diff options
Diffstat (limited to 'lib/CodeGen/CGExprScalar.cpp')
| -rw-r--r-- | lib/CodeGen/CGExprScalar.cpp | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp index d76cad2c56..3ec4040a64 100644 --- a/lib/CodeGen/CGExprScalar.cpp +++ b/lib/CodeGen/CGExprScalar.cpp @@ -2407,13 +2407,17 @@ Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) { if (CGF.SanOpts->Shift && !CGF.getLangOpts().OpenCL && isa<llvm::IntegerType>(Ops.LHS->getType())) { llvm::Value *WidthMinusOne = GetWidthMinusOneValue(Ops.LHS, RHS); - // FIXME: Emit the branching explicitly rather than emitting the check - // twice. - EmitBinOpCheck(Builder.CreateICmpULE(RHS, WidthMinusOne), Ops); + llvm::Value *Valid = Builder.CreateICmpULE(RHS, WidthMinusOne); if (Ops.Ty->hasSignedIntegerRepresentation()) { + llvm::BasicBlock *Orig = Builder.GetInsertBlock(); + llvm::BasicBlock *Cont = CGF.createBasicBlock("cont"); + llvm::BasicBlock *CheckBitsShifted = CGF.createBasicBlock("check"); + Builder.CreateCondBr(Valid, CheckBitsShifted, Cont); + // Check whether we are shifting any non-zero bits off the top of the // integer. + CGF.EmitBlock(CheckBitsShifted); llvm::Value *BitsShiftedOff = Builder.CreateLShr(Ops.LHS, Builder.CreateSub(WidthMinusOne, RHS, "shl.zeros", @@ -2428,8 +2432,15 @@ Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) { BitsShiftedOff = Builder.CreateLShr(BitsShiftedOff, One); } llvm::Value *Zero = llvm::ConstantInt::get(BitsShiftedOff->getType(), 0); - EmitBinOpCheck(Builder.CreateICmpEQ(BitsShiftedOff, Zero), Ops); + llvm::Value *SecondCheck = Builder.CreateICmpEQ(BitsShiftedOff, Zero); + CGF.EmitBlock(Cont); + llvm::PHINode *P = Builder.CreatePHI(Valid->getType(), 2); + P->addIncoming(Valid, Orig); + P->addIncoming(SecondCheck, CheckBitsShifted); + Valid = P; } + + EmitBinOpCheck(Valid, Ops); } // OpenCL 6.3j: shift values are effectively % word size of LHS. if (CGF.getLangOpts().OpenCL) |