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Revert "[DebugInfo] Prevent explosion of debug intrinsics during jump threading"

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This reverts commit fe6f6cd6b8.

Found test failure on several buildbots.
This commit is contained in:
stozer
2020-02-12 11:47:01 +00:00
parent 49a4d85f6d
commit 6ded69f294
2 changed files with 11 additions and 99 deletions
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32
llvm/lib/Transforms/Scalar/JumpThreading.cpp
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@@ -405,12 +405,6 @@ bool JumpThreadingPass::runImpl(Function &F, TargetLibraryInfo *TLI_,
continue;
while (ProcessBlock(&BB)) // Thread all of the branches we can over BB.
Changed = true;
// Jump threading may have introduced redundant debug values into BB
// which should be removed.
if (Changed)
RemoveRedundantDbgInstrs(&BB);
// Stop processing BB if it's the entry or is now deleted. The following
// routines attempt to eliminate BB and locating a suitable replacement
// for the entry is non-trivial.
@@ -433,21 +427,17 @@ bool JumpThreadingPass::runImpl(Function &F, TargetLibraryInfo *TLI_,
// ProcessBlock doesn't thread BBs with unconditional TIs. However, if BB
// is "almost empty", we attempt to merge BB with its sole successor.
auto *BI = dyn_cast<BranchInst>(BB.getTerminator());
if (BI && BI->isUnconditional()) {
BasicBlock *Succ = BI->getSuccessor(0);
if (
// The terminator must be the only non-phi instruction in BB.
BB.getFirstNonPHIOrDbg()->isTerminator() &&
// Don't alter Loop headers and latches to ensure another pass can
// detect and transform nested loops later.
!LoopHeaders.count(&BB) && !LoopHeaders.count(Succ) &&
TryToSimplifyUncondBranchFromEmptyBlock(&BB, DTU)) {
RemoveRedundantDbgInstrs(Succ);
// BB is valid for cleanup here because we passed in DTU. F remains
// BB's parent until a DTU->getDomTree() event.
LVI->eraseBlock(&BB);
Changed = true;
}
if (BI && BI->isUnconditional() &&
// The terminator must be the only non-phi instruction in BB.
BB.getFirstNonPHIOrDbg()->isTerminator() &&
// Don't alter Loop headers and latches to ensure another pass can
// detect and transform nested loops later.
!LoopHeaders.count(&BB) && !LoopHeaders.count(BI->getSuccessor(0)) &&
TryToSimplifyUncondBranchFromEmptyBlock(&BB, DTU)) {
// BB is valid for cleanup here because we passed in DTU. F remains
// BB's parent until a DTU->getDomTree() event.
LVI->eraseBlock(&BB);
Changed = true;
}
}
EverChanged |= Changed;

78
llvm/test/Transforms/JumpThreading/redundant-dbg-info.ll
View File

@@ -1,78 +0,0 @@
; RUN: opt -jump-threading -S < %s | FileCheck %s
define dso_local i32 @_Z3fooi(i32 %a) !dbg !7 {
entry:
call void @llvm.dbg.value(metadata i32 %a, metadata !12, metadata !DIExpression()), !dbg !13
call void @llvm.dbg.value(metadata i32 1, metadata !14, metadata !DIExpression()), !dbg !13
%tobool = icmp ne i32 %a, 0, !dbg !15
br i1 %tobool, label %if.then, label %if.end, !dbg !17
if.then: ; preds = %entry
call void @_Z4callv(), !dbg !18
call void @llvm.dbg.value(metadata i32 0, metadata !14, metadata !DIExpression()), !dbg !13
br label %if.end, !dbg !20
if.end: ; preds = %if.then, %entry
%c.0 = phi i32 [ 0, %if.then ], [ 1, %entry ], !dbg !13
call void @llvm.dbg.value(metadata i32 %c.0, metadata !14, metadata !DIExpression()), !dbg !13
%tobool1 = icmp ne i32 %c.0, 0, !dbg !21
br i1 %tobool1, label %if.else, label %if.then2, !dbg !23
; CHECK-LABEL: if.then2:
; CHECK: call void @llvm.dbg.value({{.+}}, metadata ![[B:[0-9]+]], metadata !DIExpression())
; CHECK: call void @llvm.dbg.value({{.+}}, metadata ![[B:[0-9]+]], metadata !DIExpression())
; CHECK-NOT: call void @llvm.dbg.value({{.+}}, metadata ![[B]], metadata !DIExpression())
if.then2: ; preds = %if.end
call void @llvm.dbg.value(metadata i32 4, metadata !24, metadata !DIExpression()), !dbg !13
br label %if.end3, !dbg !25
; CHECK-LABEL: if.end3:
if.else: ; preds = %if.end
call void @llvm.dbg.value(metadata i32 6, metadata !24, metadata !DIExpression()), !dbg !13
br label %if.end3
if.end3: ; preds = %if.else, %if.then2
%b.0 = phi i32 [ 6, %if.else ], [ 4, %if.then2 ], !dbg !27
call void @llvm.dbg.value(metadata i32 %b.0, metadata !24, metadata !DIExpression()), !dbg !13
ret i32 %b.0, !dbg !28
}
; Function Attrs: nounwind readnone speculatable willreturn
declare void @llvm.dbg.declare(metadata, metadata, metadata)
declare dso_local void @_Z4callv()
; Function Attrs: nounwind readnone speculatable willreturn
declare void @llvm.dbg.value(metadata, metadata, metadata)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4, !5}
!llvm.ident = !{!6}
; CHECK: ![[B]] = !DILocalVariable(name: "b"
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 10.0.0", isOptimized: false, 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 = !{!"clang version 10.0.0"}
!7 = distinct !DISubprogram(name: "foo", linkageName: "_Z3fooi", scope: !8, file: !8, line: 3, type: !9, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
!8 = !DIFile(filename: "./test.cpp", directory: "/")
!9 = !DISubroutineType(types: !10)
!10 = !{!11, !11}
!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!12 = !DILocalVariable(name: "a", arg: 1, scope: !7, file: !8, line: 3, type: !11)
!13 = !DILocation(line: 0, scope: !7)
!14 = !DILocalVariable(name: "c", scope: !7, file: !8, line: 4, type: !11)
!15 = !DILocation(line: 5, column: 7, scope: !16)
!16 = distinct !DILexicalBlock(scope: !7, file: !8, line: 5, column: 7)
!17 = !DILocation(line: 5, column: 7, scope: !7)
!18 = !DILocation(line: 6, column: 5, scope: !19)
!19 = distinct !DILexicalBlock(scope: !16, file: !8, line: 5, column: 10)
!20 = !DILocation(line: 8, column: 3, scope: !19)
!21 = !DILocation(line: 9, column: 8, scope: !22)
!22 = distinct !DILexicalBlock(scope: !7, file: !8, line: 9, column: 7)
!23 = !DILocation(line: 9, column: 7, scope: !7)
!24 = !DILocalVariable(name: "b", scope: !7, file: !8, line: 4, type: !11)
!25 = !DILocation(line: 11, column: 3, scope: !26)
!26 = distinct !DILexicalBlock(scope: !22, file: !8, line: 9, column: 11)
!27 = !DILocation(line: 0, scope: !22)
!28 = !DILocation(line: 14, column: 3, scope: !7)