[llvm] 3d1aecb - [CSSPGO] Fix missing debug info of dangling pseudo probe
via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 23 14:29:02 PDT 2021
Author: wlei
Date: 2021-04-23T14:26:47-07:00
New Revision: 3d1aecbd285709f58168b3ad65c06da4b42132a9
URL: https://github.com/llvm/llvm-project/commit/3d1aecbd285709f58168b3ad65c06da4b42132a9
DIFF: https://github.com/llvm/llvm-project/commit/3d1aecbd285709f58168b3ad65c06da4b42132a9.diff
LOG: [CSSPGO] Fix missing debug info of dangling pseudo probe
While doing speculative execution opt, it conservatively drops all insn's debug info in the merged `ThenBB`(see the loop at line 2384) including the dangling probe. The missing debug info of the dangling probe will cause the wrong inference computation.
So we should avoid dropping the debug info from pseudo probe, this change try to fix this by moving the to-be dangling probe to the merging target BB before the debug info is dropped.
Reviewed By: hoy, wenlei
Differential Revision: https://reviews.llvm.org/D101195
Added:
llvm/test/Transforms/SampleProfile/pseudo-probe-dangle2.ll
Modified:
llvm/lib/Transforms/Utils/SimplifyCFG.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 3a2da84e0338..16e69c0b0d0e 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -2371,22 +2371,24 @@ bool SimplifyCFGOpt::SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB,
SpeculatedStore->getDebugLoc());
}
+ // A hoisted conditional probe should be treated as dangling so that it will
+ // not be over-counted when the samples collected on the non-conditional path
+ // are counted towards the conditional path. We leave it for the counts
+ // inference algorithm to figure out a proper count for a danglng probe.
+ moveAndDanglePseudoProbes(ThenBB, BI);
+
// Metadata can be dependent on the condition we are hoisting above.
// Conservatively strip all metadata on the instruction. Drop the debug loc
// to avoid making it appear as if the condition is a constant, which would
// be misleading while debugging.
for (auto &I : *ThenBB) {
+ assert(!isa<PseudoProbeInst>(I) &&
+ "Should not drop debug info from any pseudo probes.");
if (!SpeculatedStoreValue || &I != SpeculatedStore)
I.setDebugLoc(DebugLoc());
I.dropUnknownNonDebugMetadata();
}
- // A hoisted conditional probe should be treated as dangling so that it will
- // not be over-counted when the samples collected on the non-conditional path
- // are counted towards the conditional path. We leave it for the counts
- // inference algorithm to figure out a proper count for a danglng probe.
- moveAndDanglePseudoProbes(ThenBB, BI);
-
// Hoist the instructions.
BB->getInstList().splice(BI->getIterator(), ThenBB->getInstList(),
ThenBB->begin(), std::prev(ThenBB->end()));
diff --git a/llvm/test/Transforms/SampleProfile/pseudo-probe-dangle2.ll b/llvm/test/Transforms/SampleProfile/pseudo-probe-dangle2.ll
new file mode 100644
index 000000000000..4df2f4a6a5ff
--- /dev/null
+++ b/llvm/test/Transforms/SampleProfile/pseudo-probe-dangle2.ll
@@ -0,0 +1,186 @@
+; REQUIRES: x86_64-linux
+; RUN: opt < %s -simplifycfg -S -o %t
+; RUN: FileCheck %s < %t
+
+; Test to make sure the dangling probe's metadata not being dropped.
+; CHECK: define dso_local i32 @foo
+; CHECK: call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 5, i32 2, i64 -1), !dbg ![[#]]
+
+; Function Attrs: nounwind uwtable
+define dso_local i32 @foo(i32* nocapture %marker, i32* nocapture %move_ordering, i32* nocapture %moves, i32 %num_moves) local_unnamed_addr #0 !dbg !10 {
+entry:
+ call void @llvm.dbg.value(metadata i32* %marker, metadata !19, metadata !DIExpression()), !dbg !28
+ call void @llvm.dbg.value(metadata i32* %move_ordering, metadata !20, metadata !DIExpression()), !dbg !28
+ call void @llvm.dbg.value(metadata i32* %moves, metadata !21, metadata !DIExpression()), !dbg !28
+ call void @llvm.dbg.value(metadata i32 %num_moves, metadata !22, metadata !DIExpression()), !dbg !28
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 1, i32 0, i64 -1), !dbg !29
+ call void @llvm.dbg.value(metadata i32 -1000000, metadata !25, metadata !DIExpression()), !dbg !28
+ %0 = load i32, i32* %marker, align 4, !dbg !30, !tbaa !31
+ %inc = add nsw i32 %0, 1, !dbg !30
+ store i32 %inc, i32* %marker, align 4, !dbg !30, !tbaa !31
+ call void @llvm.dbg.value(metadata i32 %inc, metadata !27, metadata !DIExpression()), !dbg !28
+ %cmp = icmp slt i32 %0, 9, !dbg !35
+ br i1 %cmp, label %for.cond, label %if.else, !dbg !37
+
+for.cond: ; preds = %entry, %for.inc
+ %i.0 = phi i32 [ %inc6, %for.inc ], [ %inc, %entry ], !dbg !38
+ %best.0 = phi i32 [ %best.1, %for.inc ], [ -1000000, %entry ], !dbg !28
+ %tmp.0 = phi i32 [ %tmp.1, %for.inc ], [ undef, %entry ]
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 2, i32 2, i64 -1), !dbg !41
+ call void @llvm.dbg.value(metadata i32 %tmp.0, metadata !26, metadata !DIExpression()), !dbg !28
+ call void @llvm.dbg.value(metadata i32 %best.0, metadata !25, metadata !DIExpression()), !dbg !28
+ call void @llvm.dbg.value(metadata i32 %i.0, metadata !24, metadata !DIExpression()), !dbg !28
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 3, i32 0, i64 -1), !dbg !42
+ %cmp1 = icmp slt i32 %i.0, %num_moves, !dbg !44
+ br i1 %cmp1, label %for.body, label %if.end12, !dbg !45
+
+for.body: ; preds = %for.cond
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 4, i32 0, i64 -1), !dbg !46
+ %idxprom = sext i32 %i.0 to i64, !dbg !46
+ %arrayidx = getelementptr inbounds i32, i32* %move_ordering, i64 %idxprom, !dbg !46
+ %1 = load i32, i32* %arrayidx, align 4, !dbg !46, !tbaa !31
+ %cmp2 = icmp sgt i32 %1, %best.0, !dbg !49
+ br i1 %cmp2, label %if.then3, label %for.inc, !dbg !50
+
+if.then3: ; preds = %for.body
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 5, i32 0, i64 -1), !dbg !51
+ call void @llvm.dbg.value(metadata i32 %1, metadata !25, metadata !DIExpression()), !dbg !28
+ call void @llvm.dbg.value(metadata i32 %i.0, metadata !26, metadata !DIExpression()), !dbg !28
+ br label %for.inc, !dbg !53
+
+for.inc: ; preds = %for.body, %if.then3
+ %best.1 = phi i32 [ %1, %if.then3 ], [ %best.0, %for.body ], !dbg !28
+ %tmp.1 = phi i32 [ %i.0, %if.then3 ], [ %tmp.0, %for.body ]
+ call void @llvm.dbg.value(metadata i32 %tmp.1, metadata !26, metadata !DIExpression()), !dbg !28
+ call void @llvm.dbg.value(metadata i32 %best.1, metadata !25, metadata !DIExpression()), !dbg !28
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 6, i32 0, i64 -1), !dbg !54
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 7, i32 0, i64 -1), !dbg !55
+ %inc6 = add nsw i32 %i.0, 1, !dbg !55
+ call void @llvm.dbg.value(metadata i32 %inc6, metadata !24, metadata !DIExpression()), !dbg !28
+ br label %for.cond, !dbg !56, !llvm.loop !57
+
+if.else: ; preds = %entry
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 9, i32 0, i64 -1), !dbg !59
+ %cmp7 = icmp slt i32 %inc, %num_moves, !dbg !61
+ br i1 %cmp7, label %cleanup, label %if.end12, !dbg !62
+
+if.end12: ; preds = %if.else, %for.cond
+ %best.2 = phi i32 [ %best.0, %for.cond ], [ -1000000, %if.else ], !dbg !63
+ %tmp.2 = phi i32 [ %tmp.0, %for.cond ], [ undef, %if.else ]
+ call void @llvm.dbg.value(metadata i32 %tmp.2, metadata !26, metadata !DIExpression()), !dbg !28
+ call void @llvm.dbg.value(metadata i32 %best.2, metadata !25, metadata !DIExpression()), !dbg !28
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 11, i32 2, i64 -1), !dbg !28
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 8, i32 2, i64 -1), !dbg !64
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 12, i32 0, i64 -1), !dbg !65
+ %cmp13 = icmp sgt i32 %best.2, -1000000, !dbg !67
+ br i1 %cmp13, label %if.then14, label %cleanup, !dbg !68
+
+if.then14: ; preds = %if.end12
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 13, i32 0, i64 -1), !dbg !69
+ br label %cleanup, !dbg !78
+
+cleanup: ; preds = %if.end12, %if.else, %if.then14
+ %retval.0 = phi i32 [ 1, %if.then14 ], [ 1, %if.else ], [ 0, %if.end12 ], !dbg !28
+ call void @llvm.pseudoprobe(i64 -4224472938262609671, i64 14, i32 2, i64 -1), !dbg !79
+ ret i32 %retval.0, !dbg !83
+}
+
+; Function Attrs: inaccessiblememonly nounwind willreturn mustprogress
+declare void @llvm.pseudoprobe(i64, i64, i32, i64) #1
+
+; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
+declare void @llvm.dbg.value(metadata, metadata, metadata) #2
+
+attributes #0 = { nounwind uwtable "disable-tail-calls"="true" "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #1 = { inaccessiblememonly nounwind willreturn mustprogress }
+attributes #2 = { nofree nosync nounwind readnone speculatable willreturn }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6, !7}
+!llvm.ident = !{!8}
+!llvm.pseudo_probe_desc = !{!9}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 13.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "test.cpp", directory: "")
+!2 = !{}
+!3 = !{i32 7, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{i32 1, !"ThinLTO", i32 0}
+!7 = !{i32 1, !"EnableSplitLTOUnit", i32 1}
+!8 = !{!"clang version 13.0.0"}
+!9 = !{i64 -4224472938262609671, i64 328037311046, !"foo", null}
+!10 = distinct !DISubprogram(name: "remove_one_fast", linkageName: "foo", scope: !1, file: !1, line: 8, type: !11, scopeLine: 9, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !18)
+!11 = !DISubroutineType(types: !12)
+!12 = !{!13, !14, !14, !15, !17}
+!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!14 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !13, size: 64)
+!15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !16, size: 64)
+!16 = !DIDerivedType(tag: DW_TAG_typedef, name: "move_s", file: !1, line: 6, baseType: !13)
+!17 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !13)
+!18 = !{!19, !20, !21, !22, !23, !24, !25, !26, !27}
+!19 = !DILocalVariable(name: "marker", arg: 1, scope: !10, file: !1, line: 8, type: !14)
+!20 = !DILocalVariable(name: "move_ordering", arg: 2, scope: !10, file: !1, line: 8, type: !14)
+!21 = !DILocalVariable(name: "moves", arg: 3, scope: !10, file: !1, line: 9, type: !15)
+!22 = !DILocalVariable(name: "num_moves", arg: 4, scope: !10, file: !1, line: 9, type: !17)
+!23 = !DILocalVariable(name: "tmpmv", scope: !10, file: !1, line: 10, type: !16)
+!24 = !DILocalVariable(name: "i", scope: !10, file: !1, line: 11, type: !13)
+!25 = !DILocalVariable(name: "best", scope: !10, file: !1, line: 11, type: !13)
+!26 = !DILocalVariable(name: "tmp", scope: !10, file: !1, line: 12, type: !13)
+!27 = !DILocalVariable(name: "mark", scope: !10, file: !1, line: 12, type: !13)
+!28 = !DILocation(line: 0, scope: !10)
+!29 = !DILocation(line: 10, column: 5, scope: !10)
+!30 = !DILocation(line: 14, column: 14, scope: !10)
+!31 = !{!32, !32, i64 0}
+!32 = !{!"int", !33, i64 0}
+!33 = !{!"omnipotent char", !34, i64 0}
+!34 = !{!"Simple C++ TBAA"}
+!35 = !DILocation(line: 17, column: 14, scope: !36)
+!36 = distinct !DILexicalBlock(scope: !10, file: !1, line: 17, column: 9)
+!37 = !DILocation(line: 17, column: 9, scope: !10)
+!38 = !DILocation(line: 0, scope: !39)
+!39 = distinct !DILexicalBlock(scope: !40, file: !1, line: 18, column: 9)
+!40 = distinct !DILexicalBlock(scope: !36, file: !1, line: 17, column: 20)
+!41 = !DILocation(line: 18, column: 18, scope: !39)
+!42 = !DILocation(line: 18, column: 24, scope: !43)
+!43 = distinct !DILexicalBlock(scope: !39, file: !1, line: 18, column: 9)
+!44 = !DILocation(line: 18, column: 26, scope: !43)
+!45 = !DILocation(line: 18, column: 9, scope: !39)
+!46 = !DILocation(line: 19, column: 17, scope: !47)
+!47 = distinct !DILexicalBlock(scope: !48, file: !1, line: 19, column: 17)
+!48 = distinct !DILexicalBlock(scope: !43, file: !1, line: 18, column: 44)
+!49 = !DILocation(line: 19, column: 34, scope: !47)
+!50 = !DILocation(line: 19, column: 17, scope: !48)
+!51 = !DILocation(line: 20, column: 24, scope: !52)
+!52 = distinct !DILexicalBlock(scope: !47, file: !1, line: 19, column: 42)
+!53 = !DILocation(line: 22, column: 13, scope: !52)
+!54 = !DILocation(line: 23, column: 9, scope: !48)
+!55 = !DILocation(line: 18, column: 40, scope: !43)
+!56 = !DILocation(line: 18, column: 9, scope: !43)
+!57 = distinct !{!57, !45, !58}
+!58 = !DILocation(line: 23, column: 9, scope: !39)
+!59 = !DILocation(line: 24, column: 16, scope: !60)
+!60 = distinct !DILexicalBlock(scope: !36, file: !1, line: 24, column: 16)
+!61 = !DILocation(line: 24, column: 21, scope: !60)
+!62 = !DILocation(line: 24, column: 16, scope: !36)
+!63 = !DILocation(line: 11, column: 12, scope: !10)
+!64 = !DILocation(line: 24, column: 5, scope: !40)
+!65 = !DILocation(line: 31, column: 9, scope: !66)
+!66 = distinct !DILexicalBlock(scope: !10, file: !1, line: 31, column: 9)
+!67 = !DILocation(line: 31, column: 14, scope: !66)
+!68 = !DILocation(line: 31, column: 9, scope: !10)
+!69 = !DILocation(line: 35, column: 30, scope: !70)
+!70 = distinct !DILexicalBlock(scope: !66, file: !1, line: 31, column: 22)
+!71 = !DILocation(line: 35, column: 9, scope: !70)
+!72 = !DILocation(line: 35, column: 28, scope: !70)
+!73 = !DILocation(line: 36, column: 29, scope: !70)
+!74 = !DILocation(line: 38, column: 17, scope: !70)
+!75 = !DILocation(line: 39, column: 23, scope: !70)
+!76 = !DILocation(line: 39, column: 21, scope: !70)
+!77 = !DILocation(line: 40, column: 20, scope: !70)
+!78 = !DILocation(line: 42, column: 9, scope: !70)
+!79 = !DILocation(line: 44, column: 9, scope: !80)
+!80 = distinct !DILexicalBlock(scope: !66, file: !1, line: 43, column: 12)
+!81 = !DILocation(line: 25, column: 16, scope: !82)
+!82 = distinct !DILexicalBlock(scope: !60, file: !1, line: 24, column: 34)
+!83 = !DILocation(line: 46, column: 1, scope: !10)
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