[PATCH] D143895: [AArch64] Fix incorrect `isLegalAddressingMode`

[Dave Green via Phabricator via llvm-commits]

dmgreen added a comment.

I can certainly imagine that we haven't got Addressing modes without a BaseReg entirely correct in the past and just assumed it was present. The change in IsSimplerBaseSCEVForTarget I added recently and look more correct now.



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Comment at: llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp:3186
   if (!isAlwaysFoldable(TTI, LSRUse::Address, AccessTy, /*BaseGV=*/nullptr,
-                        IncOffset, /*HasBaseReg=*/false))
+                        IncOffset, /*HasBaseReg=*/true))
     return false;
----------------
Can you give more details why this is changed to HasBaseReg? It seems that isAlwaysFoldable already sets ScaledReg to 1 or -1, so this now tests for BaseReg + 1/-1*ScaledReg + IncOffset?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D143895/new/

https://reviews.llvm.org/D143895