Index: lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- lib/Transforms/Vectorize/LoopVectorize.cpp
+++ lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -450,10 +450,10 @@
   /// vectorizing this phi node.
   void fixReduction(PHINode *Phi);
 
-  /// \brief The Loop exit block may have single value PHI nodes where the
-  /// incoming value is 'Undef'. While vectorizing we only handled real values
-  /// that were defined inside the loop. Here we fix the 'undef case'.
-  /// See PR14725.
+  /// \brief The Loop exit block may have single value PHI nodes with some
+  /// incoming value. While vectorizing we only handled real values
+  /// that were defined inside the loop and we should have one value for
+  /// each predecessor of its parent basic block. See PR14725.
   void fixLCSSAPHIs();
 
   /// Iteratively sink the scalarized operands of a predicated instruction into
@@ -4346,7 +4346,7 @@
     if (!LCSSAPhi)
       break;
     if (LCSSAPhi->getNumIncomingValues() == 1)
-      LCSSAPhi->addIncoming(UndefValue::get(LCSSAPhi->getType()),
+        LCSSAPhi->addIncoming(LCSSAPhi->getIncomingValue(0),
                             LoopMiddleBlock);
   }
 }
Index: test/Transforms/LoopVectorize/pr32859.ll
===================================================================
--- /dev/null
+++ test/Transforms/LoopVectorize/pr32859.ll
@@ -0,0 +1,154 @@
+; RUN: opt < %s -inline -sroa -jump-threading -lcssa -loop-rotate -loop-vectorize -loop-unroll -S 2>&1 | FileCheck %s
+
+; CHECK-LABEL: for.cond.preheader:
+; CHECK: %e.0.ph = phi i32 [ 0, %vector.body ], [ 0, %for.cond.preheader.loopexit ]
+; CHECK-NEXT: br label %for.body
+
+@a = global i32 1, align 4
+@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+
+; Function Attrs: nounwind uwtable
+define void @foo() #0 {
+entry:
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  %d = alloca i32, align 4
+  %0 = bitcast i32* %b to i8*
+  call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #3
+  %1 = bitcast i32* %c to i8*
+  call void @llvm.lifetime.start.p0i8(i64 4, i8* %1) #3
+  %2 = bitcast i32* %d to i8*
+  call void @llvm.lifetime.start.p0i8(i64 4, i8* %2) #3
+  store i32 0, i32* %c, align 4, !tbaa !1
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc4, %entry
+  %3 = load i32, i32* %c, align 4, !tbaa !1
+  %cmp = icmp slt i32 %3, 16
+  br i1 %cmp, label %for.body, label %for.end6
+
+for.body:                                         ; preds = %for.cond
+  %4 = load i32, i32* %c, align 4, !tbaa !1
+  store i32 %4, i32* %b, align 4, !tbaa !1
+  store i32 0, i32* %d, align 4, !tbaa !1
+  br label %for.cond1
+
+for.cond1:                                        ; preds = %for.inc, %for.body
+  %5 = load i32, i32* %d, align 4, !tbaa !1
+  %cmp2 = icmp slt i32 %5, 3
+  br i1 %cmp2, label %for.body3, label %for.end
+
+for.body3:                                        ; preds = %for.cond1
+  %6 = load i32, i32* %b, align 4, !tbaa !1
+  %and = and i32 %6, 1
+  %tobool = icmp ne i32 %and, 0
+  br i1 %tobool, label %if.then, label %if.end
+
+if.then:                                          ; preds = %for.body3
+  store i32 0, i32* %b, align 4, !tbaa !1
+  br label %if.end
+
+if.end:                                           ; preds = %if.then, %for.body3
+  br label %for.inc
+
+for.inc:                                          ; preds = %if.end
+  %7 = load i32, i32* %d, align 4, !tbaa !1
+  %inc = add nsw i32 %7, 1
+  store i32 %inc, i32* %d, align 4, !tbaa !1
+  br label %for.cond1
+
+for.end:                                          ; preds = %for.cond1
+  br label %for.inc4
+
+for.inc4:                                         ; preds = %for.end
+  %8 = load i32, i32* %c, align 4, !tbaa !1
+  %inc5 = add nsw i32 %8, 1
+  store i32 %inc5, i32* %c, align 4, !tbaa !1
+  br label %for.cond
+
+for.end6:                                         ; preds = %for.cond
+  %9 = bitcast i32* %d to i8*
+  call void @llvm.lifetime.end.p0i8(i64 4, i8* %9) #3
+  %10 = bitcast i32* %c to i8*
+  call void @llvm.lifetime.end.p0i8(i64 4, i8* %10) #3
+  %11 = bitcast i32* %b to i8*
+  call void @llvm.lifetime.end.p0i8(i64 4, i8* %11) #3
+  ret void
+}
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #1
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #1
+
+; Function Attrs: nounwind uwtable
+define i32 @main() #0 {
+entry:
+  %retval = alloca i32, align 4
+  %e = alloca i32, align 4
+  %f = alloca i32, align 4
+  store i32 0, i32* %retval, align 4
+  %0 = bitcast i32* %e to i8*
+  call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #3
+  call void @foo()
+  store i32 0, i32* %e, align 4, !tbaa !1
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc, %entry
+  %1 = load i32, i32* %e, align 4, !tbaa !1
+  %cmp = icmp slt i32 %1, 10
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  %2 = bitcast i32* %f to i8*
+  call void @llvm.lifetime.start.p0i8(i64 4, i8* %2) #3
+  %3 = load i32, i32* @a, align 4, !tbaa !1
+  %div = sdiv i32 1, %3
+  store i32 %div, i32* %f, align 4, !tbaa !1
+  %4 = load i32, i32* %f, align 4, !tbaa !1
+  %tobool = icmp ne i32 %4, 0
+  br i1 %tobool, label %land.lhs.true, label %lor.rhs
+
+land.lhs.true:                                    ; preds = %for.body
+  %5 = load i32, i32* %f, align 4, !tbaa !1
+  %cmp1 = icmp eq i32 %5, 1
+  br i1 %cmp1, label %lor.end, label %lor.rhs
+
+lor.rhs:                                          ; preds = %land.lhs.true, %for.body
+  br label %lor.end
+
+lor.end:                                          ; preds = %lor.rhs, %land.lhs.true
+  %6 = phi i1 [ true, %land.lhs.true ], [ false, %lor.rhs ]
+  %lor.ext = zext i1 %6 to i32
+  %call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i32 %lor.ext)
+  %7 = bitcast i32* %f to i8*
+  call void @llvm.lifetime.end.p0i8(i64 4, i8* %7) #3
+  br label %for.inc
+
+for.inc:                                          ; preds = %lor.end
+  %8 = load i32, i32* %e, align 4, !tbaa !1
+  %inc = add nsw i32 %8, 1
+  store i32 %inc, i32* %e, align 4, !tbaa !1
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  %9 = bitcast i32* %e to i8*
+  call void @llvm.lifetime.end.p0i8(i64 4, i8* %9) #3
+  ret i32 0
+}
+
+declare i32 @printf(i8*, ...) #2
+
+attributes #0 = { nounwind uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind }
+attributes #2 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #3 = { nounwind }
+
+!llvm.ident = !{!0}
+
+!0 = !{!"clang version 5.0.0 (http://llvm.org/git/clang.git 08c94e4bd75c5a2e4de5ea108d98739f5179dbeb) (http://llvm.org/git/llvm.git 7d66f52694bdfabf0081a1d40b99fca0c189a988)"}
+!1 = !{!2, !2, i64 0}
+!2 = !{!"int", !3, i64 0}
+!3 = !{!"omnipotent char", !4, i64 0}
+!4 = !{!"Simple C/C++ TBAA"}