From ff35f1dcd38b15cd045f091691c7fdcf75b53d0f Mon Sep 17 00:00:00 2001 From: Taewook Oh Date: Tue, 21 Feb 2017 00:12:38 +0000 Subject: [PATCH] [BranchFolding] Update debug location along with the update of branch instruction. Summary: Currently, BranchFolder drops DebugLoc for branch instructions in some places. For example, for the test code attached, the branch instruction of 'entry' block has a DILocation of ``` !12 = !DILocation(line: 6, column: 3, scope: !11) ``` , but this information is gone when then block is lowered because BranchFolder misses it. This patch is a fix for this issue. Reviewers: qcolombet, aprantl, craig.topper, MatzeB Reviewed By: aprantl Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D29902 llvm-svn: 295684 --- lib/CodeGen/BranchFolding.cpp | 6 +- test/CodeGen/X86/branchfolding-debugloc.ll | 83 ++++++++++++++++++++++ 2 files changed, 86 insertions(+), 3 deletions(-) create mode 100644 test/CodeGen/X86/branchfolding-debugloc.ll diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp index b347ea31394..08aafda4bd8 100644 --- a/lib/CodeGen/BranchFolding.cpp +++ b/lib/CodeGen/BranchFolding.cpp @@ -389,7 +389,7 @@ MachineBasicBlock *BranchFolder::SplitMBBAt(MachineBasicBlock &CurMBB, NewMBB->splice(NewMBB->end(), &CurMBB, BBI1, CurMBB.end()); // NewMBB belongs to the same loop as CurMBB. - if (MLI) + if (MLI) if (MachineLoop *ML = MLI->getLoopFor(&CurMBB)) ML->addBasicBlockToLoop(NewMBB, MLI->getBase()); @@ -437,7 +437,7 @@ static void FixTail(MachineBasicBlock *CurMBB, MachineBasicBlock *SuccBB, MachineFunction::iterator I = std::next(MachineFunction::iterator(CurMBB)); MachineBasicBlock *TBB = nullptr, *FBB = nullptr; SmallVector Cond; - DebugLoc dl; // FIXME: this is nowhere + DebugLoc dl = CurMBB->findBranchDebugLoc(); if (I != MF->end() && !TII->analyzeBranch(*CurMBB, TBB, FBB, Cond, true)) { MachineBasicBlock *NextBB = &*I; if (TBB == NextBB && !Cond.empty() && !FBB) { @@ -1073,7 +1073,7 @@ bool BranchFolder::TailMergeBlocks(MachineFunction &MF) { // Remove the unconditional branch at the end, if any. if (TBB && (Cond.empty() || FBB)) { - DebugLoc dl; // FIXME: this is nowhere + DebugLoc dl = PBB->findBranchDebugLoc(); TII->removeBranch(*PBB); if (!Cond.empty()) // reinsert conditional branch only, for now diff --git a/test/CodeGen/X86/branchfolding-debugloc.ll b/test/CodeGen/X86/branchfolding-debugloc.ll new file mode 100644 index 00000000000..3ad8315f083 --- /dev/null +++ b/test/CodeGen/X86/branchfolding-debugloc.ll @@ -0,0 +1,83 @@ +; RUN: llc < %s | FileCheck %s +; +; The test code is generated from the following source code: +; +; 1 extern int bar(int x); +; 2 +; 3 int foo(int *begin, int *end) { +; 4 int *i; +; 5 int ret = 0; +; 6 for ( +; 7 i = begin ; +; 8 i != end ; +; 9 i++) +; 10 { +; 11 ret += bar(*i); +; 12 } +; 13 return ret; +; 14 } +; +; CHECK: # %entry +; CHECK-NOT: # %for.body +; CHECK: .loc 1 6 3 +; CHECK-NEXT: je [[BB:.LBB[^ ]+]] +; CHECK: [[BB]]:{{.}}# %for.end + +target triple = "x86_64-unknown-linux-gnu" + +define i32 @foo(i32* readonly %begin, i32* readnone %end) !dbg !4 { +entry: + %cmp6 = icmp eq i32* %begin, %end, !dbg !9 + br i1 %cmp6, label %for.end, label %for.body.preheader, !dbg !12 + +for.body.preheader: ; preds = %entry + br label %for.body, !dbg !13 + +for.body: ; preds = %for.body.preheader, %for.body + %ret.08 = phi i32 [ %add, %for.body ], [ 0, %for.body.preheader ] + %i.07 = phi i32* [ %incdec.ptr, %for.body ], [ %begin, %for.body.preheader ] + %0 = load i32, i32* %i.07, align 4, !dbg !13, !tbaa !15 + %call = tail call i32 @bar(i32 %0), !dbg !19 + %add = add nsw i32 %call, %ret.08, !dbg !20 + %incdec.ptr = getelementptr inbounds i32, i32* %i.07, i64 1, !dbg !21 + %cmp = icmp eq i32* %incdec.ptr, %end, !dbg !9 + br i1 %cmp, label %for.end.loopexit, label %for.body, !dbg !12, !llvm.loop !22 + +for.end.loopexit: ; preds = %for.body + br label %for.end, !dbg !24 + +for.end: ; preds = %for.end.loopexit, %entry + %ret.0.lcssa = phi i32 [ 0, %entry ], [ %add, %for.end.loopexit ] + ret i32 %ret.0.lcssa, !dbg !24 +} + +declare i32 @bar(i32) + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!2, !3} + +!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, emissionKind: FullDebug) +!1 = !DIFile(filename: "foo.c", directory: "b/") +!2 = !{i32 2, !"Dwarf Version", i32 4} +!3 = !{i32 2, !"Debug Info Version", i32 3} +!4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 3, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !0) +!5 = !DISubroutineType(types: !6) +!6 = !{!7, !8, !8} +!7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!8 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !7, size: 64) +!9 = !DILocation(line: 8, column: 9, scope: !10) +!10 = distinct !DILexicalBlock(scope: !11, file: !1, line: 6, column: 3) +!11 = distinct !DILexicalBlock(scope: !4, file: !1, line: 6, column: 3) +!12 = !DILocation(line: 6, column: 3, scope: !11) +!13 = !DILocation(line: 11, column: 18, scope: !14) +!14 = distinct !DILexicalBlock(scope: !10, file: !1, line: 10, column: 3) +!15 = !{!16, !16, i64 0} +!16 = !{!"int", !17, i64 0} +!17 = !{!"omnipotent char", !18, i64 0} +!18 = !{!"Simple C/C++ TBAA"} +!19 = !DILocation(line: 11, column: 14, scope: !14) +!20 = !DILocation(line: 11, column: 11, scope: !14) +!21 = !DILocation(line: 9, column: 8, scope: !10) +!22 = distinct !{!22, !12, !23} +!23 = !DILocation(line: 12, column: 3, scope: !11) +!24 = !DILocation(line: 13, column: 3, scope: !4)