diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp index 6f5afbd2a996a..d10e6722f4548 100644 --- a/llvm/lib/CodeGen/BranchFolding.cpp +++ b/llvm/lib/CodeGen/BranchFolding.cpp @@ -2071,7 +2071,38 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) { if (!HasDups) return false; - MBB->splice(Loc, TBB, TBB->begin(), TIB); + // Hoist the instructions from [T.begin, TIB) and then delete [F.begin, FIB). + // Merge the debug locations. FIXME: We should do something with the + // debug instructions too (from BOTH branches). + { + // TIB and FIB point to the end of the regions to hoist/merge in TBB and + // FBB. + MachineBasicBlock::iterator FE = FIB; + MachineBasicBlock::iterator FI = FBB->begin(); + for (MachineBasicBlock::iterator TI : + make_early_inc_range(make_range(TBB->begin(), TIB))) { + // Move debug instructions and pseudo probes without modifying them. + // FIXME: This is the wrong thing to do for debug locations, which + // should at least be killed. + if (TI->isDebugOrPseudoInstr()) { + TI->moveBefore(&*Loc); + continue; + } + + // Get the next non-meta instruction in FBB. + FI = skipDebugInstructionsForward(FI, FE, false); + // NOTE: The loop above checks CheckKillDead but we can't do that here as + // it modifies some kill markers after the check. + assert(TI->isIdenticalTo(*FI, MachineInstr::CheckDefs) && + "Expected non-debug lockstep"); + + // Merge debug locs on hoisted instructions. + TI->setDebugLoc( + DILocation::getMergedLocation(TI->getDebugLoc(), FI->getDebugLoc())); + TI->moveBefore(&*Loc); + ++FI; + } + } FBB->erase(FBB->begin(), FIB); if (UpdateLiveIns) diff --git a/llvm/test/DebugInfo/X86/branch-folder-dbg.mir b/llvm/test/DebugInfo/X86/branch-folder-dbg.mir new file mode 100644 index 0000000000000..5c38fd2a43829 --- /dev/null +++ b/llvm/test/DebugInfo/X86/branch-folder-dbg.mir @@ -0,0 +1,111 @@ +# RUN: llc %s --start-before=branch-folder --stop-after=branch-folder -o - | FileCheck %s + +## Check that common instructions hoisted from `if.then` and `if.else` into +## common pred `entry` get merged debug locations. + +## FIXME: The debug instructions handling here is wrong. + +# CHECK: bb.0 +# CHECK: CALL64pcrel32 @f, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax +## --- Start splice from bb.2.if.else --- +# CHECK-NEXT: DBG_VALUE 2, $noreg, ![[#]], !DIExpression(), debug-location ![[#]] +# CHECK-NEXT: $edi = MOV32r0 implicit-def dead $eflags, debug-location !DILocation(line: 0, scope: ![[#]]) +## --- End splice -------------- +# CHECK-NEXT: TEST64rr killed renamable $rax, renamable $rax, implicit-def $eflags +# CHECK-NEXT: JCC_1 %bb.2, 9, implicit killed $eflags +# CHECK: bb.1 + +--- | + target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" + target triple = "x86_64-unknown-linux-gnu" + + declare dso_local noundef i64 @f() local_unnamed_addr + + define dso_local noundef i32 @g() local_unnamed_addr !dbg !7 { + %call = tail call noundef i64 @f() + %cmp1 = icmp sgt i64 0, %call + %conv2 = trunc i64 0 to i32 + br i1 %cmp1, label %if.then, label %if.else + + if.then: ; preds = %0 + #dbg_value(i64 0, !11, !DIExpression(), !13) + tail call void @_Z3fooii(i32 noundef %conv2, i32 noundef 0), !dbg !14 + #dbg_value(i64 1, !11, !DIExpression(), !13) + br label %if.end, !dbg !15 + + if.else: ; preds = %0 + #dbg_value(i64 2, !11, !DIExpression(), !13) + tail call void @_Z3barii(i32 noundef %conv2, i32 noundef 1), !dbg !16 + #dbg_value(i64 3, !11, !DIExpression(), !13) + br label %if.end, !dbg !17 + + if.end: ; preds = %if.else, %if.then + ret i32 2 + } + + declare void @_Z3fooii(i32 noundef, i32 noundef) local_unnamed_addr + + declare void @_Z3barii(i32 noundef, i32 noundef) local_unnamed_addr + + !llvm.module.flags = !{!0, !1} + !llvm.ident = !{!2} + !llvm.dbg.cu = !{!3} + !llvm.debugify = !{!5, !6} + + !0 = !{i32 7, !"Dwarf Version", i32 5} + !1 = !{i32 2, !"Debug Info Version", i32 3} + !2 = !{!"clang version 21.0.0"} + !3 = distinct !DICompileUnit(language: DW_LANG_C, file: !4, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug) + !4 = !DIFile(filename: "test.nodbg.ll", directory: "/") + !5 = !{i32 15} + !6 = !{i32 7} + !7 = distinct !DISubprogram(name: "g", linkageName: "g", scope: null, file: !4, line: 1, type: !8, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !3, retainedNodes: !10) + !8 = !DISubroutineType(types: !9) + !9 = !{} + !10 = !{!11} + !11 = !DILocalVariable(name: "1", scope: !7, file: !4, line: 3, type: !12) + !12 = !DIBasicType(name: "ty64", size: 64, encoding: DW_ATE_unsigned) + !13 = !DILocation(line: 3, column: 1, scope: !7) + !14 = !DILocation(line: 9, column: 1, scope: !7) + !15 = !DILocation(line: 10, column: 1, scope: !7) + !16 = !DILocation(line: 11, column: 1, scope: !7) + !17 = !DILocation(line: 12, column: 1, scope: !7) +... +--- +name: g +body: | + bb.0 (%ir-block.0): + successors: %bb.1(0x40000000), %bb.2(0x40000000) + + frame-setup PUSH64r undef $rax, implicit-def $rsp, implicit $rsp + frame-setup CFI_INSTRUCTION def_cfa_offset 16 + CALL64pcrel32 @f, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax + TEST64rr killed renamable $rax, renamable $rax, implicit-def $eflags + JCC_1 %bb.2, 9, implicit killed $eflags + JMP_1 %bb.1 + + bb.1.if.then: + successors: %bb.3(0x80000000) + + DBG_VALUE 0, $noreg, !11, !DIExpression(), debug-location !13 + $edi = MOV32r0 implicit-def dead $eflags, debug-location !14 + $esi = MOV32r0 implicit-def dead $eflags, debug-location !14 + CALL64pcrel32 target-flags(x86-plt) @_Z3fooii, csr_64, implicit $rsp, implicit $ssp, implicit killed $edi, implicit killed $esi, implicit-def $rsp, implicit-def $ssp, debug-location !14 + DBG_VALUE 1, $noreg, !11, !DIExpression(), debug-location !13 + JMP_1 %bb.3, debug-location !15 + + bb.2.if.else: + successors: %bb.3(0x80000000) + + DBG_VALUE 2, $noreg, !11, !DIExpression(), debug-location !13 + $edi = MOV32r0 implicit-def dead $eflags, debug-location !16 + $esi = MOV32ri 1, debug-location !16 + CALL64pcrel32 target-flags(x86-plt) @_Z3barii, csr_64, implicit $rsp, implicit $ssp, implicit killed $edi, implicit killed $esi, implicit-def $rsp, implicit-def $ssp, debug-location !16 + DBG_VALUE 3, $noreg, !11, !DIExpression(), debug-location !13 + + bb.3.if.end: + $eax = MOV32ri 2 + $rcx = frame-destroy POP64r implicit-def $rsp, implicit $rsp + frame-destroy CFI_INSTRUCTION def_cfa_offset 8 + RET 0, $eax +...