| ; RUN: opt < %s -S -passes=simplifycfg | FileCheck %s |
| |
| ; Note: This patch is a complement to pr38763. |
| ; |
| ; When SimplifyCFG changes the PHI node into a select instruction, the debug |
| ; information becomes ambiguous. It causes the debugger to display unreached |
| ; lines and invalid variable values. |
| ; |
| ; When in the debugger, on the line "if (read1 > 3)", and we step from the |
| ; 'if' condition, onto the addition, then back to the 'if' again, which is |
| ; misleading because that addition doesn't really "happen" (it's speculated). |
| |
| ; IR generated with: |
| ; clang -S -g -gno-column-info -O2 -emit-llvm pr38762.cpp -o pr38762.ll -mllvm -opt-bisect-limit=10 |
| |
| ; // pr38762.cpp |
| ; int main() { |
| ; volatile int foo = 0; |
| ; int read1 = foo; |
| ; int brains = foo; |
| ; |
| ; if (read1 > 3) { |
| ; brains *= 2; |
| ; brains += 1; |
| ; } |
| ; |
| ; return brains; |
| ; } |
| |
| ; Change the debug locations associated with the PHI nodes being promoted, to |
| ; the debug locations from the insertion point in the dominant block. |
| |
| ; CHECK-LABEL: entry |
| ; CHECK: %cmp = icmp sgt i32 %foo.0., 3, !dbg !14 |
| ; CHECK: %mul = shl nsw i32 %foo.0.5, 1, !dbg !16 |
| ; CHECK-NOT: call void @llvm.dbg.value(metadata i32 %mul, metadata !15, metadata !DIExpression()), !dbg !25 |
| ; CHECK: %add = or i32 %mul, 1, !dbg !16 |
| ; CHECK-NOT: call void @llvm.dbg.value(metadata i32 %add, metadata !15, metadata !DIExpression()), !dbg !25 |
| ; CHECK: %brains.0 = select i1 %cmp, i32 %add, i32 %foo.0.5, !dbg !16 |
| |
| ; ModuleID = 'pr38762.cpp' |
| source_filename = "pr38762.cpp" |
| target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" |
| target triple = "x86_64-pc-linux-gnu" |
| |
| ; Function Attrs: norecurse nounwind uwtable |
| define dso_local i32 @main() local_unnamed_addr #0 !dbg !7 { |
| entry: |
| %foo = alloca i32, align 4 |
| store volatile i32 0, ptr %foo, align 4 |
| %foo.0. = load volatile i32, ptr %foo, align 4 |
| %foo.0.5 = load volatile i32, ptr %foo, align 4 |
| call void @llvm.dbg.value(metadata i32 %foo.0.5, metadata !15, metadata !DIExpression()), !dbg !25 |
| %cmp = icmp sgt i32 %foo.0., 3, !dbg !26 |
| br i1 %cmp, label %if.then, label %if.end, !dbg !28 |
| |
| if.then: ; preds = %entry |
| %mul = shl nsw i32 %foo.0.5, 1, !dbg !29 |
| call void @llvm.dbg.value(metadata i32 %mul, metadata !15, metadata !DIExpression()), !dbg !25 |
| %add = or i32 %mul, 1, !dbg !31 |
| call void @llvm.dbg.value(metadata i32 %add, metadata !15, metadata !DIExpression()), !dbg !25 |
| br label %if.end, !dbg !32 |
| |
| if.end: ; preds = %if.then, %entry |
| %brains.0 = phi i32 [ %add, %if.then ], [ %foo.0.5, %entry ], !dbg !33 |
| call void @llvm.dbg.value(metadata i32 %brains.0, metadata !15, metadata !DIExpression()), !dbg !25 |
| ret i32 %brains.0, !dbg !35 |
| } |
| |
| declare void @llvm.dbg.value(metadata, metadata, metadata) #2 |
| |
| !llvm.dbg.cu = !{!0} |
| !llvm.module.flags = !{!3, !4, !5} |
| !llvm.ident = !{!6} |
| |
| !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 8.0.0 (trunk 343753)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None) |
| !1 = !DIFile(filename: "pr38762.cpp", directory: ".") |
| !2 = !{} |
| !3 = !{i32 2, !"Dwarf Version", i32 4} |
| !4 = !{i32 2, !"Debug Info Version", i32 3} |
| !5 = !{i32 1, !"wchar_size", i32 4} |
| !6 = !{!"clang version 8.0.0 (trunk 343753)"} |
| !7 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !11) |
| !8 = !DISubroutineType(types: !9) |
| !9 = !{!10} |
| !10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) |
| !11 = !{!15} |
| !13 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !10) |
| !15 = !DILocalVariable(name: "brains", scope: !7, file: !1, line: 4, type: !10) |
| !25 = !DILocation(line: 4, scope: !7) |
| !26 = !DILocation(line: 6, scope: !27) |
| !27 = distinct !DILexicalBlock(scope: !7, file: !1, line: 6) |
| !28 = !DILocation(line: 6, scope: !7) |
| !29 = !DILocation(line: 7, scope: !30) |
| !30 = distinct !DILexicalBlock(scope: !27, file: !1, line: 6) |
| !31 = !DILocation(line: 8, scope: !30) |
| !32 = !DILocation(line: 9, scope: !30) |
| !33 = !DILocation(line: 0, scope: !7) |
| !34 = !DILocation(line: 12, scope: !7) |
| !35 = !DILocation(line: 11, scope: !7) |