[PATCH] D100079: [Attributor] Don't modify functions outside of the current SCC

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks created this revision.
Herald added a reviewer: uenoku.
Herald added subscribers: okura, kuter, uenoku.
Herald added a reviewer: homerdin.
aeubanks requested review of this revision.
Herald added a reviewer: jdoerfert.
Herald added a reviewer: sstefan1.
Herald added a reviewer: baziotis.
Herald added subscribers: llvm-commits, bbn.
Herald added a project: LLVM.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D100079

Files:
  llvm/include/llvm/Transforms/IPO/Attributor.h


Index: llvm/include/llvm/Transforms/IPO/Attributor.h
===================================================================
--- llvm/include/llvm/Transforms/IPO/Attributor.h
+++ llvm/include/llvm/Transforms/IPO/Attributor.h
@@ -1331,6 +1331,8 @@
   /// Record that \p U is to be replaces with \p NV after information was
   /// manifested. This also triggers deletion of trivially dead istructions.
   bool changeUseAfterManifest(Use &U, Value &NV) {
+    if (!canChangeUse(U))
+      return false;
     Value *&V = ToBeChangedUses[&U];
     if (V && (V->stripPointerCasts() == NV.stripPointerCasts() ||
               isa_and_nonnull<UndefValue>(V)))
@@ -1341,6 +1343,14 @@
     return true;
   }
 
+  bool canChangeUse(Use &U) {
+    if (Functions.empty())
+      return true;
+    if (auto *I = dyn_cast<Instruction>(U.getUser()))
+      return Functions.contains(I->getParent()->getParent());
+    return false;
+  }
+
   /// Helper function to replace all uses of \p V with \p NV. Return true if
   /// there is any change. The flag \p ChangeDroppable indicates if dropppable
   /// uses should be changed too.
@@ -1348,7 +1358,7 @@
                                 bool ChangeDroppable = true) {
     bool Changed = false;
     for (auto &U : V.uses())
-      if (ChangeDroppable || !U.getUser()->isDroppable())
+      if ((ChangeDroppable || !U.getUser()->isDroppable()) && canChangeUse(U))
         Changed |= changeUseAfterManifest(U, NV);
 
     return Changed;


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