[llvm] r357499 - [DebugInfo] Fix pr41180 : Loop Vectorization Debugify Failure
Vedant Kumar via llvm-commits
llvm-commits at lists.llvm.org
Tue Apr 2 10:28:34 PDT 2019
Author: vedantk
Date: Tue Apr 2 10:28:34 2019
New Revision: 357499
URL: http://llvm.org/viewvc/llvm-project?rev=357499&view=rev
Log:
[DebugInfo] Fix pr41180 : Loop Vectorization Debugify Failure
Bug: https://bugs.llvm.org/show_bug.cgi?id=41180
In the bug test case the debug location was missing for the cmp instruction in
the "middle block" BB. This patch fixes the bug by copying the debug location
from the cmp of the scalar loop's terminator branch, if it exists.
The patch also fixes the debug location on the subsequent branch instruction.
It was previously using the location of the of the original loop's pre-header
block terminator. Both of these instructions will now map to the source line of
the conditional branch in the original loop.
A regression test has been added that covers these issues.
Patch by Orlando Cazalet-Hyams!
Differential Revision: https://reviews.llvm.org/D59944
Added:
llvm/trunk/test/Transforms/LoopVectorize/middle-block-dbg.ll
Modified:
llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
Modified: llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp?rev=357499&r1=357498&r2=357499&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp (original)
+++ llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp Tue Apr 2 10:28:34 2019
@@ -2864,17 +2864,35 @@ BasicBlock *InnerLoopVectorizer::createV
OrigPhi->setIncomingValue(BlockIdx, BCResumeVal);
}
+ // We need the OrigLoop (scalar loop part) latch terminator to help
+ // produce correct debug info for the middle block BB instructions.
+ // The legality check stage guarantees that the loop will have a single
+ // latch.
+ assert(isa<BranchInst>(OrigLoop->getLoopLatch()->getTerminator()) &&
+ "Scalar loop latch terminator isn't a branch");
+ BranchInst *ScalarLatchBr =
+ cast<BranchInst>(OrigLoop->getLoopLatch()->getTerminator());
+
// Add a check in the middle block to see if we have completed
// all of the iterations in the first vector loop.
// If (N - N%VF) == N, then we *don't* need to run the remainder.
// If tail is to be folded, we know we don't need to run the remainder.
Value *CmpN = Builder.getTrue();
- if (!Cost->foldTailByMasking())
+ if (!Cost->foldTailByMasking()) {
CmpN =
CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, Count,
CountRoundDown, "cmp.n", MiddleBlock->getTerminator());
- ReplaceInstWithInst(MiddleBlock->getTerminator(),
- BranchInst::Create(ExitBlock, ScalarPH, CmpN));
+
+ // Provide correct stepping behaviour by using the same DebugLoc as the
+ // scalar loop latch branch cmp if it exists.
+ if (CmpInst *ScalarLatchCmp =
+ dyn_cast_or_null<CmpInst>(ScalarLatchBr->getCondition()))
+ cast<Instruction>(CmpN)->setDebugLoc(ScalarLatchCmp->getDebugLoc());
+ }
+
+ BranchInst *BrInst = BranchInst::Create(ExitBlock, ScalarPH, CmpN);
+ BrInst->setDebugLoc(ScalarLatchBr->getDebugLoc());
+ ReplaceInstWithInst(MiddleBlock->getTerminator(), BrInst);
// Get ready to start creating new instructions into the vectorized body.
Builder.SetInsertPoint(&*VecBody->getFirstInsertionPt());
Added: llvm/trunk/test/Transforms/LoopVectorize/middle-block-dbg.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/middle-block-dbg.ll?rev=357499&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/middle-block-dbg.ll (added)
+++ llvm/trunk/test/Transforms/LoopVectorize/middle-block-dbg.ll Tue Apr 2 10:28:34 2019
@@ -0,0 +1,110 @@
+; RUN: opt -loop-vectorize -force-vector-width=2 -S < %s | FileCheck %s
+;
+; Confirm that the DebugLoc info for the instructions in the middle block of a
+; vectorized loop are correct. The Cmp and Br instructions should map to the
+; same source lines as the Cmp and Br of the scalar loop.
+
+; CHECK-LABEL: middle.block:
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq {{.*}}!dbg ![[DL:[0-9]+]]
+; CHECK-NEXT: br i1 [[CMP]]{{.*}} !dbg ![[DL]]
+; CHECK: ![[DL]] = !DILocation(line: 6,
+
+; This IR can be generated by running:
+; clang -g -O2 -emit-llvm -S -mllvm -opt-bisect-limit=68 vec.cpp -o - | opt -loop-vectorize -force-vector-width=2 -S -o vec.ll
+;
+; Where vec.cpp contains:
+;
+; extern int x;
+; extern int y;
+; void a() {
+; const int len = x;
+; int b[len];
+; for(int i = 0; i< len; ++i)
+; b[i] = x;
+;
+; y = b[x] + b[x-5];
+; }
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+
+@"?x@@3HA" = external dso_local local_unnamed_addr global i32, align 4
+@"?y@@3HA" = external dso_local local_unnamed_addr global i32, align 4
+
+define dso_local void @"?a@@YAXXZ"() local_unnamed_addr #0 !dbg !8 {
+entry:
+ %0 = load i32, i32* @"?x@@3HA", align 4, !dbg !23, !tbaa !24
+ %1 = zext i32 %0 to i64, !dbg !28
+ %vla = alloca i32, i64 %1, align 16, !dbg !28
+ %cmp10 = icmp sgt i32 %0, 0, !dbg !30
+ br i1 %cmp10, label %for.body.preheader, label %for.cond.cleanup, !dbg !30
+
+for.body.preheader:
+ br label %for.body, !dbg !31
+
+for.cond.cleanup.loopexit:
+ %idxprom1.phi.trans.insert = sext i32 %0 to i64
+ %arrayidx2.phi.trans.insert = getelementptr inbounds i32, i32* %vla, i64 %idxprom1.phi.trans.insert
+ %.pre = load i32, i32* %arrayidx2.phi.trans.insert, align 4, !dbg !33, !tbaa !24
+ br label %for.cond.cleanup, !dbg !33
+
+for.cond.cleanup:
+ %2 = phi i32 [ %.pre, %for.cond.cleanup.loopexit ], [ undef, %entry ], !dbg !33
+ %sub = add nsw i32 %0, -5, !dbg !33
+ %idxprom3 = sext i32 %sub to i64, !dbg !33
+ %arrayidx4 = getelementptr inbounds i32, i32* %vla, i64 %idxprom3, !dbg !33
+ %3 = load i32, i32* %arrayidx4, align 4, !dbg !33, !tbaa !24
+ %add = add nsw i32 %3, %2, !dbg !33
+ store i32 %add, i32* @"?y@@3HA", align 4, !dbg !33, !tbaa !24
+ ret void, !dbg !34
+
+for.body:
+ %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %for.body.preheader ]
+ %arrayidx = getelementptr inbounds i32, i32* %vla, i64 %indvars.iv, !dbg !31
+ store i32 %0, i32* %arrayidx, align 4, !dbg !31, !tbaa !24
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !35
+ %exitcond = icmp eq i64 %indvars.iv.next, %1, !dbg !30
+ br i1 %exitcond, label %for.cond.cleanup.loopexit, label %for.body, !dbg !30, !llvm.loop !36
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+!llvm.ident = !{!7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 9.0.0 (https://github.com/llvm/llvm-project.git 045b8544fd2c4e14f7e72e0df2bc681d823b0838)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "vec.cpp", directory: "C:\5CUsers\5Cgbhyamso\5Cdev\5Cllvm\5Csamples", checksumkind: CSK_MD5, checksum: "fed997f50117f5514a69caf1c2fb2c49")
+!2 = !{}
+!3 = !{i32 2, !"CodeView", i32 1}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 2}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!7 = !{!"clang version 9.0.0 (https://github.com/llvm/llvm-project.git 045b8544fd2c4e14f7e72e0df2bc681d823b0838)"}
+!8 = distinct !DISubprogram(name: "a", linkageName: "?a@@YAXXZ", scope: !1, file: !1, line: 3, type: !9, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !11)
+!9 = !DISubroutineType(types: !10)
+!10 = !{null}
+!11 = !{!12, !15, !17, !21}
+!12 = !DILocalVariable(name: "len", scope: !8, file: !1, line: 4, type: !13)
+!13 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !14)
+!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!15 = !DILocalVariable(name: "__vla_expr0", scope: !8, type: !16, flags: DIFlagArtificial)
+!16 = !DIBasicType(name: "long long unsigned int", size: 64, encoding: DW_ATE_unsigned)
+!17 = !DILocalVariable(name: "b", scope: !8, file: !1, line: 5, type: !18)
+!18 = !DICompositeType(tag: DW_TAG_array_type, baseType: !14, elements: !19)
+!19 = !{!20}
+!20 = !DISubrange(count: !15)
+!21 = !DILocalVariable(name: "i", scope: !22, file: !1, line: 6, type: !14)
+!22 = distinct !DILexicalBlock(scope: !8, file: !1, line: 6)
+!23 = !DILocation(line: 4, scope: !8)
+!24 = !{!25, !25, i64 0}
+!25 = !{!"int", !26, i64 0}
+!26 = !{!"omnipotent char", !27, i64 0}
+!27 = !{!"Simple C++ TBAA"}
+!28 = !DILocation(line: 5, scope: !8)
+!29 = !DILocation(line: 0, scope: !8)
+!30 = !DILocation(line: 6, scope: !22)
+!31 = !DILocation(line: 7, scope: !32)
+!32 = distinct !DILexicalBlock(scope: !22, file: !1, line: 6)
+!33 = !DILocation(line: 9, scope: !8)
+!34 = !DILocation(line: 10, scope: !8)
+!35 = !DILocation(line: 6, scope: !32)
+!36 = distinct !{!36, !30, !37}
+!37 = !DILocation(line: 7, scope: !22)
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