https://github.com/lijinpei-amd updated https://github.com/llvm/llvm-project/pull/201047
>From 7b9a14d8c80c4a5fe9f5a49e35af7b6af35a3fb9 Mon Sep 17 00:00:00 2001 From: Li Jinpei <[email protected]> Date: Tue, 2 Jun 2026 15:15:08 +0800 Subject: [PATCH] [clang][CodeGen] Fix crash on if/switch init-statement ending in noreturn EmitStmt may `ClearInsertionPoint()` to mark dead code; the condition emitted next assumes a valid insertion point. Restore one with `EnsureInsertPoint()` after the init statement. The if/switch body may still be reachable through a label, so it must be emitted rather than skipped. Fixes #115514. --- clang/lib/CodeGen/CGStmt.cpp | 14 ++- clang/test/CodeGenCXX/noreturn-init-stmt.cpp | 98 ++++++++++++++++++++ 2 files changed, 110 insertions(+), 2 deletions(-) create mode 100644 clang/test/CodeGenCXX/noreturn-init-stmt.cpp diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp index 30756180ebafa..232094777f233 100644 --- a/clang/lib/CodeGen/CGStmt.cpp +++ b/clang/lib/CodeGen/CGStmt.cpp @@ -885,9 +885,14 @@ void CodeGenFunction::EmitIfStmt(const IfStmt &S) { LexicalScope ConditionScope(*this, S.getCond()->getSourceRange()); ApplyDebugLocation DL(*this, S.getCond()); - if (S.getInit()) + if (S.getInit()) { EmitStmt(S.getInit()); + // The init statement may have cleared the insertion point (e.g. it ended in + // a 'noreturn' call); the condition emitted below needs a valid one. + EnsureInsertPoint(); + } + if (S.getConditionVariable()) EmitDecl(*S.getConditionVariable()); @@ -2374,9 +2379,14 @@ void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) { RunCleanupsScope ConditionScope(*this); - if (S.getInit()) + if (S.getInit()) { EmitStmt(S.getInit()); + // The init statement may have cleared the insertion point (e.g. it ended in + // a 'noreturn' call); the condition emitted below needs a valid one. + EnsureInsertPoint(); + } + if (S.getConditionVariable()) EmitDecl(*S.getConditionVariable()); llvm::Value *CondV = EmitScalarExpr(S.getCond()); diff --git a/clang/test/CodeGenCXX/noreturn-init-stmt.cpp b/clang/test/CodeGenCXX/noreturn-init-stmt.cpp new file mode 100644 index 0000000000000..ab857da974648 --- /dev/null +++ b/clang/test/CodeGenCXX/noreturn-init-stmt.cpp @@ -0,0 +1,98 @@ +// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 6 +// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o - | FileCheck %s + +struct T { + ~T(); +}; +[[noreturn]] void die(); +bool check(const T &); +int pick(const T &); + +// CHECK-LABEL: define dso_local noundef i32 @_Z4testb( +// CHECK-SAME: i1 noundef zeroext [[COND:%.*]]) #[[ATTR0:[0-9]+]] { +// CHECK-NEXT: [[ENTRY:.*:]] +// CHECK-NEXT: [[RETVAL:%.*]] = alloca i32, align 4 +// CHECK-NEXT: [[COND_ADDR:%.*]] = alloca i8, align 1 +// CHECK-NEXT: [[REF_TMP:%.*]] = alloca [[STRUCT_T:%.*]], align 1 +// CHECK-NEXT: [[STOREDV:%.*]] = zext i1 [[COND]] to i8 +// CHECK-NEXT: store i8 [[STOREDV]], ptr [[COND_ADDR]], align 1 +// CHECK-NEXT: [[TMP0:%.*]] = load i8, ptr [[COND_ADDR]], align 1 +// CHECK-NEXT: [[LOADEDV:%.*]] = icmp ne i8 [[TMP0]], 0 +// CHECK-NEXT: br i1 [[LOADEDV]], label %[[IF_THEN:.*]], label %[[IF_END:.*]] +// CHECK: [[IF_THEN]]: +// CHECK-NEXT: br label %[[LABEL:.*]] +// CHECK: [[IF_END]]: +// CHECK-NEXT: call void @_Z3diev() #[[ATTR4:[0-9]+]] +// CHECK-NEXT: unreachable +// CHECK: [[BB1:.*:]] +// CHECK-NEXT: [[CALL:%.*]] = call noundef zeroext i1 @_Z5checkRK1T(ptr noundef nonnull align 1 dereferenceable(1) [[REF_TMP]]) +// CHECK-NEXT: call void @_ZN1TD1Ev(ptr noundef nonnull align 1 dereferenceable(1) [[REF_TMP]]) #[[ATTR5:[0-9]+]] +// CHECK-NEXT: br i1 [[CALL]], label %[[IF_THEN1:.*]], label %[[IF_END2:.*]] +// CHECK: [[IF_THEN1]]: +// CHECK-NEXT: br label %[[LABEL]] +// CHECK: [[LABEL]]: +// CHECK-NEXT: store i32 1, ptr [[RETVAL]], align 4 +// CHECK-NEXT: br label %[[RETURN:.*]] +// CHECK: [[IF_END2]]: +// CHECK-NEXT: store i32 0, ptr [[RETVAL]], align 4 +// CHECK-NEXT: br label %[[RETURN]] +// CHECK: [[RETURN]]: +// CHECK-NEXT: [[TMP2:%.*]] = load i32, ptr [[RETVAL]], align 4 +// CHECK-NEXT: ret i32 [[TMP2]] +// +int test(bool cond) { + if (cond) + goto label; + if (die(); check(T())) { + label: + return 1; + } + return 0; +} + +// CHECK-LABEL: define dso_local noundef i32 @_Z11test_switchb( +// CHECK-SAME: i1 noundef zeroext [[COND:%.*]]) #[[ATTR0]] { +// CHECK-NEXT: [[ENTRY:.*:]] +// CHECK-NEXT: [[RETVAL:%.*]] = alloca i32, align 4 +// CHECK-NEXT: [[COND_ADDR:%.*]] = alloca i8, align 1 +// CHECK-NEXT: [[REF_TMP:%.*]] = alloca [[STRUCT_T:%.*]], align 1 +// CHECK-NEXT: [[STOREDV:%.*]] = zext i1 [[COND]] to i8 +// CHECK-NEXT: store i8 [[STOREDV]], ptr [[COND_ADDR]], align 1 +// CHECK-NEXT: [[TMP0:%.*]] = load i8, ptr [[COND_ADDR]], align 1 +// CHECK-NEXT: [[LOADEDV:%.*]] = icmp ne i8 [[TMP0]], 0 +// CHECK-NEXT: br i1 [[LOADEDV]], label %[[IF_THEN:.*]], label %[[IF_END:.*]] +// CHECK: [[IF_THEN]]: +// CHECK-NEXT: br label %[[LABEL:.*]] +// CHECK: [[IF_END]]: +// CHECK-NEXT: call void @_Z3diev() #[[ATTR4]] +// CHECK-NEXT: unreachable +// CHECK: [[BB1:.*:]] +// CHECK-NEXT: [[CALL:%.*]] = call noundef i32 @_Z4pickRK1T(ptr noundef nonnull align 1 dereferenceable(1) [[REF_TMP]]) +// CHECK-NEXT: call void @_ZN1TD1Ev(ptr noundef nonnull align 1 dereferenceable(1) [[REF_TMP]]) #[[ATTR5]] +// CHECK-NEXT: switch i32 [[CALL]], label %[[SW_EPILOG:.*]] [ +// CHECK-NEXT: i32 1, label %[[SW_BB:.*]] +// CHECK-NEXT: ] +// CHECK: [[SW_BB]]: +// CHECK-NEXT: store i32 1, ptr [[RETVAL]], align 4 +// CHECK-NEXT: br label %[[RETURN:.*]] +// CHECK: [[LABEL]]: +// CHECK-NEXT: store i32 2, ptr [[RETVAL]], align 4 +// CHECK-NEXT: br label %[[RETURN]] +// CHECK: [[SW_EPILOG]]: +// CHECK-NEXT: store i32 0, ptr [[RETVAL]], align 4 +// CHECK-NEXT: br label %[[RETURN]] +// CHECK: [[RETURN]]: +// CHECK-NEXT: [[TMP2:%.*]] = load i32, ptr [[RETVAL]], align 4 +// CHECK-NEXT: ret i32 [[TMP2]] +// +int test_switch(bool cond) { + if (cond) + goto label; + switch (die(); pick(T())) { + case 1: + return 1; + label: + return 2; + } + return 0; +} _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
