diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 13 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/2008-07-08-SubAnd.ll | 9 |
2 files changed, 21 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index f8ad98c517..675f7ec571 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -3461,6 +3461,17 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) { // ((A ^ N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0 if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, true, I)) return BinaryOperator::CreateAnd(V, AndRHS); + + // (A - N) & AndRHS -> -N & AndRHS where A & AndRHS == 0 + if (Op0I->hasOneUse() && MaskedValueIsZero(Op0LHS, AndRHSMask)) { + ConstantInt *A = dyn_cast<ConstantInt>(Op0LHS); + if (!A || !A->isZero()) { + Instruction *NewNeg = BinaryOperator::CreateNeg(Op0RHS); + InsertNewInstBefore(NewNeg, I); + return BinaryOperator::CreateAnd(NewNeg, AndRHS); + } + } + break; } @@ -3780,7 +3791,7 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) { } } } - + return Changed ? &I : 0; } diff --git a/test/Transforms/InstCombine/2008-07-08-SubAnd.ll b/test/Transforms/InstCombine/2008-07-08-SubAnd.ll new file mode 100644 index 0000000000..bf3afb9e3b --- /dev/null +++ b/test/Transforms/InstCombine/2008-07-08-SubAnd.ll @@ -0,0 +1,9 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep -v {i32 8} +; PR2330 + +define i32 @a(i32 %a) nounwind { +entry: + %tmp2 = sub i32 8, %a ; <i32> [#uses=1] + %tmp3 = and i32 %tmp2, 7 ; <i32> [#uses=1] + ret i32 %tmp3 +} |