[PATCH] D134612: [LoopUnroll] Forget block and loop dispositions during unrolling.

[Florian Hahn via Phabricator via llvm-commits]

fhahn updated this revision to Diff 463125.
fhahn added a comment.

Rebase on current `main`.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D134612/new/

https://reviews.llvm.org/D134612

Files:
  llvm/include/llvm/Analysis/ScalarEvolution.h
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/lib/Transforms/Utils/LoopUnroll.cpp


Index: llvm/lib/Transforms/Utils/LoopUnroll.cpp
===================================================================
--- llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -465,8 +465,10 @@
   if (SE) {
     if (ULO.ForgetAllSCEV)
       SE->forgetAllLoops();
-    else
+    else {
       SE->forgetTopmostLoop(L);
+      SE->forgetBlockAndLoopDispositions();
+    }
   }
 
   if (!LatchIsExiting)
Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -8384,6 +8384,11 @@
 
 void ScalarEvolution::forgetLoopDispositions() { LoopDispositions.clear(); }
 
+void ScalarEvolution::forgetBlockAndLoopDispositions() {
+  BlockDispositions.clear();
+  LoopDispositions.clear();
+}
+
 /// Get the exact loop backedge taken count considering all loop exits. A
 /// computable result can only be returned for loops with all exiting blocks
 /// dominating the latch. howFarToZero assumes that the limit of each loop test
Index: llvm/include/llvm/Analysis/ScalarEvolution.h
===================================================================
--- llvm/include/llvm/Analysis/ScalarEvolution.h
+++ llvm/include/llvm/Analysis/ScalarEvolution.h
@@ -939,6 +939,13 @@
   /// recompute is simpler.
   void forgetLoopDispositions();
 
+  /// Called when the client has changed the disposition of values in
+  /// a loop or block.
+  ///
+  /// We don't have a way to invalidate per-loop/per-block dispositions. Clear
+  /// and recompute is simpler.
+  void forgetBlockAndLoopDispositions();
+
   /// Determine the minimum number of zero bits that S is guaranteed to end in
   /// (at every loop iteration).  It is, at the same time, the minimum number
   /// of times S is divisible by 2.  For example, given {4,+,8} it returns 2.


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D134612.463125.patch
Type: text/x-patch
Size: 1894 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220927/f6760564/attachment.bin>