[llvm-branch-commits] [llvm] [KeyInstr][JumpThreading] Remap atoms after threading (PR #133487)

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Fri Mar 28 11:00:49 PDT 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-debuginfo

Author: Orlando Cazalet-Hyams (OCHyams)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/133487.diff


3 Files Affected:

- (modified) llvm/lib/Transforms/Scalar/JumpThreading.cpp (+1) 
- (modified) llvm/test/DebugInfo/KeyInstructions/Generic/jump-threading-2-bbs.ll (+23-7) 
- (added) llvm/test/DebugInfo/KeyInstructions/Generic/jump-threading-basic.ll (+78) 


``````````diff
diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
index 18dda2f3ad82e..d320f7dce11db 100644
--- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
@@ -2451,6 +2451,7 @@ void JumpThreadingPass::threadEdge(BasicBlock *BB,
                                {DominatorTree::Insert, PredBB, NewBB},
                                {DominatorTree::Delete, PredBB, BB}});
 
+  remapSourceAtoms(ValueMapping, NewBB->begin(), NewBB->end());
   updateSSA(BB, NewBB, ValueMapping);
 
   // At this point, the IR is fully up to date and consistent.  Do a quick scan
diff --git a/llvm/test/DebugInfo/KeyInstructions/Generic/jump-threading-2-bbs.ll b/llvm/test/DebugInfo/KeyInstructions/Generic/jump-threading-2-bbs.ll
index 3ca81f554034f..612e74792fac2 100644
--- a/llvm/test/DebugInfo/KeyInstructions/Generic/jump-threading-2-bbs.ll
+++ b/llvm/test/DebugInfo/KeyInstructions/Generic/jump-threading-2-bbs.ll
@@ -2,27 +2,41 @@
 
 ;; Modified from llvm/test/Transforms/JumpThreading/thread-two-bbs.ll
 ;;
-;; JumpThreading duplicates bb.cond2 to thread through bb.file to bb.f2 or exit.
+;; JumpThreading duplicates bb.cond2 to thread through bb.file to bb.file,
+;; bb.f2 or exit.
 ;;
 ;; Check the duplicated instructions get remapped atom groups.
 
 ; CHECK: bb.cond2:
 ; CHECK-NEXT: call void @f1()
 ; CHECK-NEXT: %tobool1 = icmp eq i32 %cond2, 0, !dbg [[G1R2:!.*]]
-; CHECK-NEXT: br i1 %tobool1, label %exit, label %exit, !dbg [[G1R1:!.*]]
+; CHECK-NEXT: br i1 %tobool1, label %bb.file, label %exit, !dbg [[G1R1:!.*]]
 
 ; CHECK: bb.cond2.thread:
-; CHECK-NEXT: %tobool12 = icmp eq i32 %cond2, 0, !dbg [[G2R2:!.*]]
-; CHECK-NEXT: br i1 %tobool12, label %bb.f2, label %exit, !dbg [[G2R1:!.*]]
+; CHECK-NEXT: %tobool12 = icmp eq i32 %cond2, 0, !dbg [[G3R2:!.*]]
+; CHECK-NEXT: br i1 %tobool12, label %bb.f2, label %exit, !dbg [[G3R1:!.*]]
+
+;; After the transform %ptr is null through bb.cond2 and @a through
+;; bb.cond2.thread. Thread bb.cond2.thread->bb.f2 through bb.file.
+;; Check the duplicated store gets a remapped atom group too.
+
+; CHECK: bb.file:
+; CHECK-NEXT: %ptr3 = phi ptr [ null, %bb.cond2 ]
+; CHECK-NEXT: store ptr %ptr3, ptr %p, align 4, !dbg [[G2R1:!.*]]
+
+; CHECK: bb.f2:
+; CHECK-NEXT: store ptr @a, ptr %p, align 4, !dbg [[G4R1:!.*]]
 
 ; CHECK: [[G1R2]] = !DILocation(line: 1, column: 1, scope: ![[#]], atomGroup: 1, atomRank: 2)
 ; CHECK: [[G1R1]] = !DILocation(line: 1, column: 1, scope: ![[#]], atomGroup: 1, atomRank: 1)
-; CHECK: [[G2R2]] = !DILocation(line: 1, column: 1, scope: ![[#]], atomGroup: 2, atomRank: 2)
-; CHECK: [[G2R1]] = !DILocation(line: 1, column: 1, scope: ![[#]], atomGroup: 2, atomRank: 1)
+; CHECK: [[G3R2]] = !DILocation(line: 1, column: 1, scope: ![[#]], atomGroup: 3, atomRank: 2)
+; CHECK: [[G3R1]] = !DILocation(line: 1, column: 1, scope: ![[#]], atomGroup: 3, atomRank: 1)
+; CHECK: [[G2R1]] = !DILocation(line: 2, column: 1, scope: ![[#]], atomGroup: 2, atomRank: 1)
+; CHECK: [[G4R1]] = !DILocation(line: 2, column: 1, scope: ![[#]], atomGroup: 4, atomRank: 1)
 
 @a = global i32 0, align 4
 
-define void @foo(i32 %cond1, i32 %cond2) !dbg !5 {
+define void @foo(i32 %cond1, i32 %cond2, ptr %p) !dbg !5 {
 entry:
   %tobool = icmp eq i32 %cond1, 0
   br i1 %tobool, label %bb.cond2, label %bb.f1
@@ -37,6 +51,7 @@ bb.cond2:                                         ; preds = %bb.f1, %entry
   br i1 %tobool1, label %bb.file, label %exit, !dbg !10
 
 bb.file:                                          ; preds = %bb.cond2
+  store ptr %ptr, ptr %p, align 4, !dbg !11
   %cmp = icmp eq ptr %ptr, null
   br i1 %cmp, label %exit, label %bb.f2
 
@@ -66,3 +81,4 @@ declare void @f2()
 !7 = !{}
 !9 = !DILocation(line: 1, column: 1, scope: !5, atomGroup: 1, atomRank: 2)
 !10 = !DILocation(line: 1, column: 1, scope: !5, atomGroup: 1, atomRank: 1)
+!11 = !DILocation(line: 2, column: 1, scope: !5, atomGroup: 2, atomRank: 1)
diff --git a/llvm/test/DebugInfo/KeyInstructions/Generic/jump-threading-basic.ll b/llvm/test/DebugInfo/KeyInstructions/Generic/jump-threading-basic.ll
new file mode 100644
index 0000000000000..d653a8d525b79
--- /dev/null
+++ b/llvm/test/DebugInfo/KeyInstructions/Generic/jump-threading-basic.ll
@@ -0,0 +1,78 @@
+; RUN: opt %s --passes=jump-threading -S -o - -S | FileCheck %s
+
+;;        +-> T1 -+
+;;        |       v      +-> T2
+;; Entry -+       Merge -+
+;;        |       ^      +-> F2
+;;        +-> F1 -+
+;;
+;; Thread T1 -> T2 and F1 -> F2 through Merge.
+;;
+;;        +-> T1
+;;        |
+;; Entry -+
+;;        |
+;;        +-> F1
+;;
+;; Check the duplicated instructions atoms are remapped.
+
+; CHECK: T2:
+; CHECK-NEXT: %v1 = call i32 @f1()
+; CHECK-NEXT: %C3 = add i32 %v1, 1, !dbg [[G2R2:!.*]]
+; CHECK-NEXT: store i32 %C3, ptr %p, align 4, !dbg [[G2R1:!.*]]
+
+; CHECK: F2:
+; CHECK-NEXT: %v2 = call i32 @f2()
+; CHECK-NEXT: %C = add i32 %v2, 1, !dbg [[G1R2:!.*]]
+; CHECK-NEXT: store i32 %C, ptr %p, align 4, !dbg [[G1R1:!.*]]
+
+; CHECK: [[G2R2]] = !DILocation(line: 8, column: 1, scope: ![[#]], atomGroup: 2, atomRank: 2)
+; CHECK: [[G2R1]] = !DILocation(line: 8, column: 1, scope: ![[#]], atomGroup: 2, atomRank: 1)
+; CHECK: [[G1R2]] = !DILocation(line: 8, column: 1, scope: ![[#]], atomGroup: 1, atomRank: 2)
+; CHECK: [[G1R1]] = !DILocation(line: 8, column: 1, scope: ![[#]], atomGroup: 1, atomRank: 1)
+
+define i32 @test1(i1 %cond, ptr %p) !dbg !5 {
+  br i1 %cond, label %T1, label %F1
+
+T1:                                               ; preds = %0
+  %v1 = call i32 @f1()
+  br label %Merge
+
+F1:                                               ; preds = %0
+  %v2 = call i32 @f2()
+  br label %Merge
+
+Merge:                                            ; preds = %F1, %T1
+  %A = phi i1 [ true, %T1 ], [ false, %F1 ]
+  %B = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
+  %C = add i32 %B, 1, !dbg !8
+  store i32 %C, ptr %p, align 4, !dbg !9
+  br i1 %A, label %T2, label %F2
+
+T2:                                               ; preds = %Merge
+  call void @f3()
+  ret i32 %B
+
+F2:                                               ; preds = %Merge
+  ret i32 %B
+}
+
+declare i32 @f1()
+declare i32 @f2()
+declare void @f3()
+
+!llvm.dbg.cu = !{!0}
+!llvm.debugify = !{!2, !3}
+!llvm.module.flags = !{!4}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
+!1 = !DIFile(filename: "test.ll", directory: "/")
+!2 = !{i32 12}
+!3 = !{i32 0}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = distinct !DISubprogram(name: "test1", linkageName: "test1", scope: null, file: !1, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0)
+!6 = !DISubroutineType(types: !7)
+!7 = !{}
+!8 = !DILocation(line: 8, column: 1, scope: !5, atomGroup: 1, atomRank: 2)
+!9 = !DILocation(line: 8, column: 1, scope: !5, atomGroup: 1, atomRank: 1)
+

``````````

</details>


https://github.com/llvm/llvm-project/pull/133487


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