[PATCH] D26802: [X86][AVX512] Detect repeated constant patterns in BUILD_VECTOR suitable for broadcasting.

[Simon Pilgrim via llvm-commits]

RKSimon added reviewers: RKSimon, spatel.
RKSimon added a comment.

Thanks for looking at this - there is a lot of potential here for constant pool savings - sign/zero extension also come to mind.

I'm worried about always enabling this - your tests break a lot of memory folds which could cause register pressure issues, so we'd trade a small constant pool saving for increased instruction counts/complexity and stack usage.

I tried to detail this here https://llvm.org/bugs/show_bug.cgi?id=27141#c5



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Comment at: test/CodeGen/X86/avx-logic.ll:3
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=+avx | FileCheck %s -check-prefix=AVX
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=+avx512f | FileCheck %s -check-prefix=AVX512F
 
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If you add --check-prefix=CHECK as the first FileCheck then many of these test should collapse.


https://reviews.llvm.org/D26802