[PATCH] D78493: [ARM] Don't shrink STM.W to unpredictable STM.N with writeback

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


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Comment at: llvm/lib/Target/ARM/Thumb2SizeReduction.cpp:525
 
+    // STM with writeback that stores the base register is unpredictable.
+    Register BaseReg = MI->getOperand(0).getReg();
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It's probably worth reorganizing the comments here to clarify: tSTMIA_UPD the only 16-bit STM.  So the Thumb2 instruction is fine, but the rewritten one would be unpredictable.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D78493/new/

https://reviews.llvm.org/D78493