llvm-mirror/test/Transforms/InstSimplify/assume.ll
Shiva Chen a2029fa58e [DebugInfo] Add DILabel metadata and intrinsic llvm.dbg.label.
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is

!DILabel(scope: !1, name: "foo", file: !2, line: 3)

We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is

llvm.dbg.label(metadata !1)

It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.

We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.

Differential Revision: https://reviews.llvm.org/D45024

Patch by Hsiangkai Wang.

llvm-svn: 331841
2018-05-09 02:40:45 +00:00

94 lines
3.5 KiB
LLVM

; NOTE: Assertions have been autogenerated by update_test_checks.py
; RUN: opt -instsimplify -S < %s 2>&1 -pass-remarks-analysis=.* | FileCheck %s
; Verify that warnings are emitted for the 2nd and 3rd tests.
; CHECK: remark: /tmp/s.c:1:13: Detected conflicting code assumptions.
; CHECK: remark: /tmp/s.c:4:10: Detected conflicting code assumptions.
; CHECK: remark: /tmp/s.c:5:50: Detected conflicting code assumptions.
define void @test1() {
; CHECK-LABEL: @test1(
; CHECK: ret void
;
call void @llvm.assume(i1 1)
ret void
}
; The alloca guarantees that the low bits of %a are zero because of alignment.
; The assume says the opposite. The assume is processed last, so that's the
; return value. There's no way to win (we can't undo transforms that happened
; based on half-truths), so just don't crash.
define i64 @PR31809() !dbg !7 {
; CHECK-LABEL: @PR31809(
; CHECK-NEXT: ret i64 3
;
%a = alloca i32
%t1 = ptrtoint i32* %a to i64, !dbg !9
%cond = icmp eq i64 %t1, 3
call void @llvm.assume(i1 %cond)
ret i64 %t1
}
; Similar to above: there's no way to know which assumption is truthful,
; so just don't crash. The second icmp+assume gets processed later, so that
; determines the return value.
define i8 @conflicting_assumptions(i8 %x) !dbg !10 {
; CHECK-LABEL: @conflicting_assumptions(
; CHECK-NEXT: call void @llvm.assume(i1 false)
; CHECK-NEXT: [[COND2:%.*]] = icmp eq i8 %x, 4
; CHECK-NEXT: call void @llvm.assume(i1 [[COND2]])
; CHECK-NEXT: ret i8 5
;
%add = add i8 %x, 1, !dbg !11
%cond1 = icmp eq i8 %x, 3
call void @llvm.assume(i1 %cond1)
%cond2 = icmp eq i8 %x, 4
call void @llvm.assume(i1 %cond2)
ret i8 %add
}
; Another case of conflicting assumptions. This would crash because we'd
; try to set more known bits than existed in the known bits struct.
define void @PR36270(i32 %b) !dbg !13 {
; CHECK-LABEL: @PR36270(
; CHECK-NEXT: tail call void @llvm.assume(i1 false)
; CHECK-NEXT: unreachable
;
%B7 = xor i32 -1, 2147483647
%and1 = and i32 %b, 3
%B12 = lshr i32 %B7, %and1, !dbg !14
%C1 = icmp ult i32 %and1, %B12
tail call void @llvm.assume(i1 %C1)
%cmp2 = icmp eq i32 0, %B12
tail call void @llvm.assume(i1 %cmp2)
unreachable
}
declare void @llvm.assume(i1) nounwind
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4, !5}
!llvm.ident = !{!6}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 4.0.0 (trunk 282540) (llvm/trunk 282542)", isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2)
!1 = !DIFile(filename: "/tmp/s.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 4.0.0 (trunk 282540) (llvm/trunk 282542)"}
!7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !0, retainedNodes: !2)
!8 = !DISubroutineType(types: !2)
!9 = !DILocation(line: 1, column: 13, scope: !7)
!10 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 3, type: !8, isLocal: false, isDefinition: true, scopeLine: 3, isOptimized: true, unit: !0, retainedNodes: !2)
!11 = !DILocation(line: 4, column: 10, scope: !10)
!12 = !DILocation(line: 4, column: 3, scope: !10)
!13 = distinct !DISubprogram(name: "PR36270", scope: !1, file: !1, line: 3, type: !8, isLocal: false, isDefinition: true, scopeLine: 3, isOptimized: true, unit: !0, retainedNodes: !2)
!14 = !DILocation(line: 5, column: 50, scope: !13)