[PATCH] D139311: InstCombine: Match pattern that appears in clang's __builtin_isnormal

[Serge Pavlov via Phabricator via llvm-commits]

sepavloff added inline comments.


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Comment at: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp:1217-1220
+/// Matches canonical form of isnan, fcmp ord x, 0
+static bool matchIsNaN(FCmpInst::Predicate P, Value *LHS, Value *RHS) {
+  return P == FCmpInst::FCMP_ORD && match(RHS, m_AnyZeroFP());
+}
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As this is `fcmp ord`, the name `matchIsNotNaN` would be better.

IR producer (not necessarily clang) may chose any form of NaN check, so the check must test both forms, `fcmp ord x, const` or `fcmp ord x, x`.


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Comment at: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp:1232
+/// Clang emits this pattern for doing an isfinite check in __builtin_isnormal.
+static Value *matchOrdAndUnorderedCmpInf(InstCombiner::BuilderTy &Builder,
+                                         FCmpInst *LHS, FCmpInst *RHS) {
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The function name is not clear enough. Why not `matchFiniteTest()` or something similar?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D139311/new/

https://reviews.llvm.org/D139311