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llvm-mirror/test/CodeGen/ARM/analyze-branch-bkpt.ll
Peter Collingbourne 3f38e31261 ARM: Use BKPT instead of TRAP to implement llvm.debugtrap.
The BKPT instruction is specified to cause a software breakpoint,
and at least on Linux results in a SIGTRAP. This makes it more
suitable for implementing debugtrap than TRAP (aka UDF #254), which
is specified to cause an undefined instruction exception and results
in a SIGILL on Linux.

Moreover, BKPT is not marked as a terminator, which is not only
consistent with the IR instruction but allows the analyzeBlock
function to correctly analyze a basic block containing the instruction,
which fixes an assertion failure in the machine block placement pass
previously triggered by the included test case.

Because BKPT is only supported starting with ARMv5T, we continue to
use UDF #254 when targeting v4T.

Differential Revision: https://reviews.llvm.org/D53614

llvm-svn: 345171
2018-10-24 18:10:38 +00:00

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2.2 KiB
LLVM

; RUN: llc -o - %s -mtriple thumbv4-unknown-linux-android | FileCheck --check-prefix=V4 %s
; RUN: llc -o - %s -mtriple thumbv5-unknown-linux-android | FileCheck --check-prefix=V5 %s
; V4: udf #254
; V5: bkpt #0
define i1 @a(i32 %b) !dbg !3 {
br i1 undef, label %c, label %d, !dbg !4
d: ; preds = %0
call void @llvm.debugtrap()
br label %ah, !dbg !4
c: ; preds = %0
%aj = icmp ne i20 undef, 5
br label %ah, !dbg !4
ah: ; preds = %c, %d
%ak = phi i1 [ false, %d ], [ %aj, %c ]
call void @llvm.dbg.value(metadata i1 %ak, metadata !7, metadata !DIExpression()), !dbg !9
switch i32 %b, label %al [
i32 0, label %am
i32 10, label %an
]
an: ; preds = %ah
%ch = select i1 %ak, i32 0, i32 5
br label %am, !dbg !10
al: ; preds = %ah
br label %am, !dbg !9
am: ; preds = %al, %an, %ah
%1 = phi i32 [ 0, %al ], [ %ch, %an ], [ %b, %ah ]
unreachable
}
; Function Attrs: nounwind readnone speculatable
declare void @llvm.dbg.value(metadata, metadata, metadata) #0
; Function Attrs: nounwind
declare void @llvm.debugtrap() #1
attributes #0 = { nounwind readnone speculatable }
attributes #1 = { nounwind }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!2}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, isOptimized: false, runtimeVersion: 0, emissionKind: NoDebug)
!1 = !DIFile(filename: "a", directory: "")
!2 = !{i32 2, !"Debug Info Version", i32 3}
!3 = distinct !DISubprogram(scope: null, isLocal: false, isDefinition: true, isOptimized: false, unit: !0)
!4 = !DILocation(line: 0, scope: !5, inlinedAt: !6)
!5 = distinct !DISubprogram(scope: null, isLocal: false, isDefinition: true, isOptimized: false, unit: !0)
!6 = !DILocation(line: 0, scope: !3)
!7 = !DILocalVariable(scope: !8)
!8 = distinct !DISubprogram(scope: null, isLocal: false, isDefinition: true, isOptimized: false, unit: !0)
!9 = !DILocation(line: 0, scope: !8, inlinedAt: !6)
!10 = !DILocation(line: 0, scope: !11, inlinedAt: !6)
!11 = !DILexicalBlock(scope: !8)