From 4658ce9c1f023ca8198add9eabc9ec466d23c8cb Mon Sep 17 00:00:00 2001 From: Jim Grosbach Date: Fri, 16 Aug 2013 00:15:20 +0000 Subject: InstCombine: Simplify if(x!=0 && x!=-1). When both constants are positive or both constants are negative, InstCombine already simplifies comparisons like this, but when it's exactly zero and -1, the operand sorting ends up reversed and the pattern fails to match. Handle that special case. Follow up for rdar://14689217 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188512 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/InstCombine/InstCombineAndOrXor.cpp | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp index b474bd8..bc8506a 100644 --- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -849,10 +849,15 @@ Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) { case ICmpInst::ICMP_SGT: // (X != 13 & X s> 15) -> X s> 15 return RHS; case ICmpInst::ICMP_NE: + // Special case to get the ordering right when the values wrap around + // zero. + if (LHSCst->getValue() == 0 && RHSCst->getValue() == -1) + std::swap(LHSCst, RHSCst); if (LHSCst == SubOne(RHSCst)){// (X != 13 & X != 14) -> X-13 >u 1 Constant *AddCST = ConstantExpr::getNeg(LHSCst); Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off"); - return Builder->CreateICmpUGT(Add, ConstantInt::get(Add->getType(), 1)); + return Builder->CreateICmpUGT(Add, ConstantInt::get(Add->getType(), 1), + Val->getName()+".cmp"); } break; // (X != 13 & X != 15) -> no change } -- cgit v1.1