[PATCH] D127119: [SLP]Fix undef handling in gather function.

[Vasileios Porpodas via Phabricator via llvm-commits]

vporpo added inline comments.


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Comment at: llvm/test/Transforms/SLPVectorizer/X86/buildvector-same-lane-insert.ll:48
+; CHECK-NEXT:    [[TMP8:%.*]] = shufflevector <2 x float> undef, <2 x float> [[TMP3]], <2 x i32> <i32 2, i32 1>
+; CHECK-NEXT:    [[TMP9:%.*]] = shufflevector <2 x float> [[TMP8]], <2 x float> [[TMP3]], <2 x i32> <i32 0, i32 3>
 ; CHECK-NEXT:    store <2 x float> [[TMP9]], ptr null, align 4
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TMP9 seems to be redundant here, it looks like it is a copy of TMP3:
TMP8 is: TMP3[0], undef
TMP9 is: TMP3[0], TMP3[1]

I guess this was an issue even before this patch: TMP8 was a copy of TMP3, so the TMP8 shufflevector was redundant.



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D127119/new/

https://reviews.llvm.org/D127119