diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineCompares.cpp | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp index 274758ccb4..cebe37b7b0 100644 --- a/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -1795,6 +1795,20 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { if (Value *V = SimplifyICmpInst(I.getPredicate(), Op0, Op1, TD)) return ReplaceInstUsesWith(I, V); + // comparing -val or val with non-zero is the same as just comparing val + // ie, (val != 0) == (-val != 0) + if (I.getPredicate() == ICmpInst::ICMP_NE && match(Op1, m_Zero())) + { + Value *Cond, *SubSrc, *SelectFalse; + if (match(Op0, m_Select(m_Value(Cond), m_Sub(m_Zero(), m_Value(SubSrc)), + m_Value(SelectFalse)))) { + if (SubSrc == SelectFalse) { + return CmpInst::Create(Instruction::ICmp, I.getPredicate(), + SubSrc, Op1); + } + } + } + Type *Ty = Op0->getType(); // icmp's with boolean values can always be turned into bitwise operations |