From cf19403e392cb6db8fcdd626c805d24d958dd5d1 Mon Sep 17 00:00:00 2001
From: Michael Zolotukhin <mzolotukhin@apple.com>
Date: Fri, 31 Oct 2014 22:28:03 +0000
Subject: [PATCH] Correctly update dom-tree after loop vectorizer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221009 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Vectorize/LoopVectorize.cpp    |   2 +-
 .../LoopVectorize/incorrect-dom-info.ll       | 142 ++++++++++++++++++
 2 files changed, 143 insertions(+), 1 deletion(-)
 create mode 100644 test/Transforms/LoopVectorize/incorrect-dom-info.ll

diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
index a62c0f9f002..17e11724183 100644
--- a/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -3428,7 +3428,7 @@ void InnerLoopVectorizer::updateAnalysis() {
   DT->addNewBlock(LoopMiddleBlock, LoopBypassBlocks[1]);
   DT->addNewBlock(LoopScalarPreHeader, LoopBypassBlocks[0]);
   DT->changeImmediateDominator(LoopScalarBody, LoopScalarPreHeader);
-  DT->changeImmediateDominator(LoopExitBlock, LoopMiddleBlock);
+  DT->changeImmediateDominator(LoopExitBlock, LoopBypassBlocks[0]);
 
   DEBUG(DT->verifyDomTree());
 }
diff --git a/test/Transforms/LoopVectorize/incorrect-dom-info.ll b/test/Transforms/LoopVectorize/incorrect-dom-info.ll
new file mode 100644
index 00000000000..624ee7e5059
--- /dev/null
+++ b/test/Transforms/LoopVectorize/incorrect-dom-info.ll
@@ -0,0 +1,142 @@
+; This test is based on one of benchmarks from SPEC2006. It exposes a bug with
+; incorrect updating of the dom-tree.
+; RUN: opt < %s  -loop-vectorize -verify-dom-info
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+
+@PL_utf8skip = external constant [0 x i8]
+
+; Function Attrs: nounwind ssp uwtable
+define void @Perl_pp_quotemeta() #0 {
+  %len = alloca i64, align 8
+  br i1 undef, label %2, label %1
+
+; <label>:1                                       ; preds = %0
+  br label %3
+
+; <label>:2                                       ; preds = %0
+  br label %3
+
+; <label>:3                                       ; preds = %2, %1
+  br i1 undef, label %34, label %4
+
+; <label>:4                                       ; preds = %3
+  br i1 undef, label %5, label %6
+
+; <label>:5                                       ; preds = %4
+  br label %6
+
+; <label>:6                                       ; preds = %5, %4
+  br i1 undef, label %7, label %8
+
+; <label>:7                                       ; preds = %6
+  br label %8
+
+; <label>:8                                       ; preds = %7, %6
+  br i1 undef, label %.preheader, label %9
+
+.preheader:                                       ; preds = %9, %8
+  br i1 undef, label %.loopexit, label %.lr.ph
+
+; <label>:9                                       ; preds = %8
+  br i1 undef, label %thread-pre-split.preheader, label %.preheader
+
+thread-pre-split.preheader:                       ; preds = %9
+  br i1 undef, label %thread-pre-split._crit_edge, label %.lr.ph21
+
+.thread-pre-split.loopexit_crit_edge:             ; preds = %19
+  %scevgep.sum = xor i64 %umax, -1
+  %scevgep45 = getelementptr i8* %d.020, i64 %scevgep.sum
+  br label %thread-pre-split.loopexit
+
+thread-pre-split.loopexit:                        ; preds = %11, %.thread-pre-split.loopexit_crit_edge
+  %d.1.lcssa = phi i8* [ %scevgep45, %.thread-pre-split.loopexit_crit_edge ], [ %d.020, %11 ]
+  br i1 false, label %thread-pre-split._crit_edge, label %.lr.ph21
+
+.lr.ph21:                                         ; preds = %26, %thread-pre-split.loopexit, %thread-pre-split.preheader
+  %d.020 = phi i8* [ undef, %26 ], [ %d.1.lcssa, %thread-pre-split.loopexit ], [ undef, %thread-pre-split.preheader ]
+  %10 = phi i64 [ %28, %26 ], [ undef, %thread-pre-split.loopexit ], [ undef, %thread-pre-split.preheader ]
+  br i1 undef, label %11, label %22
+
+; <label>:11                                      ; preds = %.lr.ph21
+  %12 = getelementptr inbounds [0 x i8]* @PL_utf8skip, i64 0, i64 undef
+  %13 = load i8* %12, align 1
+  %14 = zext i8 %13 to i64
+  %15 = icmp ugt i64 %14, %10
+  %. = select i1 %15, i64 %10, i64 %14
+  br i1 undef, label %thread-pre-split.loopexit, label %.lr.ph28
+
+.lr.ph28:                                         ; preds = %11
+  %16 = xor i64 %10, -1
+  %17 = xor i64 %14, -1
+  %18 = icmp ugt i64 %16, %17
+  %umax = select i1 %18, i64 %16, i64 %17
+  br label %19
+
+; <label>:19                                      ; preds = %19, %.lr.ph28
+  %ulen.126 = phi i64 [ %., %.lr.ph28 ], [ %20, %19 ]
+  %20 = add i64 %ulen.126, -1
+  %21 = icmp eq i64 %20, 0
+  br i1 %21, label %.thread-pre-split.loopexit_crit_edge, label %19
+
+; <label>:22                                      ; preds = %.lr.ph21
+  br i1 undef, label %26, label %23
+
+; <label>:23                                      ; preds = %22
+  br i1 undef, label %26, label %24
+
+; <label>:24                                      ; preds = %23
+  br i1 undef, label %26, label %25
+
+; <label>:25                                      ; preds = %24
+  br label %26
+
+; <label>:26                                      ; preds = %25, %24, %23, %22
+  %27 = load i64* %len, align 8
+  %28 = add i64 %27, -1
+  br i1 undef, label %thread-pre-split._crit_edge, label %.lr.ph21
+
+thread-pre-split._crit_edge:                      ; preds = %26, %thread-pre-split.loopexit, %thread-pre-split.preheader
+  br label %.loopexit
+
+.lr.ph:                                           ; preds = %33, %.preheader
+  br i1 undef, label %29, label %thread-pre-split5
+
+; <label>:29                                      ; preds = %.lr.ph
+  br i1 undef, label %33, label %30
+
+; <label>:30                                      ; preds = %29
+  br i1 undef, label %33, label %31
+
+thread-pre-split5:                                ; preds = %.lr.ph
+  br i1 undef, label %33, label %31
+
+; <label>:31                                      ; preds = %thread-pre-split5, %30
+  br i1 undef, label %33, label %32
+
+; <label>:32                                      ; preds = %31
+  br label %33
+
+; <label>:33                                      ; preds = %32, %31, %thread-pre-split5, %30, %29
+  br i1 undef, label %.loopexit, label %.lr.ph
+
+.loopexit:                                        ; preds = %33, %thread-pre-split._crit_edge, %.preheader
+  br label %35
+
+; <label>:34                                      ; preds = %3
+  br label %35
+
+; <label>:35                                      ; preds = %34, %.loopexit
+  br i1 undef, label %37, label %36
+
+; <label>:36                                      ; preds = %35
+  br label %37
+
+; <label>:37                                      ; preds = %36, %35
+  ret void
+}
+
+attributes #0 = { nounwind ssp uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.ident = !{!0}
+
+!0 = metadata !{metadata !"clang version 3.6.0 "}