LoopVectorizer: Fix an endless loop in the code that looks for reductions.

The bug was in the code that detects PHIs in if-then-else block sequence.

PR14701.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171008 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 44 insertions, 0 deletions

diff --git a/test/Transforms/LoopVectorize/2012-10-20-infloop.ll b/test/Transforms/LoopVectorize/2012-10-20-infloop.ll
index 0176c9a..da1abc6 100644
--- a/test/Transforms/LoopVectorize/2012-10-20-infloop.ll
+++ b/test/Transforms/LoopVectorize/2012-10-20-infloop.ll
@@ -25,3 +25,47 @@ for.body:                                         ; preds = %for.body, %entry
 for.end:                                          ; preds = %for.body
  unreachable
 }
+
+;PR14701
+define void @start_model_rare() nounwind uwtable ssp {
+entry:
+  br i1 undef, label %return, label %if.end
+
+if.end:                                           ; preds = %entry
+  br i1 undef, label %cond.false, label %cond.true
+
+cond.true:                                        ; preds = %if.end
+  unreachable
+
+cond.false:                                       ; preds = %if.end
+  br i1 undef, label %cond.false28, label %cond.true20
+
+cond.true20:                                      ; preds = %cond.false
+  unreachable
+
+cond.false28:                                     ; preds = %cond.false
+  br label %for.body40
+
+for.body40:                                       ; preds = %for.inc50, %cond.false28
+  %indvars.iv123 = phi i64 [ 3, %cond.false28 ], [ %indvars.iv.next124, %for.inc50 ]
+  %step.0121 = phi i32 [ 1, %cond.false28 ], [ %step.1, %for.inc50 ]
+  br i1 undef, label %if.then46, label %for.inc50
+
+if.then46:                                        ; preds = %for.body40
+  %inc47 = add nsw i32 %step.0121, 1
+  br label %for.inc50
+
+for.inc50:                                        ; preds = %if.then46, %for.body40
+  %k.1 = phi i32 [ undef, %for.body40 ], [ %inc47, %if.then46 ]
+  %step.1 = phi i32 [ %step.0121, %for.body40 ], [ %inc47, %if.then46 ]
+  %indvars.iv.next124 = add i64 %indvars.iv123, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next124 to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, 256
+  br i1 %exitcond, label %for.end52, label %for.body40
+
+for.end52:                                        ; preds = %for.inc50
+  unreachable
+
+return:                                           ; preds = %entry
+  ret void
+}