[PATCH] D49585: [ARM] Prefer lsls+lsrs over lsls+ands or lsrs+ands in Thumb1.

Fri Jul 20 00:39:09 PDT 2018

SjoerdMeijer added a comment.

Nice optimisation, looks good to me.

About where this should go, I am also not so sure. Looks like this is not so different from what's already done in Select, but I would propably first have thought about a Combine, and am not sure if it matters.

Perhaps @samparker has an opinion on this.

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Comment at: test/CodeGen/Thumb/shift-and.ll:1
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=thumb-eabi %s -o - | FileCheck %s
----------------
Nit: remove the NOTE.

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Comment at: test/CodeGen/Thumb/shift-and.ll:6
+; CHECK-LABEL: test1:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    lsls r0, r0, #20
----------------
Nit: do we need to match bb.0 and entry? Perhaps that's convenient for the check-next.

Repository:
  rL LLVM

https://reviews.llvm.org/D49585