[clang] [OpenCL] Fix an infinite loop in builidng AddrSpaceQualType (PR #92612)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Changpeng Fang (changpeng)

<details>
<summary>Changes</summary>

 In building AddrSpaceQualType (https://github.com/llvm/llvm-project/pull/90048), there is a bug in removeAddrSpaceQualType() for arrays. Arrays are weird because qualifiers on the element type also count as qualifiers on the type, so getSingleStepDesugaredType() can't remove the sugar on arrays. This results in an infinite loop in removeAddrSpaceQualType. To fix the issue, we use ASTContext::getUnqualifiedArrayType instead, which strips the qualifier off the element type, then reconstruct the array type.

---
Full diff: https://github.com/llvm/llvm-project/pull/92612.diff


2 Files Affected:

- (modified) clang/lib/CodeGen/CGExprAgg.cpp (+2-1) 
- (added) clang/test/CodeGenOpenCLCXX/array-type-infinite-loop.clcpp (+25) 


``````````diff
diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 6172eb9cdc1bb..53ce133e8cbc6 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -537,8 +537,9 @@ void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
       elementType.isTriviallyCopyableType(CGF.getContext())) {
     CodeGen::CodeGenModule &CGM = CGF.CGM;
     ConstantEmitter Emitter(CGF);
+    Qualifiers Quals;
     QualType GVArrayQTy = CGM.getContext().getAddrSpaceQualType(
-        CGM.getContext().removeAddrSpaceQualType(ArrayQTy),
+        CGM.getContext().getUnqualifiedArrayType(ArrayQTy, Quals),
         CGM.GetGlobalConstantAddressSpace());
     LangAS AS = GVArrayQTy.getAddressSpace();
     if (llvm::Constant *C =
diff --git a/clang/test/CodeGenOpenCLCXX/array-type-infinite-loop.clcpp b/clang/test/CodeGenOpenCLCXX/array-type-infinite-loop.clcpp
new file mode 100644
index 0000000000000..5a5b104e892f7
--- /dev/null
+++ b/clang/test/CodeGenOpenCLCXX/array-type-infinite-loop.clcpp
@@ -0,0 +1,25 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 4
+//RUN: %clang_cc1 %s -emit-llvm -O1 -o - | FileCheck %s
+
+// CHECK-LABEL: define dso_local spir_kernel void @test(
+// CHECK-SAME: ptr nocapture noundef readonly align 8 [[IN:%.*]], ptr nocapture noundef writeonly align 8 [[OUT:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] !kernel_arg_addr_space [[META3:![0-9]+]] !kernel_arg_access_qual [[META4:![0-9]+]] !kernel_arg_type [[META5:![0-9]+]] !kernel_arg_base_type [[META5]] !kernel_arg_type_qual [[META6:![0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, ptr [[IN]], i64 8
+// CHECK-NEXT:    [[TMP0:%.*]] = load i64, ptr [[ARRAYIDX1]], align 8, !tbaa [[TBAA7:![0-9]+]]
+// CHECK-NEXT:    store i64 [[TMP0]], ptr [[OUT]], align 8, !tbaa [[TBAA7]]
+// CHECK-NEXT:    ret void
+//
+__kernel void test(__global long *In, __global long *Out) {
+   long m[4] = {  In[0], In[1], 0, 0 };
+   *Out = m[1];
+}
+//.
+// CHECK: [[META3]] = !{i32 1, i32 1}
+// CHECK: [[META4]] = !{!"none", !"none"}
+// CHECK: [[META5]] = !{!"long*", !"long*"}
+// CHECK: [[META6]] = !{!"", !""}
+// CHECK: [[TBAA7]] = !{[[META8:![0-9]+]], [[META8]], i64 0}
+// CHECK: [[META8]] = !{!"long", [[META9:![0-9]+]], i64 0}
+// CHECK: [[META9]] = !{!"omnipotent char", [[META10:![0-9]+]], i64 0}
+// CHECK: [[META10]] = !{!"Simple C++ TBAA"}
+//.

``````````

</details>


https://github.com/llvm/llvm-project/pull/92612