[llvm] 807d432 - [VPlan] Use properlyDominates predicate for ordering FOR users.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2023-02-13T21:24:58Z
New Revision: 807d43239a5fe0bb93d64925393bb99abbd81a92

URL: https://github.com/llvm/llvm-project/commit/807d43239a5fe0bb93d64925393bb99abbd81a92
DIFF: https://github.com/llvm/llvm-project/commit/807d43239a5fe0bb93d64925393bb99abbd81a92.diff

LOG: [VPlan] Use properlyDominates predicate for ordering FOR users.

The current implementation may return true for A < B and B < A, which
may cause issues if the sort implementation assures this property of the
comperator. This should fix a crash with MSVC.

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index 10a67081a0d09..568f9ab095e5c 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -549,8 +549,8 @@ static VPRegionBlock *GetReplicateRegion(VPRecipeBase *R) {
   return nullptr;
 }
 
-static bool dominates(const VPRecipeBase *A, const VPRecipeBase *B,
-                      VPDominatorTree &VPDT) {
+static bool properlyDominates(const VPRecipeBase *A, const VPRecipeBase *B,
+                              VPDominatorTree &VPDT) {
   auto LocalComesBefore = [](const VPRecipeBase *A, const VPRecipeBase *B) {
     for (auto &R : *A->getParent()) {
       if (&R == A)
@@ -573,7 +573,7 @@ static bool dominates(const VPRecipeBase *A, const VPRecipeBase *B,
     ParentA = RegionA->getExiting();
   if (RegionB)
     ParentB = RegionB->getExiting();
-  return VPDT.dominates(ParentA, ParentB);
+  return VPDT.properlyDominates(ParentA, ParentB);
 }
 
 // Sink users of \p FOR after the recipe defining the previous value \p Previous
@@ -592,7 +592,7 @@ sinkRecurrenceUsersAfterPrevious(VPFirstOrderRecurrencePHIRecipe *FOR,
         "The previous value cannot depend on the users of the recurrence phi.");
     if (isa<VPHeaderPHIRecipe>(SinkCandidate) ||
         !Seen.insert(SinkCandidate).second ||
-        dominates(Previous, SinkCandidate, VPDT))
+        properlyDominates(Previous, SinkCandidate, VPDT))
       return;
 
     WorkList.push_back(SinkCandidate);
@@ -613,7 +613,7 @@ sinkRecurrenceUsersAfterPrevious(VPFirstOrderRecurrencePHIRecipe *FOR,
   // Keep recipes to sink ordered by dominance so earlier instructions are
   // processed first.
   sort(WorkList, [&VPDT](const VPRecipeBase *A, const VPRecipeBase *B) {
-    return dominates(A, B, VPDT);
+    return properlyDominates(A, B, VPDT);
   });
 
   for (VPRecipeBase *SinkCandidate : WorkList) {