[PATCH] D99283: [GlobalISel] Combine and (lshr x, cst), mask -> ubfx x, cst, width

[Jessica Paquette via Phabricator via llvm-commits]

paquette added inline comments.


================
Comment at: llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerCombiner.cpp:282-285
+  // Only legal for s32 and s64.
+  LLT Ty = MRI.getType(Dst);
+  if (Ty != LLT::scalar(32) && Ty != LLT::scalar(64))
+    return false;
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arsenm wrote:
> This is the only target specific thing here which can be replaced with a legality check on UBFX
The annoying part (for AArch64) is that the legality checks don't work with custom legalization.

I'm not sure what the best way to handle custom actions is.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99283/new/

https://reviews.llvm.org/D99283