[PATCH] D84100: [ARM] Optimize immediate selection

[Sam Parker via Phabricator via llvm-commits]

samparker added inline comments.


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Comment at: llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp:3319
+        NewUseOpc1 = UseOpc == ARM::ADDrr ? ARM::ADDri : ARM::SUBri;
+        NewUseOpc2 = UseOpc == ARM::ADDrr ? ARM::ADDri : ARM::SUBri;
+      } else if (ARM_AM::isSOImmTwoPartVal(-ImmVal)) {
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NewUseOpc2 = NewUseOpc1, same for below.


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Comment at: llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp:3365
+      if (ARM_AM::isT2SOImmTwoPartVal(ImmVal)) {
+        NewUseOpc1 = UseOpc == ARM::t2ADDrr ? t2ADD : t2SUB;
+        NewUseOpc2 = UseOpc == ARM::t2ADDrr ? t2ADD : t2SUB;
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NewUseOpc2 = NewUseOpc1, same for below.


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Comment at: llvm/test/CodeGen/ARM/add-sub-imm.ll:2
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -mtriple=arm-eabi %s -o - | FileCheck %s --check-prefix=CHECK
 
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We should have a test run for a Thumb2 target as well. It would also be a good idea for some edge-case negative tests to exercise isSOImmTwoPartValSub some more.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D84100/new/

https://reviews.llvm.org/D84100