[llvm-branch-commits] [llvm] a14945c - [SimplifyCFG] SimplifyEqualityComparisonWithOnlyPredecessor(): really don't delete DomTree edges multiple times

[Roman Lebedev via llvm-branch-commits]

Author: Roman Lebedev
Date: 2021-01-06T01:52:39+03:00
New Revision: a14945c1db614261a6f8d5d199e246d78f51e977

URL: https://github.com/llvm/llvm-project/commit/a14945c1db614261a6f8d5d199e246d78f51e977
DIFF: https://github.com/llvm/llvm-project/commit/a14945c1db614261a6f8d5d199e246d78f51e977.diff

LOG: [SimplifyCFG] SimplifyEqualityComparisonWithOnlyPredecessor(): really don't delete DomTree edges multiple times

Added: 
    

Modified: 
    llvm/lib/Transforms/Utils/SimplifyCFG.cpp
    llvm/test/Transforms/SimplifyCFG/SimplifyEqualityComparisonWithOnlyPredecessor-domtree-preservation-edgecase.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index a433d04f2422..3fbc22a85be4 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -994,7 +994,8 @@ bool SimplifyCFGOpt::SimplifyEqualityComparisonWithOnlyPredecessor(
   BasicBlock *CheckEdge = TheRealDest;
   for (BasicBlock *Succ : successors(TIBB))
     if (Succ != CheckEdge) {
-      RemovedSuccs.insert(Succ);
+      if (Succ != TheRealDest)
+        RemovedSuccs.insert(Succ);
       Succ->removePredecessor(TIBB);
     } else
       CheckEdge = nullptr;

diff  --git a/llvm/test/Transforms/SimplifyCFG/SimplifyEqualityComparisonWithOnlyPredecessor-domtree-preservation-edgecase.ll b/llvm/test/Transforms/SimplifyCFG/SimplifyEqualityComparisonWithOnlyPredecessor-domtree-preservation-edgecase.ll
index d6b9ea7f52c7..617cd062652e 100644
--- a/llvm/test/Transforms/SimplifyCFG/SimplifyEqualityComparisonWithOnlyPredecessor-domtree-preservation-edgecase.ll
+++ b/llvm/test/Transforms/SimplifyCFG/SimplifyEqualityComparisonWithOnlyPredecessor-domtree-preservation-edgecase.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=0 < %s | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 < %s | FileCheck %s
 
 declare void @zzz()