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InstCombine: Add a missing irem identity (X % X -> 0).

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119538 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer
2010-11-17 19:11:46 +00:00
parent 2b749870d0
commit 1951a5b721
2 changed files with 9 additions and 0 deletions
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4
lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
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@ -551,6 +551,10 @@ Instruction *InstCombiner::commonIRemTransforms(BinaryOperator &I) {
if (Instruction *common = commonRemTransforms(I)) if (Instruction *common = commonRemTransforms(I))
return common; return common;
// X % X == 0
if (Op0 == Op1)
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
// 0 % X == 0 for integer, we don't need to preserve faults! // 0 % X == 0 for integer, we don't need to preserve faults!
if (Constant *LHS = dyn_cast<Constant>(Op0)) if (Constant *LHS = dyn_cast<Constant>(Op0))
if (LHS->isNullValue()) if (LHS->isNullValue())

5
test/Transforms/InstCombine/rem.ll
View File

@ -81,3 +81,8 @@ define i32 @test12(i32 %i) {
%tmp.5 = srem i32 %tmp.1, 2 %tmp.5 = srem i32 %tmp.1, 2
ret i32 %tmp.5 ret i32 %tmp.5
} }
define i32 @test13(i32 %i) {
%x = srem i32 %i, %i
ret i32 %x
}