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llvm-project/llvm/test/Transforms/InstCombine/lifetime.ll

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[InstCombine] Remove trivially empty lifetime start/end ranges. Summary: Some passes may open up opportunities for optimizations, leaving empty lifetime start/end ranges. For example, with the following code: void foo(char *, char *); void bar(int Size, bool flag) { for (int i = 0; i < Size; ++i) { char text[1]; char buff[1]; if (flag) foo(text, buff); // BBFoo } } the loop unswitch pass will create 2 versions of the loop, one with flag==true, and the other one with flag==false, but always leaving the BBFoo basic block, with lifetime ranges covering the scope of the for loop. Simplify CFG will then remove BBFoo in the case where flag==false, but will leave the lifetime markers. This patch teaches InstCombine to remove trivially empty lifetime marker ranges, that is ranges ending right after they were started (ignoring debug info or other lifetime markers in the range). This fixes PR24598: excessive compile time after r234581. Reviewers: reames, chandlerc Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D13305 llvm-svn: 249018
2015-10-01 22:54:31 +08:00
; RUN: opt < %s -instcombine -S | FileCheck %s
declare void @llvm.dbg.declare(metadata, metadata, metadata)
declare void @llvm.lifetime.start(i64, i8* nocapture)
declare void @llvm.lifetime.end(i64, i8* nocapture)
declare void @foo(i8* nocapture, i8* nocapture)
DI: Reverse direction of subprogram -> function edge. Previously, subprograms contained a metadata reference to the function they described. Because most clients need to get or set a subprogram for a given function rather than the other way around, this created unneeded inefficiency. For example, many passes needed to call the function llvm::makeSubprogramMap() to build a mapping from functions to subprograms, and the IR linker needed to fix up function references in a way that caused quadratic complexity in the IR linking phase of LTO. This change reverses the direction of the edge by storing the subprogram as function-level metadata and removing DISubprogram's function field. Since this is an IR change, a bitcode upgrade has been provided. Fixes PR23367. An upgrade script for textual IR for out-of-tree clients is attached to the PR. Differential Revision: http://reviews.llvm.org/D14265 llvm-svn: 252219
2015-11-06 06:03:56 +08:00
define void @bar(i1 %flag) !dbg !4 {
[InstCombine] Remove trivially empty lifetime start/end ranges. Summary: Some passes may open up opportunities for optimizations, leaving empty lifetime start/end ranges. For example, with the following code: void foo(char *, char *); void bar(int Size, bool flag) { for (int i = 0; i < Size; ++i) { char text[1]; char buff[1]; if (flag) foo(text, buff); // BBFoo } } the loop unswitch pass will create 2 versions of the loop, one with flag==true, and the other one with flag==false, but always leaving the BBFoo basic block, with lifetime ranges covering the scope of the for loop. Simplify CFG will then remove BBFoo in the case where flag==false, but will leave the lifetime markers. This patch teaches InstCombine to remove trivially empty lifetime marker ranges, that is ranges ending right after they were started (ignoring debug info or other lifetime markers in the range). This fixes PR24598: excessive compile time after r234581. Reviewers: reames, chandlerc Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D13305 llvm-svn: 249018
2015-10-01 22:54:31 +08:00
entry:
; CHECK-LABEL: @bar(
; CHECK: %[[T:[^ ]+]] = getelementptr inbounds [1 x i8], [1 x i8]* %text
; CHECK: %[[B:[^ ]+]] = getelementptr inbounds [1 x i8], [1 x i8]* %buff
; CHECK: if:
; CHECK-NEXT: br label %bb2
; CHECK: bb2:
; CHECK-NEXT: br label %bb3
; CHECK: bb3:
; CHECK-NEXT: call void @llvm.dbg.declare
; CHECK-NEXT: br label %fin
; CHECK: call void @llvm.lifetime.start(i64 1, i8* %[[T]])
; CHECK-NEXT: call void @llvm.lifetime.start(i64 1, i8* %[[B]])
; CHECK-NEXT: call void @foo(i8* %[[B]], i8* %[[T]])
; CHECK-NEXT: call void @llvm.lifetime.end(i64 1, i8* %[[B]])
; CHECK-NEXT: call void @llvm.lifetime.end(i64 1, i8* %[[T]])
%text = alloca [1 x i8], align 1
%buff = alloca [1 x i8], align 1
%0 = getelementptr inbounds [1 x i8], [1 x i8]* %text, i64 0, i64 0
%1 = getelementptr inbounds [1 x i8], [1 x i8]* %buff, i64 0, i64 0
br i1 %flag, label %if, label %else
if:
call void @llvm.lifetime.start(i64 1, i8* %0)
call void @llvm.lifetime.start(i64 1, i8* %1)
call void @llvm.lifetime.end(i64 1, i8* %1)
call void @llvm.lifetime.end(i64 1, i8* %0)
br label %bb2
bb2:
call void @llvm.lifetime.start(i64 1, i8* %0)
call void @llvm.lifetime.start(i64 1, i8* %1)
call void @llvm.lifetime.end(i64 1, i8* %0)
call void @llvm.lifetime.end(i64 1, i8* %1)
br label %bb3
bb3:
call void @llvm.lifetime.start(i64 1, i8* %0)
call void @llvm.dbg.declare(metadata [1 x i8]* %text, metadata !14, metadata !25), !dbg !26
call void @llvm.lifetime.end(i64 1, i8* %0)
br label %fin
else:
call void @llvm.lifetime.start(i64 1, i8* %0)
call void @llvm.lifetime.start(i64 1, i8* %1)
call void @foo(i8* %1, i8* %0)
call void @llvm.lifetime.end(i64 1, i8* %1)
call void @llvm.lifetime.end(i64 1, i8* %0)
br label %fin
fin:
ret void
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!22, !23}
!llvm.ident = !{!24}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 248826) (llvm/trunk 248827)", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3)
!1 = !DIFile(filename: "test.cpp", directory: "/home/user")
!2 = !{}
!3 = !{!4}
DI: Reverse direction of subprogram -> function edge. Previously, subprograms contained a metadata reference to the function they described. Because most clients need to get or set a subprogram for a given function rather than the other way around, this created unneeded inefficiency. For example, many passes needed to call the function llvm::makeSubprogramMap() to build a mapping from functions to subprograms, and the IR linker needed to fix up function references in a way that caused quadratic complexity in the IR linking phase of LTO. This change reverses the direction of the edge by storing the subprogram as function-level metadata and removing DISubprogram's function field. Since this is an IR change, a bitcode upgrade has been provided. Fixes PR23367. An upgrade script for textual IR for out-of-tree clients is attached to the PR. Differential Revision: http://reviews.llvm.org/D14265 llvm-svn: 252219
2015-11-06 06:03:56 +08:00
!4 = distinct !DISubprogram(name: "bar", linkageName: "bar", scope: !1, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, variables: !8)
[InstCombine] Remove trivially empty lifetime start/end ranges. Summary: Some passes may open up opportunities for optimizations, leaving empty lifetime start/end ranges. For example, with the following code: void foo(char *, char *); void bar(int Size, bool flag) { for (int i = 0; i < Size; ++i) { char text[1]; char buff[1]; if (flag) foo(text, buff); // BBFoo } } the loop unswitch pass will create 2 versions of the loop, one with flag==true, and the other one with flag==false, but always leaving the BBFoo basic block, with lifetime ranges covering the scope of the for loop. Simplify CFG will then remove BBFoo in the case where flag==false, but will leave the lifetime markers. This patch teaches InstCombine to remove trivially empty lifetime marker ranges, that is ranges ending right after they were started (ignoring debug info or other lifetime markers in the range). This fixes PR24598: excessive compile time after r234581. Reviewers: reames, chandlerc Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D13305 llvm-svn: 249018
2015-10-01 22:54:31 +08:00
!5 = !DISubroutineType(types: !6)
!6 = !{null, !7}
!7 = !DIBasicType(name: "bool", size: 8, align: 8, encoding: DW_ATE_boolean)
!8 = !{!9, !11, !12, !14, !21}
!9 = !DILocalVariable(name: "Size", arg: 1, scope: !4, file: !1, line: 2, type: !10)
!10 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!11 = !DILocalVariable(name: "flag", arg: 2, scope: !4, file: !1, line: 2, type: !7)
!12 = !DILocalVariable(name: "i", scope: !13, file: !1, line: 3, type: !10)
!13 = distinct !DILexicalBlock(scope: !4, file: !1, line: 3, column: 3)
!14 = !DILocalVariable(name: "text", scope: !15, file: !1, line: 4, type: !17)
!15 = distinct !DILexicalBlock(scope: !16, file: !1, line: 3, column: 30)
!16 = distinct !DILexicalBlock(scope: !13, file: !1, line: 3, column: 3)
!17 = !DICompositeType(tag: DW_TAG_array_type, baseType: !18, size: 8, align: 8, elements: !19)
!18 = !DIBasicType(name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
!19 = !{!20}
!20 = !DISubrange(count: 1)
!21 = !DILocalVariable(name: "buff", scope: !15, file: !1, line: 5, type: !17)
!22 = !{i32 2, !"Dwarf Version", i32 4}
!23 = !{i32 2, !"Debug Info Version", i32 3}
!24 = !{!"clang version 3.8.0 (trunk 248826) (llvm/trunk 248827)"}
!25 = !DIExpression()
!26 = !DILocation(line: 4, column: 10, scope: !15)