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| author | Chris Lattner <sabre@nondot.org> | 2011-02-17 02:23:02 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2011-02-17 02:23:02 +0000 |
| commit | 5592071768cfeef8f113db2ca6708723f31ed871 (patch) | |
| tree | 6653f3a3c79154d81baad705d1496dac794f6cc9 | |
| parent | 0ad64291d8e916a0e1fb520a0dc86e087e7423a5 (diff) | |
| download | bcm5719-llvm-5592071768cfeef8f113db2ca6708723f31ed871.tar.gz bcm5719-llvm-5592071768cfeef8f113db2ca6708723f31ed871.zip | |
preserve NUW/NSW when transforming add x,x
llvm-svn: 125711
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | 9 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/add2.ll | 8 |
2 files changed, 15 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp index 4ff005e26c2..89cc540da71 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -147,8 +147,13 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) { return BinaryOperator::CreateXor(LHS, RHS); // X + X --> X << 1 - if (LHS == RHS && I.getType()->isIntegerTy()) - return BinaryOperator::CreateShl(LHS, ConstantInt::get(I.getType(), 1)); + if (LHS == RHS && I.getType()->isIntegerTy()) { + BinaryOperator *New = + BinaryOperator::CreateShl(LHS, ConstantInt::get(I.getType(), 1)); + New->setHasNoSignedWrap(I.hasNoSignedWrap()); + New->setHasNoUnsignedWrap(I.hasNoUnsignedWrap()); + return New; + } // -A + B --> B - A // -A + -B --> -(A + B) diff --git a/llvm/test/Transforms/InstCombine/add2.ll b/llvm/test/Transforms/InstCombine/add2.ll index a382142d73a..c5109c52885 100644 --- a/llvm/test/Transforms/InstCombine/add2.ll +++ b/llvm/test/Transforms/InstCombine/add2.ll @@ -33,3 +33,11 @@ define i32 @test3(i32 %A) { ; CHECK-NEXT: ret i32 } +define i32 @test4(i32 %A) { + %B = add nuw i32 %A, %A + ret i32 %B +; CHECK: @test4 +; CHECK-NEXT: %B = shl nuw i32 %A, 1 +; CHECK-NEXT: ret i32 %B +} + |
