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| author | Nick Lewycky <nicholas@mxc.ca> | 2013-07-12 23:42:57 +0000 |
|---|---|---|
| committer | Nick Lewycky <nicholas@mxc.ca> | 2013-07-12 23:42:57 +0000 |
| commit | 8a23270ce60fdd5dafa1c8dfbf9f46c8efe244b7 (patch) | |
| tree | f0c7d5e97d2647ecb530397bf29b4add5350cc37 | |
| parent | 434c0bd2a5c3c7ebaa8ca10dd7e4fdb1f25e92a0 (diff) | |
| download | external_llvm-8a23270ce60fdd5dafa1c8dfbf9f46c8efe244b7.zip external_llvm-8a23270ce60fdd5dafa1c8dfbf9f46c8efe244b7.tar.gz external_llvm-8a23270ce60fdd5dafa1c8dfbf9f46c8efe244b7.tar.bz2 | |
Fix logic error optimizing "icmp pred (urem X, Y), Y" where pred is signed.
Fixes PR16605.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186229 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Analysis/InstructionSimplify.cpp | 11 | ||||
| -rw-r--r-- | test/Transforms/InstSimplify/compare.ll | 10 |
2 files changed, 16 insertions, 5 deletions
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index d66ecca..52c0456 100644 --- a/lib/Analysis/InstructionSimplify.cpp +++ b/lib/Analysis/InstructionSimplify.cpp @@ -2246,6 +2246,7 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, } } + // icmp pred (urem X, Y), Y if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) { bool KnownNonNegative, KnownNegative; switch (Pred) { @@ -2253,7 +2254,7 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, break; case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_SGE: - ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD); + ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD); if (!KnownNonNegative) break; // fall-through @@ -2263,7 +2264,7 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, return getFalse(ITy); case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_SLE: - ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD); + ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD); if (!KnownNonNegative) break; // fall-through @@ -2273,6 +2274,8 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, return getTrue(ITy); } } + + // icmp pred X, (urem Y, X) if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) { bool KnownNonNegative, KnownNegative; switch (Pred) { @@ -2280,7 +2283,7 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, break; case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_SGE: - ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD); + ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD); if (!KnownNonNegative) break; // fall-through @@ -2290,7 +2293,7 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, return getTrue(ITy); case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_SLE: - ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD); + ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD); if (!KnownNonNegative) break; // fall-through diff --git a/test/Transforms/InstSimplify/compare.ll b/test/Transforms/InstSimplify/compare.ll index 82d5602..a0a9c85 100644 --- a/test/Transforms/InstSimplify/compare.ll +++ b/test/Transforms/InstSimplify/compare.ll @@ -480,7 +480,7 @@ define i1 @urem5(i16 %X, i32 %Y) { %B = urem i32 %A, %Y %C = icmp slt i32 %B, %Y ret i1 %C -; CHECK: ret i1 true +; CHECK-NOT: ret i1 true } define i1 @urem6(i32 %X, i32 %Y) { @@ -491,6 +491,14 @@ define i1 @urem6(i32 %X, i32 %Y) { ; CHECK: ret i1 true } +define i1 @urem7(i32 %X) { +; CHECK: @urem7 + %A = urem i32 1, %X + %B = icmp sgt i32 %A, %X + ret i1 %B +; CHECK-NOT: ret i1 false +} + define i1 @srem1(i32 %X) { ; CHECK: @srem1 %A = srem i32 %X, -5 |