI'.
- Scale = CUI->getZExtValue();
- Offset = 0;
- return I->getOperand(0);
- } else if (I->getOpcode() == Instruction::Add) {
- // We have X+C. Check to see if we really have (X*C2)+C1,
- // where C1 is divisible by C2.
- unsigned SubScale;
- Value *SubVal =
- DecomposeSimpleLinearExpr(I->getOperand(0), SubScale, Offset);
- Offset += CUI->getZExtValue();
- if (SubScale > 1 && (Offset % SubScale == 0)) {
- Scale = SubScale;
- return SubVal;
- }
- }
+ } else if (BinaryOperator *I = dyn_cast<BinaryOperator>(Val)) {
+ if (ConstantInt *RHS = dyn_cast<ConstantInt>(I->getOperand(1))) {
+ if (I->getOpcode() == Instruction::Shl) {
+ // This is a value scaled by '1 << the shift amt'.
+ Scale = 1U << RHS->getZExtValue();
+ Offset = 0;
+ return I->getOperand(0);
+ } else if (I->getOpcode() == Instruction::Mul) {
+ // This value is scaled by 'RHS'.
+ Scale = RHS->getZExtValue();
+ Offset = 0;
+ return I->getOperand(0);
+ } else if (I->getOpcode() == Instruction::Add) {
+ // We have X+C. Check to see if we really have (X*C2)+C1,
+ // where C1 is divisible by C2.
+ unsigned SubScale;
+ Value *SubVal =
+ DecomposeSimpleLinearExpr(I->getOperand(0), SubScale, Offset);
+ Offset += RHS->getZExtValue();
+ Scale = SubScale;
+ return SubVal;
}
}
}
// of casts in the input.
if (I->getOpcode() == CastOpc)
return true;
+
break;
default:
// TODO: Can handle more cases here.
if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) {
if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) {
// Transform (X == Y) ? X : Y -> Y
- if (FCI->getPredicate() == FCmpInst::FCMP_OEQ)
+ if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
+ // This is not safe in general for floating point:
+ // consider X== -0, Y== +0.
+ // It becomes safe if either operand is a nonzero constant.
+ ConstantFP *CFPt, *CFPf;
+ if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
+ !CFPt->getValueAPF().isZero()) ||
+ ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
+ !CFPf->getValueAPF().isZero()))
return ReplaceInstUsesWith(SI, FalseVal);
+ }
// Transform (X != Y) ? X : Y -> X
if (FCI->getPredicate() == FCmpInst::FCMP_ONE)
return ReplaceInstUsesWith(SI, TrueVal);
} else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){
// Transform (X == Y) ? Y : X -> X
- if (FCI->getPredicate() == FCmpInst::FCMP_OEQ)
- return ReplaceInstUsesWith(SI, FalseVal);
+ if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
+ // This is not safe in general for floating point:
+ // consider X== -0, Y== +0.
+ // It becomes safe if either operand is a nonzero constant.
+ ConstantFP *CFPt, *CFPf;
+ if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
+ !CFPt->getValueAPF().isZero()) ||
+ ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
+ !CFPf->getValueAPF().isZero()))
+ return ReplaceInstUsesWith(SI, FalseVal);
+ }
// Transform (X != Y) ? Y : X -> Y
if (FCI->getPredicate() == FCmpInst::FCMP_ONE)
return ReplaceInstUsesWith(SI, TrueVal);
MI->setAlignment(ConstantInt::get(Type::Int32Ty, Align));
Changed = true;
}
+
+ // If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with
+ // load/store.
+ ConstantInt *MemOpLength = dyn_cast<ConstantInt>(CI.getOperand(3));
+ if (MemOpLength) {
+ unsigned Size = MemOpLength->getZExtValue();
+ unsigned Align = cast<ConstantInt>(CI.getOperand(4))->getZExtValue();
+ PointerType *NewPtrTy = NULL;
+ // Destination pointer type is always i8 *
+ // If Size is 8 then use Int64Ty
+ // If Size is 4 then use Int32Ty
+ // If Size is 2 then use Int16Ty
+ // If Size is 1 then use Int8Ty
+ if (Size && Size <=8 && !(Size&(Size-1)))
+ NewPtrTy = PointerType::get(IntegerType::get(Size<<3));
+
+ if (NewPtrTy) {
+ Value *Src = InsertCastBefore(Instruction::BitCast, CI.getOperand(2), NewPtrTy, CI);
+ Value *Dest = InsertCastBefore(Instruction::BitCast, CI.getOperand(1), NewPtrTy, CI);
+ Value *L = new LoadInst(Src, "tmp", false, Align, &CI);
+ Value *NS = new StoreInst(L, Dest, false, Align, &CI);
+ AddToWorkList(cast<Instruction>(L));
+ AddToWorkList(cast<Instruction>(NS));
+ CI.replaceAllUsesWith(NS);
+ Changed = true;
+ return EraseInstFromFunction(CI);
+ }
+ }
} else if (isa<MemSetInst>(MI)) {
unsigned Alignment = GetOrEnforceKnownAlignment(MI->getDest(), TD);
if (MI->getAlignment()->getZExtValue() < Alignment) {
return EraseInstFromFunction(*CS.getInstruction());
}
+ if (BitCastInst *BC = dyn_cast<BitCastInst>(Callee))
+ if (IntrinsicInst *In = dyn_cast<IntrinsicInst>(BC->getOperand(0)))
+ if (In->getIntrinsicID() == Intrinsic::init_trampoline)
+ return transformCallThroughTrampoline(CS);
+
const PointerType *PTy = cast<PointerType>(Callee->getType());
const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
if (FTy->isVarArg()) {
return true;
}
+// transformCallThroughTrampoline - Turn a call to a function created by the
+// init_trampoline intrinsic into a direct call to the underlying function.
+//
+Instruction *InstCombiner::transformCallThroughTrampoline(CallSite CS) {
+ Value *Callee = CS.getCalledValue();
+ const PointerType *PTy = cast<PointerType>(Callee->getType());
+ const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
+
+ IntrinsicInst *Tramp =
+ cast<IntrinsicInst>(cast<BitCastInst>(Callee)->getOperand(0));
+
+ Function *NestF =
+ cast<Function>(IntrinsicInst::StripPointerCasts(Tramp->getOperand(2)));
+ const PointerType *NestFPTy = cast<PointerType>(NestF->getType());
+ const FunctionType *NestFTy = cast<FunctionType>(NestFPTy->getElementType());
+
+ if (const ParamAttrsList *NestAttrs = NestFTy->getParamAttrs()) {
+ unsigned NestIdx = 1;
+ const Type *NestTy = 0;
+ uint16_t NestAttr = 0;
+
+ // Look for a parameter marked with the 'nest' attribute.
+ for (FunctionType::param_iterator I = NestFTy->param_begin(),
+ E = NestFTy->param_end(); I != E; ++NestIdx, ++I)
+ if (NestAttrs->paramHasAttr(NestIdx, ParamAttr::Nest)) {
+ // Record the parameter type and any other attributes.
+ NestTy = *I;
+ NestAttr = NestAttrs->getParamAttrs(NestIdx);
+ break;
+ }
+
+ if (NestTy) {
+ Instruction *Caller = CS.getInstruction();
+ std::vector<Value*> NewArgs;
+ NewArgs.reserve(unsigned(CS.arg_end()-CS.arg_begin())+1);
+
+ // Insert the nest argument into the call argument list, which may
+ // mean appending it.
+ {
+ unsigned Idx = 1;
+ CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
+ do {
+ if (Idx == NestIdx) {
+ // Add the chain argument.
+ Value *NestVal = Tramp->getOperand(3);
+ if (NestVal->getType() != NestTy)
+ NestVal = new BitCastInst(NestVal, NestTy, "nest", Caller);
+ NewArgs.push_back(NestVal);
+ }
+
+ if (I == E)
+ break;
+
+ // Add the original argument.
+ NewArgs.push_back(*I);
+
+ ++Idx, ++I;
+ } while (1);
+ }
+
+ // The trampoline may have been bitcast to a bogus type (FTy).
+ // Handle this by synthesizing a new function type, equal to FTy
+ // with the chain parameter inserted. Likewise for attributes.
+
+ const ParamAttrsList *Attrs = FTy->getParamAttrs();
+ std::vector<const Type*> NewTypes;
+ ParamAttrsVector NewAttrs;
+ NewTypes.reserve(FTy->getNumParams()+1);
+
+ // Add any function result attributes.
+ uint16_t Attr = Attrs ? Attrs->getParamAttrs(0) : 0;
+ if (Attr)
+ NewAttrs.push_back (ParamAttrsWithIndex::get(0, Attr));
+
+ // Insert the chain's type into the list of parameter types, which may
+ // mean appending it. Likewise for the chain's attributes.
+ {
+ unsigned Idx = 1;
+ FunctionType::param_iterator I = FTy->param_begin(),
+ E = FTy->param_end();
+
+ do {
+ if (Idx == NestIdx) {
+ // Add the chain's type and attributes.
+ NewTypes.push_back(NestTy);
+ NewAttrs.push_back(ParamAttrsWithIndex::get(NestIdx, NestAttr));
+ }
+
+ if (I == E)
+ break;
+
+ // Add the original type and attributes.
+ NewTypes.push_back(*I);
+ Attr = Attrs ? Attrs->getParamAttrs(Idx) : 0;
+ if (Attr)
+ NewAttrs.push_back
+ (ParamAttrsWithIndex::get(Idx + (Idx >= NestIdx), Attr));
+
+ ++Idx, ++I;
+ } while (1);
+ }
+
+ // Replace the trampoline call with a direct call. Let the generic
+ // code sort out any function type mismatches.
+ FunctionType *NewFTy =
+ FunctionType::get(FTy->getReturnType(), NewTypes, FTy->isVarArg(),
+ ParamAttrsList::get(NewAttrs));
+ Constant *NewCallee = NestF->getType() == PointerType::get(NewFTy) ?
+ NestF : ConstantExpr::getBitCast(NestF, PointerType::get(NewFTy));
+
+ Instruction *NewCaller;
+ if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
+ NewCaller = new InvokeInst(NewCallee,
+ II->getNormalDest(), II->getUnwindDest(),
+ NewArgs.begin(), NewArgs.end(),
+ Caller->getName(), Caller);
+ cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv());
+ } else {
+ NewCaller = new CallInst(NewCallee, NewArgs.begin(), NewArgs.end(),
+ Caller->getName(), Caller);
+ if (cast<CallInst>(Caller)->isTailCall())
+ cast<CallInst>(NewCaller)->setTailCall();
+ cast<CallInst>(NewCaller)->
+ setCallingConv(cast<CallInst>(Caller)->getCallingConv());
+ }
+ if (Caller->getType() != Type::VoidTy && !Caller->use_empty())
+ Caller->replaceAllUsesWith(NewCaller);
+ Caller->eraseFromParent();
+ RemoveFromWorkList(Caller);
+ return 0;
+ }
+ }
+
+ // Replace the trampoline call with a direct call. Since there is no 'nest'
+ // parameter, there is no need to adjust the argument list. Let the generic
+ // code sort out any function type mismatches.
+ Constant *NewCallee =
+ NestF->getType() == PTy ? NestF : ConstantExpr::getBitCast(NestF, PTy);
+ CS.setCalledFunction(NewCallee);
+ return CS.getInstruction();
+}
+
/// FoldPHIArgBinOpIntoPHI - If we have something like phi [add (a,b), add(c,d)]
/// and if a/b/c/d and the add's all have a single use, turn this into two phi's
/// and a single binop.
// If this GEP instruction doesn't move the pointer, and if the input operand
// is a bitcast of another pointer, just replace the GEP with a bitcast of the
// real input to the dest type.
- if (GEP.hasAllZeroIndices() && isa<BitCastInst>(GEP.getOperand(0)))
- return new BitCastInst(cast<BitCastInst>(GEP.getOperand(0))->getOperand(0),
- GEP.getType());
-
+ if (GEP.hasAllZeroIndices()) {
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(GEP.getOperand(0))) {
+ // If the bitcast is of an allocation, and the allocation will be
+ // converted to match the type of the cast, don't touch this.
+ if (isa<AllocationInst>(BCI->getOperand(0))) {
+ // See if the bitcast simplifies, if so, don't nuke this GEP yet.
+ if (Instruction *I = visitBitCast(*BCI)) {
+ if (I != BCI) {
+ I->takeName(BCI);
+ BCI->getParent()->getInstList().insert(BCI, I);
+ ReplaceInstUsesWith(*BCI, I);
+ }
+ return &GEP;
+ }
+ }
+ return new BitCastInst(BCI->getOperand(0), GEP.getType());
+ }
+ }
+
// Combine Indices - If the source pointer to this getelementptr instruction
// is a getelementptr instruction, combine the indices of the two
// getelementptr instructions into a single instruction.
/// specified pointer, we do a quick local scan of the basic block containing
/// ScanFrom, to determine if the address is already accessed.
static bool isSafeToLoadUnconditionally(Value *V, Instruction *ScanFrom) {
- // If it is an alloca or global variable, it is always safe to load from.
- if (isa<AllocaInst>(V) || isa<GlobalVariable>(V)) return true;
+ // If it is an alloca it is always safe to load from.
+ if (isa<AllocaInst>(V)) return true;
+
+ // If it is a global variable it is mostly safe to load from.
+ if (const GlobalValue *GV = dyn_cast<GlobalVariable>(V))
+ // Don't try to evaluate aliases. External weak GV can be null.
+ return !isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage();
// Otherwise, be a little bit agressive by scanning the local block where we
// want to check to see if the pointer is already being loaded or stored
}
} else if (CE->isCast()) {
+ // Instead of loading constant c string, use corresponding integer value
+ // directly if string length is small enough.
+ const std::string &Str = CE->getOperand(0)->getStringValue();
+ if (!Str.empty()) {
+ unsigned len = Str.length();
+ const Type *Ty = cast<PointerType>(CE->getType())->getElementType();
+ unsigned numBits = Ty->getPrimitiveSizeInBits();
+ if ((numBits >> 3) == len + 1) {
+ // Replace LI with immediate integer store.
+ APInt StrVal(numBits, 0);
+ APInt SingleChar(numBits, 0);
+ for (unsigned i = 0; i < len; i++) {
+ SingleChar = (uint64_t) Str[i];
+ StrVal = (StrVal << 8) | SingleChar;
+ }
+ // Append NULL at the end.
+ SingleChar = 0;
+ StrVal = (StrVal << 8) | SingleChar;
+ Value *NL = ConstantInt::get(StrVal);
+ return ReplaceInstUsesWith(LI, NL);
+ }
+ }
+
if (Instruction *Res = InstCombineLoadCast(*this, LI))
return Res;
}
// the pointer we're loading and is producing the pointer we're storing,
// then *this* store is dead (X = load P; store X -> P).
if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) {
- if (LI == Val && LI->getOperand(0) == Ptr) {
+ if (LI == Val && LI->getOperand(0) == Ptr && !SI.isVolatile()) {
EraseInstFromFunction(SI);
++NumCombined;
return 0;
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