From 8a23270ce60fdd5dafa1c8dfbf9f46c8efe244b7 Mon Sep 17 00:00:00 2001 From: Nick Lewycky Date: Fri, 12 Jul 2013 23:42:57 +0000 Subject: 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 --- lib/Analysis/InstructionSimplify.cpp | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'lib/Analysis/InstructionSimplify.cpp') diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index d66ecca928..52c0456586 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 -- cgit v1.2.3