[PATCH] D86939: [LSR] Canonicalize a formula before insert it into the list

[Mindong Chen via Phabricator via llvm-commits]

mdchen created this revision.
mdchen added reviewers: qcolombet, mkazantsev, amehsan.
mdchen added a project: LLVM.
Herald added subscribers: llvm-commits, hiraditya.
mdchen requested review of this revision.

In GenerateConstantOffsetsImpl, we may generate non canonical
Formula if BaseRegs of that Formula is updated and includes a
recurrent expr reg related with current loop while its ScaledReg
is not.

Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=47329


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D86939

Files:
  llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp


Index: llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -3836,8 +3836,12 @@
     return;
   if (IsScaledReg)
     F.ScaledReg = G;
-  else
+  else {
     F.BaseRegs[Idx] = G;
+    // We may generate non canonical Formula if G is a recurrent expr reg
+    // related with current loop while F.ScaledReg is not.
+    F.canonicalize(*L);
+  }
   (void)InsertFormula(LU, LUIdx, F);
 }
 


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