Nick Lewycky's patch.

While hosting instruction check PHI node.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57025 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 604a717..7f41336 100644 (file)
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1051,7 +1051,7 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *BB1) {
   BasicBlock::iterator InsertPos = BI;
   if (InsertPos != BIParent->begin()) 
     --InsertPos;
-  if (InsertPos == BrCond) {
+  if (InsertPos == BrCond && !isa<PHINode>(BrCond)) {
     SmallPtrSet<Instruction *, 4> BB1Insns;
     for(BasicBlock::iterator BB1I = BB1->begin(), BB1E = BB1->end(); 
         BB1I != BB1E; ++BB1I) 

diff --git a/test/Transforms/SimplifyCFG/2008-10-03-SpeculativelyExecuteBeforePHI.ll b/test/Transforms/SimplifyCFG/2008-10-03-SpeculativelyExecuteBeforePHI.ll
new file mode 100644 (file)
index 0000000..a061a82
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/2008-10-03-SpeculativelyExecuteBeforePHI.ll
@@ -0,0 +1,36 @@
+; RUN: llvm-as < %s | opt -simplifycfg
+; PR2855
+
+define i32 @_Z1fPii(i32* %b, i32 %f) nounwind {
+entry:
+       br label %bb
+
+bb:            ; preds = %bb9, %bb7, %bb, %entry
+       %__c2.2 = phi i32 [ undef, %entry ], [ %__c2.1, %bb7 ], [ %__c2.1, %bb9 ]               ; <i32> [#uses=2]
+       %s.0 = phi i32 [ 0, %entry ], [ 0, %bb7 ], [ %2, %bb9 ]         ; <i32> [#uses=1]
+       br label %bb1
+
+bb1:           ; preds = %bb
+       %0 = icmp slt i32 0, %f         ; <i1> [#uses=1]
+       br i1 %0, label %bb3, label %bb6
+
+bb3:           ; preds = %bb1
+       %1 = icmp eq i32 0, 0           ; <i1> [#uses=1]
+       br i1 %1, label %bb6, label %bb5
+
+bb5:           ; preds = %bb3
+       br label %bb7
+
+bb6:           ; preds = %bb3, %bb1
+       %__c2.0 = phi i32 [ 0, %bb3 ], [ %__c2.2, %bb1 ]                ; <i32> [#uses=1]
+       br label %bb7
+
+bb7:           ; preds = %bb6, %bb5
+       %__c2.1 = phi i32 [ 0, %bb5 ], [ %__c2.0, %bb6 ]                ; <i32> [#uses=2]
+       %iftmp.1.0 = phi i1 [ false, %bb5 ], [ true, %bb6 ]             ; <i1> [#uses=1]
+       br i1 %iftmp.1.0, label %bb, label %bb9
+
+bb9:           ; preds = %bb7
+       %2 = add i32 %s.0, 2            ; <i32> [#uses=1]
+       br label %bb
+}