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| author | Chris Lattner <sabre@nondot.org> | 2008-04-19 22:17:26 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2008-04-19 22:17:26 +0000 |
| commit | 510fabb24c0a6db38a87d33b65ff90e5b1377015 (patch) | |
| tree | 759c384cfde897c617a82b0d6ef9c061e37818db | |
| parent | 69e4c5b6ff7532bfaf94bd102377be02af891761 (diff) | |
| download | external_llvm-510fabb24c0a6db38a87d33b65ff90e5b1377015.zip external_llvm-510fabb24c0a6db38a87d33b65ff90e5b1377015.tar.gz external_llvm-510fabb24c0a6db38a87d33b65ff90e5b1377015.tar.bz2 | |
Implement PR2206.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49967 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/VMCore/ConstantFold.cpp | 25 | ||||
| -rw-r--r-- | test/Assembler/ConstantExprFold.llx | 4 |
2 files changed, 21 insertions, 8 deletions
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp index c15ce96..353a149 100644 --- a/lib/VMCore/ConstantFold.cpp +++ b/lib/VMCore/ConstantFold.cpp @@ -548,8 +548,8 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, if (CI2->isAllOnesValue()) return const_cast<Constant*>(C1); // X & -1 == X - // (zext i32 to i64) & 4294967295 -> (zext i32 to i64) if (const ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) { + // (zext i32 to i64) & 4294967295 -> (zext i32 to i64) if (CE1->getOpcode() == Instruction::ZExt) { unsigned DstWidth = CI2->getType()->getBitWidth(); unsigned SrcWidth = @@ -559,16 +559,25 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, return const_cast<Constant*>(C1); } + // If and'ing the address of a global with a constant, fold it. if (CE1->getOpcode() == Instruction::PtrToInt && isa<GlobalValue>(CE1->getOperand(0))) { - GlobalValue *CPR = cast<GlobalValue>(CE1->getOperand(0)); + GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0)); - // Functions are at least 4-byte aligned. If and'ing the address of a - // function with a constant < 4, fold it to zero. - if (const ConstantInt *CI = dyn_cast<ConstantInt>(C2)) - if (CI->getValue().ult(APInt(CI->getType()->getBitWidth(),4)) && - isa<Function>(CPR)) - return Constant::getNullValue(CI->getType()); + // Functions are at least 4-byte aligned. + unsigned GVAlign = GV->getAlignment(); + if (isa<Function>(GV)) + GVAlign = std::max(GVAlign, 4U); + + if (GVAlign > 1) { + unsigned DstWidth = CI2->getType()->getBitWidth(); + unsigned SrcWidth = std::min(SrcWidth, Log2_32(GVAlign)); + APInt BitsNotSet(APInt::getLowBitsSet(DstWidth, SrcWidth)); + + // If checking bits we know are clear, return zero. + if ((CI2->getValue() & BitsNotSet) == CI2->getValue()) + return Constant::getNullValue(CI2->getType()); + } } } break; diff --git a/test/Assembler/ConstantExprFold.llx b/test/Assembler/ConstantExprFold.llx index e32cc66..89edc24 100644 --- a/test/Assembler/ConstantExprFold.llx +++ b/test/Assembler/ConstantExprFold.llx @@ -24,3 +24,7 @@ global i1 icmp slt (i32* getelementptr (%Ty* @B, i64 0, i32 0), i32* getelementptr (%Ty* @B, i64 0, i32 1)) ; true ;global i1 icmp ne (i64* @A, i64* bitcast (%Ty* @B to i64*)) ; true +; PR2206 +@cons = weak global i32 0, align 8 ; <i32*> [#uses=1] +global i64 and (i64 ptrtoint (i32* @cons to i64), i64 7) + |