If succ has succ itself as one of the predecessors then do

not merge current bb and succ even if bb's terminator is
unconditional branch to succ.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45305 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 1305fd92c769fdca67bdabd5b3a67f751a4b6977..ee283a04c588a3775c783bfd4cb3117f3914f6a6 100644 (file)
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -110,10 +110,10 @@ static bool CanPropagatePredecessorsForPHIs(BasicBlock *BB, BasicBlock *Succ) {
   // update the PHI nodes correctly.
   if (!isa<PHINode>(BB->begin()) || Succ->getSinglePredecessor()) return true;
 
-  // If the predecessors of Succ are only BB and Succ itself, handle it.
+  // If the predecessors of Succ are only BB, handle it.
   bool IsSafe = true;
   for (pred_iterator PI = pred_begin(Succ), E = pred_end(Succ); PI != E; ++PI)
-    if (*PI != Succ && *PI != BB) {
+    if (*PI != BB) {
       IsSafe = false;
       break;
     }

diff --git a/test/Transforms/SimplifyCFG/2007-12-21-Crash.ll b/test/Transforms/SimplifyCFG/2007-12-21-Crash.ll
new file mode 100644 (file)
index 0000000..31a22f5
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/2007-12-21-Crash.ll
@@ -0,0 +1,60 @@
+; RUN:  llvm-as < %s | opt -std-compile-opts -disable-output
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+define i32 @bork() {
+entry:
+       %retval = alloca i32            ; <i32*> [#uses=2]
+       %opt = alloca i32               ; <i32*> [#uses=3]
+       %undo = alloca i32              ; <i32*> [#uses=3]
+       %tmp = alloca i32               ; <i32*> [#uses=3]
+       %"alloca point" = bitcast i32 0 to i32          ; <i32> [#uses=0]
+       store i32 0, i32* %undo, align 4
+       br label %bb5
+
+bb:            ; preds = %bb5
+       %tmp1 = load i32* %opt, align 4         ; <i32> [#uses=1]
+       switch i32 %tmp1, label %bb4 [
+                i32 102, label %bb3
+                i32 110, label %bb2
+       ]
+
+bb2:           ; preds = %bb
+       store i32 1, i32* %undo, align 4
+       br label %bb3
+
+bb3:           ; preds = %bb2, %bb
+       br label %bb5
+
+bb4:           ; preds = %bb
+       store i32 258, i32* %tmp, align 4
+       br label %bb13
+
+bb5:           ; preds = %bb3, %entry
+       %tmp6 = call i32 (...)* @foo( ) nounwind                ; <i32> [#uses=1]
+       store i32 %tmp6, i32* %opt, align 4
+       %tmp7 = load i32* %opt, align 4         ; <i32> [#uses=1]
+       %tmp8 = icmp ne i32 %tmp7, -1           ; <i1> [#uses=1]
+       %tmp89 = zext i1 %tmp8 to i8            ; <i8> [#uses=1]
+       %toBool = icmp ne i8 %tmp89, 0          ; <i1> [#uses=1]
+       br i1 %toBool, label %bb, label %bb10
+
+bb10:          ; preds = %bb5
+       %tmp11 = load i32* %undo, align 4               ; <i32> [#uses=1]
+       %tmp12 = call i32 (...)* @bar( i32 %tmp11 ) nounwind            ; <i32> [#uses=0]
+       store i32 1, i32* %tmp, align 4
+       br label %bb13
+
+bb13:          ; preds = %bb10, %bb4
+       %tmp14 = load i32* %tmp, align 4                ; <i32> [#uses=1]
+       store i32 %tmp14, i32* %retval, align 4
+       br label %return
+
+return:                ; preds = %bb13
+       %retval15 = load i32* %retval           ; <i32> [#uses=1]
+       ret i32 %retval15
+}
+
+declare i32 @foo(...)
+
+declare i32 @bar(...)