[llvm] 41aed21 - [CoroSplit][DebugInfo] Fix scope of continuation funclets (#180523)

[via llvm-commits]

Author: Felipe de Azevedo Piovezan
Date: 2026-02-10T10:45:02Z
New Revision: 41aed214a09d4e7f8e2bfe0f6fa36ae43556761d

URL: https://github.com/llvm/llvm-project/commit/41aed214a09d4e7f8e2bfe0f6fa36ae43556761d
DIFF: https://github.com/llvm/llvm-project/commit/41aed214a09d4e7f8e2bfe0f6fa36ae43556761d.diff

LOG: [CoroSplit][DebugInfo] Fix scope of continuation funclets (#180523)

The heuristic for deciding which scope line to use for a continuation
funclet relies on iterating on the instructions of the first BB of the
continuation. Often, this contains a single unconditional branch, which
is skipped by the heuristic. However, in coro-retcon, two such
"jump-only" BBs are generated. This patch amends the heuristic to
account for that.

Added: 
    llvm/test/Transforms/Coroutines/coro-retcon-continuation-scope.ll

Modified: 
    llvm/lib/Transforms/Coroutines/CoroSplit.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
index c2d7bcc346776..f83b6a601572d 100644
--- a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -815,9 +815,11 @@ static void updateScopeLine(Instruction *ActiveSuspend,
   BasicBlock::iterator Successor = ActiveSuspend->getNextNode()->getIterator();
   // Corosplit splits the BB around ActiveSuspend, so the meaningful
   // instructions are not in the same BB.
-  if (auto *Branch = dyn_cast_or_null<BranchInst>(Successor);
-      Branch && Branch->isUnconditional())
+  while (auto *Branch = dyn_cast_or_null<BranchInst>(Successor)) {
+    if (!Branch->isUnconditional())
+      break;
     Successor = Branch->getSuccessor(0)->getFirstNonPHIOrDbg();
+  }
 
   // Find the first successor of ActiveSuspend with a non-zero line location.
   // If that matches the file of ActiveSuspend, use it.

diff  --git a/llvm/test/Transforms/Coroutines/coro-retcon-continuation-scope.ll b/llvm/test/Transforms/Coroutines/coro-retcon-continuation-scope.ll
new file mode 100644
index 0000000000000..c037ffc16468c
--- /dev/null
+++ b/llvm/test/Transforms/Coroutines/coro-retcon-continuation-scope.ll
@@ -0,0 +1,69 @@
+; RUN: opt < %s -passes='cgscc(coro-split),simplifycfg,early-cse' -S | FileCheck %s
+
+@"coroutineTwc" = global <{ i32, i32, i64 }> <{ i32 trunc (i64 sub (i64 ptrtoint (ptr @"coroutine" to i64), i64 ptrtoint (ptr @"coroutineTwc" to i64)) to i32), i32 0, i64 51979 }>, align 8
+
+define swiftcc { ptr, ptr } @"coroutine"(ptr noalias %0, ptr %1, ptr swiftself %2) #0 !dbg !39 {
+entry:
+  %3 = call token @llvm.coro.id.retcon.once(i32 -1, i32 16, ptr %0, ptr @"$s4test1SVSiIetMIlYl_TC", ptr @_swift_coro_alloc, ptr @_swift_coro_dealloc), !dbg !48
+  %4 = call ptr @llvm.coro.begin(token %3, ptr null), !dbg !48
+  call swiftcc void @"$s4test6FINISHyyF"(), !dbg !50
+  %.member_int = getelementptr inbounds nuw <{ <{ i64 }> }>, ptr %2, i32 0, i32 0, !dbg !51
+; Test that the scope of the continuation is NOT on the same line as the split
+; point.
+; In this case the split point is on line 11, and the scope of the continuation
+; should be line 12.
+  %5 = call ptr (...) @llvm.coro.suspend.retcon.p0(ptr %.member_int), !dbg !52 ; [debug line = 11:7]
+; CHECK-LABEL: define {{.*}} @coroutine.resume
+; CHECK-SAME: !dbg ![[CONTINUATION_SP:[0-9]+]]
+; CHECK: ![[CONTINUATION_SP]] = {{.*}} scopeLine: 12
+  br i1 false, label %7, label %6, !dbg !52       ; [debug line = 11:7]
+
+6:
+  call swiftcc void @"$s4test6FINISHyyF"(), !dbg !53 ; [debug line = 12:7]
+  br label %coro.end, !dbg !54
+
+7:
+  br label %coro.end, !dbg !54
+
+coro.end:
+  call void @llvm.coro.end(ptr %4, i1 false, token none), !dbg !54
+  unreachable, !dbg !54
+}
+
+declare swiftcc void @"$s4test6FINISHyyF"()
+declare swiftcc ptr @_swift_coro_alloc(i64) #3
+declare swiftcc void @_swift_coro_dealloc(ptr) #3
+declare swiftcc ptr @_swift_coro_alloc_frame(ptr, ptr, i64, i64) #3
+declare swiftcc void @_swift_coro_dealloc_frame(ptr, ptr, ptr) #3
+declare swiftcc void @"$s4test1SVSiIetMIlYl_TC"(ptr noalias, ptr)
+
+attributes #0 = { noinline presplitcoroutine }
+attributes #3 = { noinline nounwind }
+
+!llvm.module.flags = !{!7, !8, !9, !10, !11}
+!llvm.dbg.cu = !{!17}
+
+!7 = !{i32 7, !"Dwarf Version", i32 5}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !{i32 1, !"wchar_size", i32 4}
+!10 = !{i32 8, !"PIC Level", i32 2}
+!11 = !{i32 7, !"uwtable", i32 1}
+!17 = distinct !DICompileUnit(language: DW_LANG_Swift, file: !18, producer: "Swift", isOptimized: false, emissionKind: FullDebug)
+!18 = !DIFile(filename: "test.ll", directory: "/")
+!39 = distinct !DISubprogram(name: "COMPUTED_PROPERTY.yielding_mutate", linkageName: "coroutine", scope: !40, file: !18, line: 9, type: !41, scopeLine: 9, spFlags: DISPFlagDefinition, unit: !17, declaration: !44, retainedNodes: !45)
+!40 = !DICompositeType(tag: DW_TAG_structure_type, name: "S", file: !18, size: 64, runtimeLang: DW_LANG_Swift, identifier: "$s4test1SVD")
+!41 = !DISubroutineType(types: !42)
+!42 = !{!43, !40}
+!43 = !DICompositeType(tag: DW_TAG_structure_type, name: "$sytD", flags: DIFlagFwdDecl, runtimeLang: DW_LANG_Swift, identifier: "$sytD")
+!44 = !DISubprogram(name: "COMPUTED_PROPERTY.yielding_mutate", linkageName: "coroutine", scope: !40, file: !18, line: 9, type: !41, scopeLine: 9, spFlags: 0)
+!45 = !{!46}
+!46 = !DILocalVariable(name: "self", arg: 1, scope: !39, file: !18, line: 9, type: !40, flags: DIFlagArtificial)
+!47 = !DILocation(line: 9, column: 14, scope: !39)
+!48 = !DILocation(line: 0, scope: !39)
+!50 = !DILocation(line: 10, column: 7, scope: !39)
+!51 = !DILocation(line: 11, column: 13, scope: !39)
+!52 = !DILocation(line: 11, column: 7, scope: !39)
+!53 = !DILocation(line: 12, column: 7, scope: !39)
+!54 = !DILocation(line: 0, scope: !55)
+!55 = !DILexicalBlockFile(scope: !39, file: !56, discriminator: 0)
+!56 = !DIFile(filename: "<compiler-generated>", directory: "/")