[PATCH] D65954: [Reassociate] try harder to convert negative FP constants to positive

[Sanjay Patel via Phabricator via llvm-commits]

spatel marked an inline comment as done.
spatel added inline comments.


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Comment at: llvm/test/Transforms/Reassociate/reassoc-intermediate-fnegs.ll:9-12
+; CHECK-NEXT:    [[T2_NEG:%.*]] = fmul fast half [[A:%.*]], 0xHC500
 ; CHECK-NEXT:    [[REASS_MUL:%.*]] = fmul fast half [[B:%.*]], 0xH4500
-; CHECK-NEXT:    [[T51:%.*]] = fsub fast half [[REASS_MUL]], [[T2_NEG]]
 ; CHECK-NEXT:    [[T5:%.*]] = fadd fast half [[REASS_MUL]], [[T2_NEG]]
+; CHECK-NEXT:    ret half [[T5]]
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I stepped through this case, and we don't remove the negative constant because ShouldBreakUpSubtract() is true. Even with the positive constant, we failed to factorize, so this needs work either way.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D65954/new/

https://reviews.llvm.org/D65954