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| author | Bill Wendling <isanbard@gmail.com> | 2008-12-01 07:47:02 +0000 |
|---|---|---|
| committer | Bill Wendling <isanbard@gmail.com> | 2008-12-01 07:47:02 +0000 |
| commit | f2e0efd309bdb08bec9aca8a18b62914eca995ec (patch) | |
| tree | a738708e582ae3271e528ec68728ada3abe080ca /lib/Transforms | |
| parent | 66a3a3e0dbe3f2341999a7d8a1b0b3527f38a411 (diff) | |
| download | external_llvm-f2e0efd309bdb08bec9aca8a18b62914eca995ec.zip external_llvm-f2e0efd309bdb08bec9aca8a18b62914eca995ec.tar.gz external_llvm-f2e0efd309bdb08bec9aca8a18b62914eca995ec.tar.bz2 | |
Move pattern check outside of the if-then statement. This prevents us from fiddling with constants unless we have to.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60340 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms')
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index bc87444..aae1e14 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -2928,17 +2928,19 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) { if (RHS->isAllOnesValue()) return BinaryOperator::CreateNeg(Op0); - ConstantInt *RHSNeg = cast<ConstantInt>(ConstantExpr::getNeg(RHS)); - APInt RHSNegAPI(RHSNeg->getValue()); - - APInt NegOne = -APInt(RHSNeg->getBitWidth(), 1, true); - APInt TwoToExp(RHSNeg->getBitWidth(), 1 << (RHSNeg->getBitWidth() - 1)); - // -X/C -> X/-C, if and only if negation doesn't overflow. - if ((RHS->getValue().isNegative() && RHSNegAPI.slt(TwoToExp - 1)) || - (RHS->getValue().isNonNegative() && RHSNegAPI.sgt(TwoToExp * NegOne))) { - if (Value *LHSNeg = dyn_castNegVal(Op0)) { - if (ConstantInt *CI = dyn_cast<ConstantInt>(LHSNeg)) { + if (Value *LHSNeg = dyn_castNegVal(Op0)) { + if (ConstantInt *CI = dyn_cast<ConstantInt>(LHSNeg)) { + ConstantInt *RHSNeg = cast<ConstantInt>(ConstantExpr::getNeg(RHS)); + APInt RHSNegAPI(RHSNeg->getValue()); + + APInt NegOne = -APInt(RHSNeg->getBitWidth(), 1, true); + APInt TwoToExp(RHSNeg->getBitWidth(), 1 << (RHSNeg->getBitWidth() - 1)); + + if ((RHS->getValue().isNegative() && + RHSNegAPI.slt(TwoToExp - 1)) || + (RHS->getValue().isNonNegative() && + RHSNegAPI.sgt(TwoToExp * NegOne))) { ConstantInt *CINeg = cast<ConstantInt>(ConstantExpr::getNeg(CI)); APInt CINegAPI(CINeg->getValue()); |