Merging r323355:

------------------------------------------------------------------------
r323355 | nha | 2018-01-24 19:02:05 +0100 (Wed, 24 Jan 2018) | 9 lines

Revert r321751, "StructurizeCFG: Fix broken backedge detection"

It causes regressions in various OpenGL test suites.

Keep the test cases introduced by r321751 as XFAIL, and add a test case
for the regression.

Change-Id: I90b4cc354f68cebe5fcef1f2422dc8fe1c6d3514
Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=36015
------------------------------------------------------------------------


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_60@323749 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 81 insertions, 56 deletions

diff --git a/test/Transforms/StructurizeCFG/AMDGPU/backedge-id-bug.ll b/test/Transforms/StructurizeCFG/AMDGPU/backedge-id-bug.ll
index 9cddffdd179..5b5ea676bae 100644
--- a/test/Transforms/StructurizeCFG/AMDGPU/backedge-id-bug.ll
+++ b/test/Transforms/StructurizeCFG/AMDGPU/backedge-id-bug.ll
@@ -1,3 +1,4 @@
+; XFAIL: *
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -mtriple=amdgcn-amd-amdhsa -S -structurizecfg %s | FileCheck %s
 
diff --git a/test/Transforms/StructurizeCFG/bug36015.ll b/test/Transforms/StructurizeCFG/bug36015.ll
new file mode 100644
index 00000000000..24b9c9cdde2
--- /dev/null
+++ b/test/Transforms/StructurizeCFG/bug36015.ll
@@ -0,0 +1,53 @@
+; RUN: opt -S -structurizecfg %s | FileCheck %s
+
+; r321751 introduced a bug where control flow branching from if to exit was
+; not handled properly and instead ended up in an infinite loop.
+define void @bug36015(i32 %cmp0, i32 %count) {
+entry:
+  br label %loop.outer
+
+loop.outer:
+  %ctr.loop.outer = phi i32 [ 0, %entry ], [ %ctr.else, %else ]
+  call void @foo(i32 0)
+  br label %loop.inner
+
+loop.inner:
+  %ctr.loop.inner = phi i32 [ %ctr.loop.outer, %loop.outer ], [ %ctr.if, %if ]
+  call void @foo(i32 1)
+  %cond.inner = icmp eq i32 %cmp0, %ctr.loop.inner
+  br i1 %cond.inner, label %if, label %else
+
+; CHECK: if:
+; CHECK:   %0 = xor i1 %cond.if, true
+; CHECK:   br label %Flow
+if:
+  %ctr.if = add i32 %ctr.loop.inner, 1
+  call void @foo(i32 2)
+  %cond.if = icmp slt i32 %ctr.if, %count
+  br i1 %cond.if, label %loop.inner, label %exit
+
+; CHECK: Flow:
+; CHECK:   %2 = phi i1 [ %0, %if ], [ true, %loop.inner ]
+; CHECK:   %3 = phi i1 [ false, %if ], [ true, %loop.inner ]
+; CHECK:   br i1 %2, label %Flow1, label %loop.inner
+
+; CHECK: Flow1:
+; CHECK:   br i1 %3, label %else, label %Flow2
+
+; CHECK: else:
+; CHECK:   br label %Flow2
+else:
+  %ctr.else = add i32 %ctr.loop.inner, 1
+  call void @foo(i32 3)
+  %cond.else = icmp slt i32 %ctr.else, %count
+  br i1 %cond.else, label %loop.outer, label %exit
+
+; CHECK: Flow2:
+; CHECK:   %6 = phi i1 [ %4, %else ], [ true, %Flow1 ]
+; CHECK:   br i1 %6, label %exit, label %loop.outer
+
+exit:
+  ret void
+}
+
+declare void @foo(i32)
diff --git a/test/Transforms/StructurizeCFG/nested-loop-order.ll b/test/Transforms/StructurizeCFG/nested-loop-order.ll
index 7b5bd5acb62..58634d0d37d 100644
--- a/test/Transforms/StructurizeCFG/nested-loop-order.ll
+++ b/test/Transforms/StructurizeCFG/nested-loop-order.ll
@@ -1,76 +1,32 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -S -structurizecfg %s -o - | FileCheck %s
 
 define void @main(float addrspace(1)* %out) {
-; CHECK-LABEL: @main(
-; CHECK-NEXT:  main_body:
-; CHECK-NEXT:    br label [[LOOP_OUTER:%.*]]
-; CHECK:       LOOP.outer:
-; CHECK-NEXT:    [[TEMP8_0_PH:%.*]] = phi float [ 0.000000e+00, [[MAIN_BODY:%.*]] ], [ [[TMP13:%.*]], [[FLOW3:%.*]] ]
-; CHECK-NEXT:    [[TEMP4_0_PH:%.*]] = phi i32 [ 0, [[MAIN_BODY]] ], [ [[TMP12:%.*]], [[FLOW3]] ]
-; CHECK-NEXT:    br label [[LOOP:%.*]]
-; CHECK:       LOOP:
-; CHECK-NEXT:    [[TMP0:%.*]] = phi i32 [ undef, [[LOOP_OUTER]] ], [ [[TMP12]], [[FLOW:%.*]] ]
-; CHECK-NEXT:    [[TMP1:%.*]] = phi float [ undef, [[LOOP_OUTER]] ], [ [[TMP13]], [[FLOW]] ]
-; CHECK-NEXT:    [[TEMP4_0:%.*]] = phi i32 [ [[TEMP4_0_PH]], [[LOOP_OUTER]] ], [ [[TMP15:%.*]], [[FLOW]] ]
-; CHECK-NEXT:    [[TMP20:%.*]] = add i32 [[TEMP4_0]], 1
-; CHECK-NEXT:    [[TMP22:%.*]] = icmp sgt i32 [[TMP20]], 3
-; CHECK-NEXT:    [[TMP2:%.*]] = xor i1 [[TMP22]], true
-; CHECK-NEXT:    br i1 [[TMP2]], label [[ENDIF:%.*]], label [[FLOW]]
-; CHECK:       Flow2:
-; CHECK-NEXT:    [[TMP3:%.*]] = phi float [ [[TEMP8_0_PH]], [[IF29:%.*]] ], [ [[TMP9:%.*]], [[FLOW1:%.*]] ]
-; CHECK-NEXT:    [[TMP4:%.*]] = phi i32 [ [[TMP20]], [[IF29]] ], [ undef, [[FLOW1]] ]
-; CHECK-NEXT:    [[TMP5:%.*]] = phi i1 [ [[TMP32:%.*]], [[IF29]] ], [ true, [[FLOW1]] ]
-; CHECK-NEXT:    br label [[FLOW]]
-; CHECK:       Flow3:
-; CHECK-NEXT:    br i1 [[TMP16:%.*]], label [[ENDLOOP:%.*]], label [[LOOP_OUTER]]
-; CHECK:       ENDLOOP:
-; CHECK-NEXT:    [[TEMP8_1:%.*]] = phi float [ [[TMP14:%.*]], [[FLOW3]] ]
-; CHECK-NEXT:    [[TMP23:%.*]] = icmp eq i32 [[TMP20]], 3
-; CHECK-NEXT:    [[DOT45:%.*]] = select i1 [[TMP23]], float 0.000000e+00, float 1.000000e+00
-; CHECK-NEXT:    store float [[DOT45]], float addrspace(1)* [[OUT:%.*]]
-; CHECK-NEXT:    ret void
-; CHECK:       ENDIF:
-; CHECK-NEXT:    [[TMP31:%.*]] = icmp sgt i32 [[TMP20]], 1
-; CHECK-NEXT:    [[TMP6:%.*]] = xor i1 [[TMP31]], true
-; CHECK-NEXT:    br i1 [[TMP6]], label [[ENDIF28:%.*]], label [[FLOW1]]
-; CHECK:       Flow1:
-; CHECK-NEXT:    [[TMP7:%.*]] = phi i32 [ [[TMP20]], [[ENDIF28]] ], [ [[TMP0]], [[ENDIF]] ]
-; CHECK-NEXT:    [[TMP8:%.*]] = phi float [ [[TMP35:%.*]], [[ENDIF28]] ], [ [[TMP1]], [[ENDIF]] ]
-; CHECK-NEXT:    [[TMP9]] = phi float [ [[TMP35]], [[ENDIF28]] ], [ [[TEMP8_0_PH]], [[ENDIF]] ]
-; CHECK-NEXT:    [[TMP10:%.*]] = phi i1 [ [[TMP36:%.*]], [[ENDIF28]] ], [ true, [[ENDIF]] ]
-; CHECK-NEXT:    [[TMP11:%.*]] = phi i1 [ false, [[ENDIF28]] ], [ true, [[ENDIF]] ]
-; CHECK-NEXT:    br i1 [[TMP11]], label [[IF29]], label [[FLOW2:%.*]]
-; CHECK:       IF29:
-; CHECK-NEXT:    [[TMP32]] = icmp sgt i32 [[TMP20]], 2
-; CHECK-NEXT:    br label [[FLOW2]]
-; CHECK:       Flow:
-; CHECK-NEXT:    [[TMP12]] = phi i32 [ [[TMP7]], [[FLOW2]] ], [ [[TMP0]], [[LOOP]] ]
-; CHECK-NEXT:    [[TMP13]] = phi float [ [[TMP8]], [[FLOW2]] ], [ [[TMP1]], [[LOOP]] ]
-; CHECK-NEXT:    [[TMP14]] = phi float [ [[TMP3]], [[FLOW2]] ], [ [[TEMP8_0_PH]], [[LOOP]] ]
-; CHECK-NEXT:    [[TMP15]] = phi i32 [ [[TMP4]], [[FLOW2]] ], [ undef, [[LOOP]] ]
-; CHECK-NEXT:    [[TMP16]] = phi i1 [ [[TMP10]], [[FLOW2]] ], [ true, [[LOOP]] ]
-; CHECK-NEXT:    [[TMP17:%.*]] = phi i1 [ [[TMP5]], [[FLOW2]] ], [ true, [[LOOP]] ]
-; CHECK-NEXT:    br i1 [[TMP17]], label [[FLOW3]], label [[LOOP]]
-; CHECK:       ENDIF28:
-; CHECK-NEXT:    [[TMP35]] = fadd float [[TEMP8_0_PH]], 1.000000e+00
-; CHECK-NEXT:    [[TMP36]] = icmp sgt i32 [[TMP20]], 2
-; CHECK-NEXT:    br label [[FLOW1]]
-;
+
+; CHECK: main_body:
+; CHECK: br label %LOOP.outer
 main_body:
   br label %LOOP.outer
 
+; CHECK: LOOP.outer:
+; CHECK: br label %LOOP
 LOOP.outer:                                       ; preds = %ENDIF28, %main_body
   %temp8.0.ph = phi float [ 0.000000e+00, %main_body ], [ %tmp35, %ENDIF28 ]
   %temp4.0.ph = phi i32 [ 0, %main_body ], [ %tmp20, %ENDIF28 ]
   br label %LOOP
 
+; CHECK: LOOP:
+; br i1 %{{[0-9]+}}, label %ENDIF, label %Flow
 LOOP:                                             ; preds = %IF29, %LOOP.outer
   %temp4.0 = phi i32 [ %temp4.0.ph, %LOOP.outer ], [ %tmp20, %IF29 ]
   %tmp20 = add i32 %temp4.0, 1
   %tmp22 = icmp sgt i32 %tmp20, 3
   br i1 %tmp22, label %ENDLOOP, label %ENDIF
 
+; CHECK: Flow3
+; CHECK: br i1 %{{[0-9]+}}, label %ENDLOOP, label %LOOP.outer
+
+; CHECK: ENDLOOP:
+; CHECK: ret void
 ENDLOOP:                                          ; preds = %ENDIF28, %IF29, %LOOP
   %temp8.1 = phi float [ %temp8.0.ph, %LOOP ], [ %temp8.0.ph, %IF29 ], [ %tmp35, %ENDIF28 ]
   %tmp23 = icmp eq i32 %tmp20, 3
@@ -78,14 +34,29 @@ ENDLOOP:                                          ; preds = %ENDIF28, %IF29, %LO
   store float %.45, float addrspace(1)* %out
   ret void
 
+; CHECK: ENDIF:
+; CHECK: br i1 %tmp31, label %IF29, label %Flow1
 ENDIF:                                            ; preds = %LOOP
   %tmp31 = icmp sgt i32 %tmp20, 1
   br i1 %tmp31, label %IF29, label %ENDIF28
 
+; CHECK: Flow:
+; CHECK: br i1 %{{[0-9]+}}, label %Flow2, label %LOOP
+
+; CHECK: IF29:
+; CHECK: br label %Flow1
 IF29:                                             ; preds = %ENDIF
   %tmp32 = icmp sgt i32 %tmp20, 2
   br i1 %tmp32, label %ENDLOOP, label %LOOP
 
+; CHECK: Flow1:
+; CHECK: br label %Flow
+
+; CHECK: Flow2:
+; CHECK: br i1 %{{[0-9]+}}, label %ENDIF28, label %Flow3
+
+; CHECK: ENDIF28:
+; CHECK: br label %Flow3
 ENDIF28:                                          ; preds = %ENDIF
   %tmp35 = fadd float %temp8.0.ph, 1.0
   %tmp36 = icmp sgt i32 %tmp20, 2