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| author | Chris Lattner <sabre@nondot.org> | 2006-01-06 07:22:22 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2006-01-06 07:22:22 +0000 |
| commit | b330939d90736d09b9a9a1c0e1fc16012ec343b1 (patch) | |
| tree | 78cb19bb04ad6c401ffb5ba1de4cb8864fdb29c8 /llvm/lib | |
| parent | 145539343f8c43d57081fc81651ab7bb4d2186ec (diff) | |
| download | bcm5719-llvm-b330939d90736d09b9a9a1c0e1fc16012ec343b1.tar.gz bcm5719-llvm-b330939d90736d09b9a9a1c0e1fc16012ec343b1.zip | |
Simplify the code a bit more
llvm-svn: 25126
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index 48aab3d4647..3ba239b6a69 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -3449,13 +3449,15 @@ Instruction *InstCombiner::visitShiftInst(ShiftInst &I) { Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantUInt *Op1, ShiftInst &I) { bool isLeftShift = I.getOpcode() == Instruction::Shl; + bool isSignedShift = Op0->getType()->isSigned(); + bool isUnsignedShift = !isSignedShift; // shl uint X, 32 = 0 and shr ubyte Y, 9 = 0, ... just don't eliminate shr // of a signed value. // unsigned TypeBits = Op0->getType()->getPrimitiveSizeInBits(); if (Op1->getValue() >= TypeBits) { - if (!Op0->getType()->isSigned() || isLeftShift) + if (isUnsignedShift || isLeftShift) return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType())); else { I.setOperand(1, ConstantUInt::get(Type::UByteTy, TypeBits-1)); @@ -3625,7 +3627,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantUInt *Op1, // the constant which would cause it to be modified for this // operation. // - if (isValid && !isLeftShift && !I.getType()->isUnsigned()) { + if (isValid && !isLeftShift && isSignedShift) { uint64_t Val = Op0C->getRawValue(); isValid = ((Val & (1 << (TypeBits-1))) != 0) == highBitSet; } @@ -3665,7 +3667,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantUInt *Op1, // Check for (A << c1) >> c2 or visaversa. If we are dealing with // signed types, we can only support the (A >> c1) << c2 configuration, // because it can not turn an arbitrary bit of A into a sign bit. - if (I.getType()->isUnsigned() || isLeftShift) { + if (isUnsignedShift || isLeftShift) { // Calculate bitmask for what gets shifted off the edge... Constant *C = ConstantIntegral::getAllOnesValue(I.getType()); if (isLeftShift) |
