Fix PR2256, yet another miscompilation in simplifycfg of i

multiple return values.

Bill, please pull this into Tak.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50332 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 34 insertions, 3 deletions

diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 7f37b45f2d..b584e13876 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1365,10 +1365,11 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
 
           // If the return instruction returns a value, and if the value was a
           // PHI node in "BB", propagate the right value into the return.
-          if (NewRet->getNumOperands() == 1)
-            if (PHINode *PN = dyn_cast<PHINode>(NewRet->getOperand(0)))
+          for (unsigned i = 0, e = NewRet->getNumOperands(); i != e; ++i)
+            if (PHINode *PN = dyn_cast<PHINode>(NewRet->getOperand(i)))
               if (PN->getParent() == BB)
-                NewRet->setOperand(0, PN->getIncomingValueForBlock(Pred));
+                NewRet->setOperand(i, PN->getIncomingValueForBlock(Pred));
+          
           // Update any PHI nodes in the returning block to realize that we no
           // longer branch to them.
           BB->removePredecessor(Pred);
diff --git a/test/Transforms/SimplifyCFG/2008-04-27-MultipleReturnCrash.ll b/test/Transforms/SimplifyCFG/2008-04-27-MultipleReturnCrash.ll
new file mode 100644
index 0000000000..a370b95210
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/2008-04-27-MultipleReturnCrash.ll
@@ -0,0 +1,30 @@
+; RUN: llvm-as < %s | opt -simplifycfg -disable-output
+; PR2256
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-mingw32"
+
+define { x86_fp80, x86_fp80 } @catanl({ x86_fp80, x86_fp80 }* byval  %Z, i1 %cond) nounwind  {
+bb:		; preds = %entry
+	br i1  %cond, label %bb48, label %bb40
+
+bb40:		; preds = %bb
+	store i32 34, i32* null, align 4
+	br label %bb196
+
+bb48:		; preds = %bb.bb48_crit_edge, %entry.bb48_crit_edge
+	%tmp53 = icmp eq i32 0, 1280		; <i1> [#uses=1]
+	br i1 %tmp53, label %bb56, label %bb174
+
+bb56:		; preds = %bb48
+	%iftmp.0.0 = select i1 false, x86_fp80 0xK3FFFC90FDAA22168C235, x86_fp80 0xKBFFFC90FDAA22168C235		; <x86_fp80> [#uses=0]
+	br label %bb196
+
+
+bb174:		; preds = %bb144, %bb114
+	%tmp191 = mul x86_fp80 0xK00000000000000000000, 0xK3FFE8000000000000000		; <x86_fp80> [#uses=1]
+	br label %bb196
+
+bb196:		; preds = %bb174, %bb56, %bb40
+	%Res.1.0 = phi x86_fp80 [ 0xK7FFF8000000000000000, %bb40 ], [ %tmp191, %bb174 ], [ 0xK00000000000000000000, %bb56 ]		; <x86_fp80> [#uses=1]
+	ret x86_fp80 0xK00000000000000000000, x86_fp80 %Res.1.0
+}