[llvm] r354656 - [MemorySSA & LoopPassManager] Resolve PR40038.

[Alina Sbirlea via llvm-commits]

Author: asbirlea
Date: Thu Feb 21 23:18:37 2019
New Revision: 354656

URL: http://llvm.org/viewvc/llvm-project?rev=354656&view=rev
Log:
[MemorySSA & LoopPassManager] Resolve PR40038.

The correct edge being deleted is not to the unswitched exit block, but to the
original block before it was split. That's the key in the map, not the
value.
The insert is correct. The new edge is to the .split block.

The splitting turns OriginalBB into:
OriginalBB -> OriginalBB.split.
Assuming the orignal CFG edge: ParentBB->OriginalBB, we must now delete
ParentBB->OriginalBB, not ParentBB->OriginalBB.split.

Added:
    llvm/trunk/test/Analysis/MemorySSA/pr40038.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp?rev=354656&r1=354655&r2=354656&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp Thu Feb 21 23:18:37 2019
@@ -793,9 +793,8 @@ static bool unswitchTrivialSwitch(Loop &
     DTUpdates.push_back({DT.Insert, OldPH, UnswitchedExitBB});
   }
   for (auto SplitUnswitchedPair : SplitExitBBMap) {
-    auto *UnswitchedBB = SplitUnswitchedPair.second;
-    DTUpdates.push_back({DT.Delete, ParentBB, UnswitchedBB});
-    DTUpdates.push_back({DT.Insert, OldPH, UnswitchedBB});
+    DTUpdates.push_back({DT.Delete, ParentBB, SplitUnswitchedPair.first});
+    DTUpdates.push_back({DT.Insert, OldPH, SplitUnswitchedPair.second});
   }
   DT.applyUpdates(DTUpdates);
 

Added: llvm/trunk/test/Analysis/MemorySSA/pr40038.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/MemorySSA/pr40038.ll?rev=354656&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/MemorySSA/pr40038.ll (added)
+++ llvm/trunk/test/Analysis/MemorySSA/pr40038.ll Thu Feb 21 23:18:37 2019
@@ -0,0 +1,83 @@
+; REQUIRES: asserts
+; RUN: opt -S -mtriple=systemz-unknown -mcpu=z13  -O3 -enable-mssa-loop-dependency -enable-simple-loop-unswitch -verify-memoryssa  < %s | FileCheck %s
+
+target datalayout = "E-m:e-i1:8:16-i8:8:16-i64:64-f128:64-v128:64-a:8:16-n32:64"
+target triple = "s390x-ibm-linux"
+
+ at g_80 = external dso_local global i32, align 4
+ at g_1683 = external dso_local global i32, align 4
+ at 0 = internal global [7 x i8] c"\00\EE\00\00\EE\00\00", align 2
+
+; Function Attrs: nounwind
+; CHECK-LABEL: @main
+define dso_local void @main() #0 {
+bb:
+  call void @func_1()
+  unreachable
+}
+
+; Function Attrs: nounwind
+define dso_local void @func_1() #0 {
+bb:
+  call void @func_2()
+  unreachable
+}
+
+; Function Attrs: nounwind
+define dso_local void @func_2() #0 {
+bb:
+  %tmp = alloca i32, align 4
+  store i32 0, i32* @g_80, align 4, !tbaa !1
+  br label %bb1
+
+bb1:                                              ; preds = %bb15, %bb
+  %tmp2 = load i32, i32* @g_80, align 4, !tbaa !1
+  %tmp3 = icmp sle i32 %tmp2, 6
+  br i1 %tmp3, label %bb4, label %bb18
+
+bb4:                                              ; preds = %bb1
+  %tmp5 = load i32, i32* @g_1683, align 4, !tbaa !1
+  %tmp6 = sext i32 %tmp5 to i64
+  %tmp7 = getelementptr inbounds [7 x i8], [7 x i8]* @0, i64 0, i64 %tmp6
+  %tmp8 = load i8, i8* %tmp7, align 1, !tbaa !5
+  %tmp9 = icmp ne i8 %tmp8, 0
+  br i1 %tmp9, label %bb10, label %bb11
+
+bb10:                                             ; preds = %bb4
+  store i32 82, i32* %tmp, align 4
+  br label %bb12
+
+bb11:                                             ; preds = %bb4
+  store i32 0, i32* %tmp, align 4
+  br label %bb12
+
+bb12:                                             ; preds = %bb11, %bb10
+  %tmp13 = load i32, i32* %tmp, align 4
+  %tmp14 = icmp ult i32 %tmp13, 1
+  br i1 %tmp14, label %bb15, label %bb18
+
+bb15:                                             ; preds = %bb12
+  %tmp16 = load i32, i32* @g_80, align 4, !tbaa !1
+  %tmp17 = add nsw i32 %tmp16, 1
+  store i32 %tmp17, i32* @g_80, align 4, !tbaa !1
+  br label %bb1
+
+bb18:                                             ; preds = %bb12, %bb1
+  call void @llvm.trap()
+  unreachable
+}
+
+; Function Attrs: cold noreturn nounwind
+declare void @llvm.trap() #1
+
+attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "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"="z13" "target-features"="+transactional-execution,+vector" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { cold noreturn nounwind }
+
+!llvm.ident = !{!0}
+
+!0 = !{!"clang version 8.0.0 (http://llvm.org/git/clang.git a674a04e68bcf09f9a0423f3f589589596bc01a6) (http://llvm.org/git/llvm.git 1fe1ffe00e034128d1c5504254fdd4742f48bb9a)"}
+!1 = !{!2, !2, i64 0}
+!2 = !{!"int", !3, i64 0}
+!3 = !{!"omnipotent char", !4, i64 0}
+!4 = !{!"Simple C/C++ TBAA"}
+!5 = !{!3, !3, i64 0}