[llvm] r323515 - [CallSiteSplitting] Fix infinite loop when recording conditions.

[Florian Hahn via llvm-commits]

Author: fhahn
Date: Fri Jan 26 02:36:50 2018
New Revision: 323515

URL: http://llvm.org/viewvc/llvm-project?rev=323515&view=rev
Log:
[CallSiteSplitting] Fix infinite loop when recording conditions.

Fix infinite loop when recording conditions by correctly marking basic
blocks as visited.

Fixes https://bugs.llvm.org/show_bug.cgi?id=36105

Modified:
    llvm/trunk/lib/Transforms/Scalar/CallSiteSplitting.cpp
    llvm/trunk/test/Transforms/CallSiteSplitting/callsite-no-splitting.ll

Modified: llvm/trunk/lib/Transforms/Scalar/CallSiteSplitting.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CallSiteSplitting.cpp?rev=323515&r1=323514&r2=323515&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/CallSiteSplitting.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/CallSiteSplitting.cpp Fri Jan 26 02:36:50 2018
@@ -140,10 +140,11 @@ static void recordConditions(CallSite CS
   recordCondition(CS, Pred, CS.getInstruction()->getParent(), Conditions);
   BasicBlock *From = Pred;
   BasicBlock *To = Pred;
-  SmallPtrSet<BasicBlock *, 4> Visited = {From};
+  SmallPtrSet<BasicBlock *, 4> Visited;
   while (!Visited.count(From->getSinglePredecessor()) &&
          (From = From->getSinglePredecessor())) {
     recordCondition(CS, From, To, Conditions);
+    Visited.insert(From);
     To = From;
   }
 }

Modified: llvm/trunk/test/Transforms/CallSiteSplitting/callsite-no-splitting.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/CallSiteSplitting/callsite-no-splitting.ll?rev=323515&r1=323514&r2=323515&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/CallSiteSplitting/callsite-no-splitting.ll (original)
+++ llvm/trunk/test/Transforms/CallSiteSplitting/callsite-no-splitting.ll Fri Jan 26 02:36:50 2018
@@ -16,3 +16,27 @@ Tail:
   %r = call i32 @callee(i32* %a, i32 %v, i32 %p)
   ret i32 %r
 }
+
+define void @fn1(i16 %p1) {
+entry:
+  ret void
+}
+
+define void @fn2() {
+  ret void
+
+; Unreachable code below
+
+for.inc:                                          ; preds = %for.inc
+  br i1 undef, label %for.end6, label %for.inc
+
+for.end6:                                         ; preds = %for.inc
+  br i1 undef, label %lor.rhs, label %lor.end
+
+lor.rhs:                                          ; preds = %for.end6
+  br label %lor.end
+
+lor.end:                                          ; preds = %for.end6, %lor.rhs
+  call void @fn1(i16 0)
+  ret void
+}