third bug from PR6119: the xor dupe extension allows

for arbitrary terminators in predecessors, don't assume
it is a conditional or uncond branch.  The testcase shows
an example where they can happen with switches.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94323 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index a7b4d157fcdbb35ed06235594c8bd15923553e9c..3eff3d8d23d4d775ff1ce068ffac104de326718c 100644 (file)
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -1424,9 +1424,9 @@ bool JumpThreading::DuplicateCondBranchOnPHIIntoPred(BasicBlock *BB,
   
   // Unless PredBB ends with an unconditional branch, split the edge so that we
   // can just clone the bits from BB into the end of the new PredBB.
-  BranchInst *OldPredBranch = cast<BranchInst>(PredBB->getTerminator());
+  BranchInst *OldPredBranch = dyn_cast<BranchInst>(PredBB->getTerminator());
   
-  if (!OldPredBranch->isUnconditional()) {
+  if (OldPredBranch == 0 || !OldPredBranch->isUnconditional()) {
     PredBB = SplitEdge(PredBB, BB, this);
     OldPredBranch = cast<BranchInst>(PredBB->getTerminator());
   }

diff --git a/test/Transforms/JumpThreading/crash.ll b/test/Transforms/JumpThreading/crash.ll
index ff980ffcc62402bf1647f4573cebf798965134d1..cf292df0f716ec112e699432ce70987e0d1e21fb 100644 (file)
--- a/test/Transforms/JumpThreading/crash.ll
+++ b/test/Transforms/JumpThreading/crash.ll
@@ -286,3 +286,30 @@ for.body:                                         ; preds = %for.cond
   br label %for.cond
 }
 
+; PR6119
+define i32 @test10(i32 %action, i32 %type) nounwind {
+entry:
+  %cmp2 = icmp eq i32 %type, 0                    ; <i1> [#uses=1]
+  switch i32 %action, label %lor.rhs [
+    i32 1, label %if.then
+    i32 0, label %lor.end
+  ]
+
+if.then:                                          ; preds = %for.cond, %lor.end, %entry
+  ret i32 undef
+
+lor.rhs:                                          ; preds = %entry
+  %cmp101 = icmp eq i32 %action, 2                ; <i1> [#uses=1]
+  br label %lor.end
+
+lor.end:                                          ; preds = %lor.rhs, %entry
+  %0 = phi i1 [ %cmp101, %lor.rhs ], [ true, %entry ] ; <i1> [#uses=1]
+  %cmp103 = xor i1 %cmp2, %0                      ; <i1> [#uses=1]
+  br i1 %cmp103, label %for.cond, label %if.then
+
+for.cond:                                         ; preds = %for.body, %lor.end
+  br i1 undef, label %if.then, label %for.body
+
+for.body:                                         ; preds = %for.cond
+  br label %for.cond
+}