LSR critical edge splitting fix for PR13756.

llvm-svn: 164147

1 files changed, 41 insertions, 3 deletions

diff --git a/llvm/test/Transforms/LoopStrengthReduce/2011-10-03-CritEdgeMerge.ll b/llvm/test/Transforms/LoopStrengthReduce/2011-10-03-CritEdgeMerge.ll
index a6996a81fb0..af3a53708b4 100644
--- a/llvm/test/Transforms/LoopStrengthReduce/2011-10-03-CritEdgeMerge.ll
+++ b/llvm/test/Transforms/LoopStrengthReduce/2011-10-03-CritEdgeMerge.ll
@@ -1,15 +1,15 @@
 ; RUN: opt -loop-reduce -S < %s | FileCheck %s
 ;
 ; Test LSR's use of SplitCriticalEdge during phi rewriting.
-; Verify that identical edges are merged. rdar://problem/6453893
 
 target triple = "x86-apple-darwin"
 
-; CHECK: @test
+; Verify that identical edges are merged. rdar://problem/6453893
+; CHECK: @test1
 ; CHECK: bb89:
 ; CHECK: phi i8* [ %lsr.iv.next1, %bbA.bb89_crit_edge ], [ %lsr.iv.next1, %bbB.bb89_crit_edge ]{{$}}
 
-define i8* @test() {
+define i8* @test1() {
 entry:
   br label %loop
 
@@ -41,3 +41,41 @@ bb89:
 exit:
   ret i8* %tmp75phi
 }
+
+; Handle single-predecessor phis: PR13756
+; CHECK: @test2
+; CHECK: bb89:
+; CHECK: phi i8* [ %lsr.iv.next1, %bbA ], [ %lsr.iv.next1, %bbA ], [ %lsr.iv.next1, %bbA ]{{$}}
+define i8* @test2() {
+entry:
+  br label %loop
+
+loop:
+  %rec = phi i32 [ %next, %loop ], [ 0, %entry ]
+  %next = add i32 %rec, 1
+  %tmp75 = getelementptr i8* null, i32 %next
+  br i1 false, label %loop, label %loopexit
+
+loopexit:
+  br i1 false, label %bbA, label %bbB
+
+bbA:
+  switch i32 0, label %bb89 [
+    i32 47, label %bb89
+    i32 58, label %bb89
+  ]
+
+bbB:
+  switch i8 0, label %exit [
+    i8 47, label %exit
+    i8 58, label %exit
+  ]
+
+bb89:
+  %tmp75phi = phi i8* [ %tmp75, %bbA ], [ %tmp75, %bbA ], [ %tmp75, %bbA ]
+  br label %exit
+
+exit:
+  %result = phi i8* [ %tmp75phi, %bb89 ], [ %tmp75, %bbB ], [ %tmp75, %bbB ], [ %tmp75, %bbB ]
+  ret i8* %result
+}