[PATCH] D31169: [DAGCombiner] Initial support for the fast-math flag contract

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


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Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:8721-8725
+  if (!isContractable(N))
+    return SDValue();
 
   // Floating-point multiply-add with intermediate rounding.
   bool HasFMAD = (LegalOperations && TLI.isOperationLegal(ISD::FMAD, VT));
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spatel wrote:
> If the target has FMAD, then did we just bail out unnecessarily?
Yes, the point of fmad is it is safe anyway


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Comment at: test/CodeGen/AArch64/neon-fma-FMF.ll:13
+; CHECK-LABEL: no_fma_1:
+; CHECK-NOT: fmla
+	%tmp1 = fmul contract <2 x float> %A, %B;
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Positive checks for the separate add and mul would be less fragile


https://reviews.llvm.org/D31169