[PatternMatch] allow undef elements when matching vector FP +0.0
This continues the FP constant pattern matching improvements from:
https://reviews.llvm.org/rL327627
https://reviews.llvm.org/rL327339
https://reviews.llvm.org/rL327307
Several integer constant matchers also have this ability. I'm
separating matching of integer/pointer null from FP positive zero
and renaming/commenting to make the functionality clearer.
llvm-svn: 328461
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index bdd1a58..f5400f9 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2362,7 +2362,7 @@
// Folding cmp(sub(a,b),0) -> cmp(a,b) and cmp(0,sub(a,b)) -> cmp(b,a)
Value *Arg0 = II->getArgOperand(0);
Value *Arg1 = II->getArgOperand(1);
- bool Arg0IsZero = match(Arg0, m_Zero());
+ bool Arg0IsZero = match(Arg0, m_PosZeroFP());
if (Arg0IsZero)
std::swap(Arg0, Arg1);
Value *A, *B;
@@ -2374,7 +2374,7 @@
// The compare intrinsic uses the above assumptions and therefore
// doesn't require additional flags.
if ((match(Arg0, m_OneUse(m_FSub(m_Value(A), m_Value(B)))) &&
- match(Arg1, m_Zero()) && isa<Instruction>(Arg0) &&
+ match(Arg1, m_PosZeroFP()) && isa<Instruction>(Arg0) &&
cast<Instruction>(Arg0)->getFastMathFlags().noInfs())) {
if (Arg0IsZero)
std::swap(A, B);