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llvm-project/llvm/test/Transforms/InstCombine/debuginfo-skip.ll

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[InstCombine] Add a flag to disable LowerDbgDeclare Summary: This should improve optimized debug info for address-taken variables at the cost of inaccurate debug info in some situations. We patched this into clang and deployed this change to Chromium developers, and this significantly improved debuggability of optimized code. The long-term solution to PR34136 seems more and more like it's going to take a while, so I would like to commit this change under a flag so that it can be used as a stop-gap measure. This flag should really help so for C++ aggregates like std::string and std::vector, which are typically address-taken, even after inlining, and cannot be SROA-ed. Reviewers: aprantl, dblaikie, probinson, dberlin Subscribers: hiraditya, llvm-commits Differential Revision: https://reviews.llvm.org/D36596 llvm-svn: 313108
2017-09-13 09:43:25 +08:00
; RUN: opt -instcombine-lower-dbg-declare=0 < %s -instcombine -S | FileCheck %s
; RUN: opt -instcombine-lower-dbg-declare=1 < %s -instcombine -S | FileCheck %s
In debug builds non-trivial amount of time is spent in InstCombine processing @llvm.dbg.* calls in visitCallInst(). They can be safely ignored. llvm-svn: 303202
2017-05-17 04:08:49 +08:00
define i32 @foo(i32 %j) #0 !dbg !7 {
entry:
%j.addr = alloca i32, align 4
store i32 %j, i32* %j.addr, align 4
call void @llvm.dbg.declare(metadata i32* %j.addr, metadata !11, metadata !12), !dbg !13
Remove the obsolete offset parameter from @llvm.dbg.value There is no situation where this rarely-used argument cannot be substituted with a DIExpression and removing it allows us to simplify the DWARF backend. Note that this patch does not yet remove any of the newly dead code. rdar://problem/33580047 Differential Revision: https://reviews.llvm.org/D35951 llvm-svn: 309426
2017-07-29 04:21:02 +08:00
call void @llvm.dbg.value(metadata i32 10, metadata !16, metadata !12), !dbg !15
In debug builds non-trivial amount of time is spent in InstCombine processing @llvm.dbg.* calls in visitCallInst(). They can be safely ignored. llvm-svn: 303202
2017-05-17 04:08:49 +08:00
%0 = load i32, i32* %j.addr, align 4, !dbg !14
ret i32 %0, !dbg !15
}
[InstCombine] Add a flag to disable LowerDbgDeclare Summary: This should improve optimized debug info for address-taken variables at the cost of inaccurate debug info in some situations. We patched this into clang and deployed this change to Chromium developers, and this significantly improved debuggability of optimized code. The long-term solution to PR34136 seems more and more like it's going to take a while, so I would like to commit this change under a flag so that it can be used as a stop-gap measure. This flag should really help so for C++ aggregates like std::string and std::vector, which are typically address-taken, even after inlining, and cannot be SROA-ed. Reviewers: aprantl, dblaikie, probinson, dberlin Subscribers: hiraditya, llvm-commits Differential Revision: https://reviews.llvm.org/D36596 llvm-svn: 313108
2017-09-13 09:43:25 +08:00
; Instcombine can remove the alloca and forward the load to store, but it
; should convert the declare to dbg value.
; CHECK-LABEL: define i32 @foo(i32 %j)
; CHECK-NOT: alloca
; CHECK: call void @llvm.dbg.value(metadata i32 %j, {{.*}})
; CHECK: call void @llvm.dbg.value(metadata i32 10, {{.*}})
; CHECK: ret i32 %j
In debug builds non-trivial amount of time is spent in InstCombine processing @llvm.dbg.* calls in visitCallInst(). They can be safely ignored. llvm-svn: 303202
2017-05-17 04:08:49 +08:00
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
Remove the obsolete offset parameter from @llvm.dbg.value There is no situation where this rarely-used argument cannot be substituted with a DIExpression and removing it allows us to simplify the DWARF backend. Note that this patch does not yet remove any of the newly dead code. rdar://problem/33580047 Differential Revision: https://reviews.llvm.org/D35951 llvm-svn: 309426
2017-07-29 04:21:02 +08:00
declare void @llvm.dbg.value(metadata, metadata, metadata) #1
In debug builds non-trivial amount of time is spent in InstCombine processing @llvm.dbg.* calls in visitCallInst(). They can be safely ignored. llvm-svn: 303202
2017-05-17 04:08:49 +08:00
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4, !5}
!llvm.ident = !{!6}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang 5.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
!1 = !DIFile(filename: "a.c", directory: "/tmp")
!2 = !{}
!3 = !{i32 2, !"Dwarf Version", i32 4}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!5 = !{i32 1, !"PIC Level", i32 2}
!6 = !{!"clang version 5.0.0 (trunk 302918) (llvm/trunk 302925)"}
!7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 2, type: !8, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
!8 = !DISubroutineType(types: !9)
!9 = !{!10, !10}
!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!11 = !DILocalVariable(name: "j", arg: 1, scope: !7, file: !1, line: 2, type: !10)
!12 = !DIExpression()
!13 = !DILocation(line: 2, column: 13, scope: !7)
!14 = !DILocation(line: 5, column: 10, scope: !7)
!15 = !DILocation(line: 5, column: 3, scope: !7)
!16 = !DILocalVariable(name: "h", scope: !7, file: !1, line: 4, type: !10)