[PATCH] D101924: [X86] Improve costmodel for scalar byte swaps

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added a comment.

Random comment: This has me wishing that we'd made further progress with D46276 <https://reviews.llvm.org/D46276> - I'd much prefer being able to peer into the scheduler models for costs than relying on yet more feature flags :(



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Comment at: llvm/lib/Target/X86/X86.td:519
+    : SubtargetFeature<"fast-movbe", "HasFastMOVBE", "true",
+    "Prefer a movbe over a single-use load + bswap / single-use bswap + store">;
+
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You say 'prefer' - is a future intention to alter isel depending on this? I'm not sure that's actually useful.


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Comment at: llvm/test/Transforms/SLPVectorizer/X86/bitreverse.ll:30
+; SSE-NEXT:    ret void
+;
+; XOP-LABEL: @bitreverse_2i64(
----------------
AVX?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D101924/new/

https://reviews.llvm.org/D101924