[PATCH] D149260: [AArch64] Emit FNMADD instead of FNEG(FMADD)

[David Sherwood via Phabricator via llvm-commits]

david-arm added inline comments.


================
Comment at: llvm/lib/Target/AArch64/AArch64InstrInfo.cpp:5437
+  case AArch64::FNEGDr:
+    Found |= Match(AArch64::FMADDDrrr, MachineCombinerPattern::FNMADDD);
+    break;
----------------
Shouldn't we also be doing FMSUB here too, to ensure we are also requiring the nsz flag for the existing fnmsub combine?


================
Comment at: llvm/test/CodeGen/AArch64/aarch64_fnmadd.ll:86
+
+define dso_local void @neg_fnmadds_contract(ptr %a, ptr %b, ptr %c) {
+; CHECK-LABEL: neg_fnmadds_contract:
----------------
nit: This is just a minor thing, but at first I though `@neg` referred to negation here, given the combine involves a `fneg`. Perhaps it's less confusing to just remove it and add a comment above the negative test cases explaining why the combine doesn't happen?


Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D149260/new/

https://reviews.llvm.org/D149260