[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion

Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here:

A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins.
B) Instructions in the middle block have different line numbers which give the impression of another iteration.

In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks.

I have set up a separate review D61933 for a fix which is required for this patch.

Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel, jmorse

Reviewed By: hfinkel, jmorse

Subscribers: jmorse, javed.absar, eraman, kcc, bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D60831

llvm-svn: 363046

1 files changed, 26 insertions, 26 deletions

diff --git a/llvm/test/Transforms/LoopIdiom/bcmp-debugify-remarks.ll b/llvm/test/Transforms/LoopIdiom/bcmp-debugify-remarks.ll
index b3bab51b7ee..f21def9ec0c 100644
--- a/llvm/test/Transforms/LoopIdiom/bcmp-debugify-remarks.ll
+++ b/llvm/test/Transforms/LoopIdiom/bcmp-debugify-remarks.ll
@@ -40,19 +40,19 @@ define i1 @_Z43index_iteration_eq_variable_size_no_overlapPKcm(i8* nocapture %pt
 ; CHECK:       for.body:
 ; CHECK-NEXT:    [[I_015:%.*]] = phi i64 [ [[INC]], [[FOR_COND:%.*]] ], [ 0, [[FOR_BODY_PREHEADER]] ], !dbg !28
 ; CHECK-NEXT:    call void @llvm.dbg.value(metadata i64 [[I_015]], metadata !14, metadata !DIExpression()), !dbg !28
-; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, i8* [[PTR]], i64 [[I_015]], !dbg !25
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8* [[ARRAYIDX]], metadata !15, metadata !DIExpression()), !dbg !25
-; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[ARRAYIDX]], !dbg !29
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8 [[V0]], metadata !16, metadata !DIExpression()), !dbg !29
-; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, i8* [[ADD_PTR]], i64 [[I_015]], !dbg !30
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8* [[ARRAYIDX1]], metadata !17, metadata !DIExpression()), !dbg !30
-; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[ARRAYIDX1]], !dbg !31
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8 [[V1]], metadata !18, metadata !DIExpression()), !dbg !31
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[V0]], [[V1]], !dbg !32
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i1 [[CMP3]], metadata !19, metadata !DIExpression()), !dbg !32
-; CHECK-NEXT:    [[INC]] = add nuw i64 [[I_015]], 1, !dbg !33
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i64 [[INC]], metadata !20, metadata !DIExpression()), !dbg !33
-; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_COND]], label [[CLEANUP_LOOPEXIT]], !dbg !34
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, i8* [[PTR]], i64 [[I_015]], !dbg !29
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8* [[ARRAYIDX]], metadata !15, metadata !DIExpression()), !dbg !29
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[ARRAYIDX]], !dbg !30
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8 [[V0]], metadata !16, metadata !DIExpression()), !dbg !30
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, i8* [[ADD_PTR]], i64 [[I_015]], !dbg !31
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8* [[ARRAYIDX1]], metadata !17, metadata !DIExpression()), !dbg !31
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[ARRAYIDX1]], !dbg !32
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8 [[V1]], metadata !18, metadata !DIExpression()), !dbg !32
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[V0]], [[V1]], !dbg !33
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i1 [[CMP3]], metadata !19, metadata !DIExpression()), !dbg !33
+; CHECK-NEXT:    [[INC]] = add nuw i64 [[I_015]], 1, !dbg !34
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i64 [[INC]], metadata !20, metadata !DIExpression()), !dbg !34
+; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_COND]], label [[CLEANUP_LOOPEXIT]], !dbg !25
 ; CHECK:       cleanup.loopexit:
 ; CHECK-NEXT:    [[RES_PH:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_COND]] ]
 ; CHECK-NEXT:    br label [[CLEANUP]], !dbg !35
@@ -100,19 +100,19 @@ define void @_Z16loop_within_loopmPPKcS1_Pm(i64 %outer_count, i8** %ptr0, i8** %
 ; CHECK:       for.body:
 ; CHECK-NEXT:    [[I_012:%.*]] = phi i64 [ [[INC:%.*]], [[_ZNST3__15EQUALIPKCS2_EEBT_S3_T0__EXIT:%.*]] ], [ 0, [[FOR_BODY_PREHEADER]] ], !dbg !64
 ; CHECK-NEXT:    call void @llvm.dbg.value(metadata i64 [[I_012]], metadata !40, metadata !DIExpression()), !dbg !64
-; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8*, i8** [[PTR0:%.*]], i64 [[I_012]], !dbg !62
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8** [[ARRAYIDX]], metadata !41, metadata !DIExpression()), !dbg !62
-; CHECK-NEXT:    [[T0:%.*]] = load i8*, i8** [[ARRAYIDX]], !dbg !65
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8* [[T0]], metadata !42, metadata !DIExpression()), !dbg !65
-; CHECK-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i64, i64* [[COUNT:%.*]], i64 [[I_012]], !dbg !66
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i64* [[ARRAYIDX2]], metadata !43, metadata !DIExpression()), !dbg !66
-; CHECK-NEXT:    [[T1:%.*]] = load i64, i64* [[ARRAYIDX2]], !dbg !67
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i64 [[T1]], metadata !44, metadata !DIExpression()), !dbg !67
-; CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, i8* [[T0]], i64 [[T1]], !dbg !68
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8* [[ADD_PTR]], metadata !45, metadata !DIExpression()), !dbg !68
-; CHECK-NEXT:    [[CMP5_I_I:%.*]] = icmp eq i64 [[T1]], 0, !dbg !69
-; CHECK-NEXT:    call void @llvm.dbg.value(metadata i1 [[CMP5_I_I]], metadata !46, metadata !DIExpression()), !dbg !69
-; CHECK-NEXT:    br i1 [[CMP5_I_I]], label [[_ZNST3__15EQUALIPKCS2_EEBT_S3_T0__EXIT]], label [[FOR_BODY_I_I_PREHEADER:%.*]], !dbg !70
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8*, i8** [[PTR0:%.*]], i64 [[I_012]], !dbg !65
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8** [[ARRAYIDX]], metadata !41, metadata !DIExpression()), !dbg !65
+; CHECK-NEXT:    [[T0:%.*]] = load i8*, i8** [[ARRAYIDX]], !dbg !66
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8* [[T0]], metadata !42, metadata !DIExpression()), !dbg !66
+; CHECK-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i64, i64* [[COUNT:%.*]], i64 [[I_012]], !dbg !67
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i64* [[ARRAYIDX2]], metadata !43, metadata !DIExpression()), !dbg !67
+; CHECK-NEXT:    [[T1:%.*]] = load i64, i64* [[ARRAYIDX2]], !dbg !68
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i64 [[T1]], metadata !44, metadata !DIExpression()), !dbg !68
+; CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, i8* [[T0]], i64 [[T1]], !dbg !69
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8* [[ADD_PTR]], metadata !45, metadata !DIExpression()), !dbg !69
+; CHECK-NEXT:    [[CMP5_I_I:%.*]] = icmp eq i64 [[T1]], 0, !dbg !70
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata i1 [[CMP5_I_I]], metadata !46, metadata !DIExpression()), !dbg !70
+; CHECK-NEXT:    br i1 [[CMP5_I_I]], label [[_ZNST3__15EQUALIPKCS2_EEBT_S3_T0__EXIT]], label [[FOR_BODY_I_I_PREHEADER:%.*]], !dbg !62
 ; CHECK:       for.body.i.i.preheader:
 ; CHECK-NEXT:    [[ARRAYIDX3:%.*]] = getelementptr inbounds i8*, i8** [[PTR1:%.*]], i64 [[I_012]], !dbg !71
 ; CHECK-NEXT:    call void @llvm.dbg.value(metadata i8** [[ARRAYIDX3]], metadata !47, metadata !DIExpression()), !dbg !71