[PATCH] D144534: [InstCombine] Fold (fcmp_oeq (fabs x) +Inf) into is_fpclass(x, fcInf)

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

I think this is a backwards canonicalization decision and fabs + fcmp will be more broadly understood



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Comment at: llvm/test/Transforms/InstCombine/create-class-from-logic-fcmp.ll:1160
 ; CHECK-LABEL: @not_negisnormalinf_or_inf(
-; CHECK-NEXT:    [[FABS:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
-; CHECK-NEXT:    [[NOT_IS_NEG_NORMAL_INF:%.*]] = fcmp ult half [[X]], 0xH0400
-; CHECK-NEXT:    [[IS_INF:%.*]] = fcmp oeq half [[FABS]], 0xH7C00
-; CHECK-NEXT:    [[OR:%.*]] = or i1 [[NOT_IS_NEG_NORMAL_INF]], [[IS_INF]]
-; CHECK-NEXT:    ret i1 [[OR]]
+; CHECK-NEXT:    [[IS_INF:%.*]] = call i1 @llvm.is.fpclass.f16(half [[X:%.*]], i32 767)
+; CHECK-NEXT:    ret i1 [[IS_INF]]
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This improvement will be picked up whenever my patch to combine class+fcmp lands


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D144534/new/

https://reviews.llvm.org/D144534