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| author | Chris Lattner <sabre@nondot.org> | 2011-02-06 22:05:31 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2011-02-06 22:05:31 +0000 |
| commit | c6ee9181a51fdfa3c07e1e53695681c55aa98ce4 (patch) | |
| tree | 1b11913f91b212aa9a03e4a16ee307d609a9a7c2 | |
| parent | c35a44d3d73a429e59fb3044ee723db0511862f2 (diff) | |
| download | llvm-c6ee9181a51fdfa3c07e1e53695681c55aa98ce4.tar.gz llvm-c6ee9181a51fdfa3c07e1e53695681c55aa98ce4.tar.bz2 llvm-c6ee9181a51fdfa3c07e1e53695681c55aa98ce4.tar.xz | |
teach instsimplify to transform (X / Y) * Y to X
when the div is an exact udiv.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124994 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Analysis/InstructionSimplify.cpp | 8 | ||||
| -rw-r--r-- | test/Transforms/InstSimplify/reassociate.ll | 20 |
2 files changed, 25 insertions, 3 deletions
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index 220868fe1d..7bb8f69992 100644 --- a/lib/Analysis/InstructionSimplify.cpp +++ b/lib/Analysis/InstructionSimplify.cpp @@ -735,9 +735,11 @@ static Value *SimplifyMulInst(Value *Op0, Value *Op1, const TargetData *TD, // (X / Y) * Y -> X if the division is exact. Value *X = 0, *Y = 0; if ((match(Op0, m_SDiv(m_Value(X), m_Value(Y))) && Y == Op1) || // (X / Y) * Y - (match(Op1, m_SDiv(m_Value(X), m_Value(Y))) && Y == Op0)) { // Y * (X / Y) - BinaryOperator *SDiv = cast<BinaryOperator>(Y == Op1 ? Op0 : Op1); - if (SDiv->isExact()) + (match(Op0, m_UDiv(m_Value(X), m_Value(Y))) && Y == Op1) || + (match(Op1, m_SDiv(m_Value(X), m_Value(Y))) && Y == Op0) || // Y * (X / Y) + (match(Op1, m_UDiv(m_Value(X), m_Value(Y))) && Y == Op0)) { + BinaryOperator *Div = cast<BinaryOperator>(Y == Op1 ? Op0 : Op1); + if (Div->isExact()) return X; } diff --git a/test/Transforms/InstSimplify/reassociate.ll b/test/Transforms/InstSimplify/reassociate.ll index 928442ac56..3c8169e5e2 100644 --- a/test/Transforms/InstSimplify/reassociate.ll +++ b/test/Transforms/InstSimplify/reassociate.ll @@ -137,6 +137,7 @@ define i32 @sdiv5(i32 %x, i32 %y) { ; CHECK: ret i32 %x } + define i32 @udiv1(i32 %x, i32 %y) { ; CHECK: @udiv1 ; (no overflow X * Y) / Y -> X @@ -164,3 +165,22 @@ define i32 @udiv3(i32 %x, i32 %y) { ret i32 %div ; CHECK: ret i32 0 } + +define i32 @udiv4(i32 %x, i32 %y) { +; CHECK: @udiv4 +; (X / Y) * Y -> X if the division is exact + %div = udiv exact i32 %x, %y + %mul = mul i32 %div, %y + ret i32 %mul +; CHECK: ret i32 %x +} + +define i32 @udiv5(i32 %x, i32 %y) { +; CHECK: @udiv5 +; Y * (X / Y) -> X if the division is exact + %div = udiv exact i32 %x, %y + %mul = mul i32 %y, %div + ret i32 %mul +; CHECK: ret i32 %x +} + |