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llvm-project/llvm/test/DebugInfo/X86/sdag-ir-salvage.ll

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Rename ExpandISelPseudo->FinalizeISel, delay register reservation This allows targets to make more decisions about reserved registers after isel. For example, now it should be certain there are calls or stack objects in the frame or not, which could have been introduced by legalization. Patch by Matthias Braun llvm-svn: 363757
2019-06-19 08:25:39 +08:00
; RUN: llc -mtriple=x86_64-unknown-unknown -start-after=codegenprepare -stop-before finalize-isel %s -o - | FileCheck %s
[DebugInfo][DAG] Either salvage dangling debug info or emit Undef DBG_VALUEs In this patch SelectionDAG tries to salvage any dbg.values that are going to be dropped, in case they can be recovered from Values in the current BB. It also strengthens SelectionDAGs handling of dangling debug data, so that dbg.values are *always* emitted (as Undef or otherwise) instead of dangling forever. The motivation behind this patch exists in the new test case: a memory address (here a bitcast and GEP) exist in one basic block, and a dbg.value referring to the address is left in the 'next' block. The base pointer is live across all basic blocks. In current llvm trunk the dbg.value cannot be encoded, and it isn't even emitted as an Undef DBG_VALUE. The change is simply: if we're definitely going to drop a dbg.value, repeatedly apply salvageDebugInfo to its operand until either we find something that can be encoded, or we can't salvage any further in which case we produce an Undef DBG_VALUE. To know when we're "definitely going to drop a dbg.value", SelectionDAG signals SelectionDAGBuilder when all IR instructions have been encoded to force salvaging. This ensures that any dbg.value that's dangling after DAG creation will have a corresponding DBG_VALUE encoded. Differential Revision: https://reviews.llvm.org/D57694 llvm-svn: 353954
2019-02-14 00:33:05 +08:00
; Test that the dbg.value for %baz, which doesn't exist in the 'next' bb,
; can be salvaged back to the underlying argument vreg.
; CHECK: ![[AAAVAR:.*]] = !DILocalVariable(name: "aaa",
; CHECK-LABEL: bb.1.next:
; CHECK: DBG_VALUE %{{[0-9]+}}, $noreg, ![[AAAVAR]]
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-linux-gnu"
define i8 @f(i32* %foo) local_unnamed_addr !dbg !6 {
entry:
%bar = getelementptr i32, i32* %foo, i32 4
%baz = bitcast i32* %bar to i8*
%quux = load i8, i8* %baz
br label %next
next: ; preds = %entry
tail call void @llvm.dbg.value(metadata i8* %baz, metadata !15, metadata !DIExpression()), !dbg !30
%xyzzy = add i8 %quux, 123
br label %fin
fin: ; preds = %next
%trains = getelementptr i32, i32* %foo, i32 3
%planes = bitcast i32* %trains to i8*
%cars = load i8, i8* %planes
%ret = add i8 %xyzzy, %cars
ret i8 %ret
}
; Function Attrs: nounwind readnone speculatable
declare void @llvm.dbg.value(metadata, metadata, metadata) #0
attributes #0 = { nounwind readnone speculatable }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!25, !26, !27, !28}
!llvm.ident = !{!29}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
!1 = !DIFile(filename: "test.c", directory: ".")
!2 = !{}
!6 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 18, type: !7, scopeLine: 19, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !14)
!7 = !DISubroutineType(types: !8)
!8 = !{!13}
!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_unsigned)
!14 = !{!15}
!15 = !DILocalVariable(name: "aaa", scope: !6, file: !1, line: 18, type: !13)
!25 = !{i32 2, !"Dwarf Version", i32 4}
!26 = !{i32 2, !"Debug Info Version", i32 3}
!27 = !{i32 1, !"wchar_size", i32 4}
!28 = !{i32 7, !"PIC Level", i32 2}
!29 = !{!"clang"}
!30 = !DILocation(line: 18, column: 14, scope: !6)