[clang] 2f50a99 - [CIR] Fix error in cir.label when using cir.br in entry block (#163280)
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Tue Oct 14 17:57:55 PDT 2025
Author: Andres-Salamanca
Date: 2025-10-14T19:57:52-05:00
New Revision: 2f50a9913552d41ae93af5e9a8c1927b0f4b3833
URL: https://github.com/llvm/llvm-project/commit/2f50a9913552d41ae93af5e9a8c1927b0f4b3833
DIFF: https://github.com/llvm/llvm-project/commit/2f50a9913552d41ae93af5e9a8c1927b0f4b3833.diff
LOG: [CIR] Fix error in cir.label when using cir.br in entry block (#163280)
This PR fixes an error I found while working on cir.indirectbr. The
issue occurs when a branching operator points to the entry block LLVM’s
verifier does not allow this.
This PR is the same as the one I submitted in the
incubator:https://github.com/llvm/clangir/pull/1939
Added:
Modified:
clang/lib/CIR/CodeGen/CIRGenStmt.cpp
clang/test/CIR/CodeGen/goto.cpp
clang/test/CIR/CodeGen/label.c
Removed:
################################################################################
diff --git a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
index cfd48a227ed20..5ba64ddb85272 100644
--- a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
@@ -536,7 +536,7 @@ mlir::LogicalResult CIRGenFunction::emitLabel(const clang::LabelDecl &d) {
mlir::Block *currBlock = builder.getBlock();
mlir::Block *labelBlock = currBlock;
- if (!currBlock->empty()) {
+ if (!currBlock->empty() || currBlock->isEntryBlock()) {
{
mlir::OpBuilder::InsertionGuard guard(builder);
labelBlock = builder.createBlock(builder.getBlock()->getParent());
diff --git a/clang/test/CIR/CodeGen/goto.cpp b/clang/test/CIR/CodeGen/goto.cpp
index 48cb44ed0f478..257c2550c2399 100644
--- a/clang/test/CIR/CodeGen/goto.cpp
+++ b/clang/test/CIR/CodeGen/goto.cpp
@@ -205,6 +205,8 @@ extern "C" void case_follow_label(int v) {
// CIR: cir.func dso_local @case_follow_label
// CIR: cir.switch
// CIR: cir.case(equal, [#cir.int<1> : !s32i]) {
+// CIR: cir.br ^bb1
+// CIR: ^bb1:
// CIR: cir.label "label"
// CIR: cir.case(equal, [#cir.int<2> : !s32i]) {
// CIR: cir.call @action1()
@@ -215,9 +217,11 @@ extern "C" void case_follow_label(int v) {
// LLVM: define dso_local void @case_follow_label
// LLVM: switch i32 {{.*}}, label %[[SWDEFAULT:.*]] [
-// LLVM: i32 1, label %[[LABEL:.*]]
+// LLVM: i32 1, label %[[CASE1:.*]]
// LLVM: i32 2, label %[[CASE2:.*]]
// LLVM: ]
+// LLVM: [[CASE1]]:
+// LLVM: br label %[[LABEL:.*]]
// LLVM: [[LABEL]]:
// LLVM: br label %[[CASE2]]
// LLVM: [[CASE2]]:
@@ -303,3 +307,24 @@ extern "C" void default_follow_label(int v) {
// OGCG: br label %label
// OGCG: sw.epilog:
// OGCG: ret void
+
+void g3() {
+label:
+ goto label;
+}
+
+// CIR: cir.func dso_local @_Z2g3v
+// CIR: cir.br ^bb1
+// CIR: ^bb1:
+// CIR: cir.label "label"
+// CIR: cir.goto "label"
+
+// LLVM: define dso_local void @_Z2g3v()
+// LLVM: br label %1
+// LLVM: 1:
+// LLVM: br label %1
+
+// OGCG: define dso_local void @_Z2g3v()
+// OGCG: br label %label
+// OGCG: label:
+// OGCG: br label %label
diff --git a/clang/test/CIR/CodeGen/label.c b/clang/test/CIR/CodeGen/label.c
index a050094de678b..f5345efdccc47 100644
--- a/clang/test/CIR/CodeGen/label.c
+++ b/clang/test/CIR/CodeGen/label.c
@@ -11,10 +11,14 @@ void label() {
}
// CIR: cir.func no_proto dso_local @label
+// CIR: cir.br ^bb1
+// CIR: ^bb1:
// CIR: cir.label "labelA"
// CIR: cir.return
// LLVM:define dso_local void @label
+// LLVM: br label %1
+// LLVM: 1:
// LLVM: ret void
// OGCG: define dso_local void @label
@@ -29,15 +33,19 @@ void multiple_labels() {
}
// CIR: cir.func no_proto dso_local @multiple_labels
-// CIR: cir.label "labelB"
// CIR: cir.br ^bb1
-// CIR: ^bb1: // pred: ^bb0
+// CIR: ^bb1:
+// CIR: cir.label "labelB"
+// CIR: cir.br ^bb2
+// CIR: ^bb2:
// CIR: cir.label "labelC"
// CIR: cir.return
// LLVM: define dso_local void @multiple_labels()
// LLVM: br label %1
// LLVM: 1:
+// LLVM: br label %2
+// LLVM: 2:
// LLVM: ret void
// OGCG: define dso_local void @multiple_labels
@@ -56,6 +64,8 @@ void label_in_if(int cond) {
// CIR: cir.func dso_local @label_in_if
// CIR: cir.if {{.*}} {
+// CIR: cir.br ^bb1
+// CIR: ^bb1:
// CIR: cir.label "labelD"
// CIR: [[LOAD:%.*]] = cir.load align(4) [[COND:%.*]] : !cir.ptr<!s32i>, !s32i
// CIR: [[INC:%.*]] = cir.unary(inc, %3) nsw : !s32i, !s32i
@@ -68,15 +78,17 @@ void label_in_if(int cond) {
// LLVM: 3:
// LLVM: [[LOAD:%.*]] = load i32, ptr [[COND:%.*]], align 4
// LLVM: [[CMP:%.*]] = icmp ne i32 [[LOAD]], 0
-// LLVM: br i1 [[CMP]], label %6, label %9
+// LLVM: br i1 [[CMP]], label %6, label %10
// LLVM: 6:
+// LLVM: br label %7
+// LLVM: 7:
// LLVM: [[LOAD2:%.*]] = load i32, ptr [[COND]], align 4
// LLVM: [[ADD1:%.*]] = add nsw i32 [[LOAD2]], 1
// LLVM: store i32 [[ADD1]], ptr [[COND]], align 4
-// LLVM: br label %9
-// LLVM: 9:
// LLVM: br label %10
// LLVM: 10:
+// LLVM: br label %11
+// LLVM: 11:
// LLVM: ret void
// OGCG: define dso_local void @label_in_if
@@ -142,11 +154,15 @@ void labelWithoutMatch() {
return;
}
// CIR: cir.func no_proto dso_local @labelWithoutMatch
+// CIR: cir.br ^bb1
+// CIR: ^bb1:
// CIR: cir.label "end"
// CIR: cir.return
// CIR: }
// LLVM: define dso_local void @labelWithoutMatch
+// LLVM: br label %1
+// LLVM: 1:
// LLVM: ret void
// OGCG: define dso_local void @labelWithoutMatch
@@ -167,13 +183,17 @@ void foo() {
// CIR: cir.func no_proto dso_local @foo
// CIR: cir.scope {
-// CIR: cir.label "label"
// CIR: %0 = cir.alloca !rec_S, !cir.ptr<!rec_S>, ["agg.tmp0"]
+// CIR: cir.br ^bb1
+// CIR: ^bb1:
+// CIR: cir.label "label"
// LLVM:define dso_local void @foo() {
// LLVM: [[ALLOC:%.*]] = alloca %struct.S, i64 1, align 1
// LLVM: br label %2
// LLVM:2:
+// LLVM: br label %3
+// LLVM:3:
// LLVM: [[CALL:%.*]] = call %struct.S @get()
// LLVM: store %struct.S [[CALL]], ptr [[ALLOC]], align 1
// LLVM: [[LOAD:%.*]] = load %struct.S, ptr [[ALLOC]], align 1
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