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llvm-project/llvm/test/CodeGen/X86/fastisel-memset-flush.ll

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[FastISel][test] %llc_dwarf -mtriple -> llc -mtriple if config.target_triple contains 'windows-msvc', %llc_dwarf has a -mtriple: llc.exe: for the --mtriple option: may only occur zero or one times!
2020-11-10 04:10:44 +08:00
; RUN: llc -mtriple=x86_64 -O0 < %s | FileCheck %s
[FastISel] Reduce spills around mem-intrinsic calls FastISel generates instructions to materialize "local values" at the top of a block, in the hope that these values could be reused within the block. To reduce spills and restores, FastISel treats calls as sub-block boundaries, flushing the "local value map" at each call. This patch treats the mem* intrinsics as if they were calls, because at O0 generally they are calls. Eliminating these spills/restores is actually better for debugging (especially a "continue at this line" command), code size, stack frame size, and maybe even performance. Differential Revision: https://reviews.llvm.org/D90877
2020-11-06 05:09:10 +08:00
define dso_local void @foo() !dbg !7 {
entry:
%a = alloca i32, align 4
store i32 0, i32* %a, align 4, !dbg !9
%0 = bitcast i32* %a to i8*, !dbg !10
call void @llvm.memset.p0i8.i64(i8* align 4 %0, i8 -86, i64 4, i1 false), !dbg !10
%1 = bitcast i32* %a to i8*, !dbg !11
call void @other(i8* %1), !dbg !12
ret void, !dbg !13
}
; CHECK: callq memset
; CHECK-NEXT: .loc 1 9 9
; CHECK-NEXT: leaq
; CHECK-NEXT: .loc 1 9 3
; CHECK-NEXT: callq other
declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg)
declare dso_local void @other(i8*)
!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 12.0.0 (https://github.com/llvm/llvm-project eaae6fdf67e1f61599331d69a41a7dafe6199667)", isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2, splitDebugInlining: false, nameTableKind: None)
!1 = !DIFile(filename: "memset-test.c", directory: "/home/probinson/projects/scratch")
!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 12.0.0 (https://github.com/llvm/llvm-project eaae6fdf67e1f61599331d69a41a7dafe6199667)"}
!7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 4, type: !8, scopeLine: 5, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
!8 = !DISubroutineType(types: !2)
!9 = !DILocation(line: 6, column: 7, scope: !7)
!10 = !DILocation(line: 8, column: 3, scope: !7)
!11 = !DILocation(line: 9, column: 9, scope: !7)
!12 = !DILocation(line: 9, column: 3, scope: !7)
!13 = !DILocation(line: 10, column: 1, scope: !7)