[clang][OpenMP] Generate pointer instead of zero element array #169723

sarnex · 2025-11-26T20:23:37Z

Some targets don't support zero element arrays, so just use a pointer instead of a zero element array of pointers if there are no captured variables.

github-actions · 2025-11-26T20:42:17Z

🐧 Linux x64 Test Results

111428 tests passed
4451 tests skipped

Signed-off-by: Nick Sarnie <nick.sarnie@intel.com>

llvmbot · 2025-11-26T22:08:27Z

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-codegen

Author: Nick Sarnie (sarnex)

Changes

Some targets don't support zero element arrays, so just use a pointer instead of a zero element array of pointers if there are no captured variables.

Patch is 66.53 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/169723.diff

6 Files Affected:

(modified) clang/lib/CodeGen/CGOpenMPRuntimeGPU.cpp (+5-2)
(modified) clang/test/OpenMP/nvptx_SPMD_codegen.cpp (+84-84)
(modified) clang/test/OpenMP/nvptx_allocate_codegen.cpp (+1-1)
(modified) clang/test/OpenMP/nvptx_multi_target_parallel_codegen.cpp (+4-4)
(modified) clang/test/OpenMP/nvptx_parallel_codegen.cpp (+8-8)
(modified) clang/test/OpenMP/nvptx_target_parallel_proc_bind_codegen.cpp (+6-6)

diff --git a/clang/lib/CodeGen/CGOpenMPRuntimeGPU.cpp b/clang/lib/CodeGen/CGOpenMPRuntimeGPU.cpp
index 572d59edb99b2..212eb3578a6b6 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntimeGPU.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntimeGPU.cpp
@@ -1258,9 +1258,12 @@ void CGOpenMPRuntimeGPU::emitParallelCall(
     // TODO: Is that needed?
     CodeGenFunction::OMPPrivateScope PrivateArgScope(CGF);
 
+    llvm::Type *CapturedVarsAddrType =
+        CapturedVars.size() ? cast<llvm::Type>(llvm::ArrayType::get(
+                                  CGM.VoidPtrTy, CapturedVars.size()))
+                            : CGM.VoidPtrTy;
     Address CapturedVarsAddrs = CGF.CreateDefaultAlignTempAlloca(
-        llvm::ArrayType::get(CGM.VoidPtrTy, CapturedVars.size()),
-        "captured_vars_addrs");
+        CapturedVarsAddrType, "captured_vars_addrs");
     // There's something to share.
     if (!CapturedVars.empty()) {
       // Prepare for parallel region. Indicate the outlined function.
diff --git a/clang/test/OpenMP/nvptx_SPMD_codegen.cpp b/clang/test/OpenMP/nvptx_SPMD_codegen.cpp
index 54f7694b55da3..422052a572fce 100644
--- a/clang/test/OpenMP/nvptx_SPMD_codegen.cpp
+++ b/clang/test/OpenMP/nvptx_SPMD_codegen.cpp
@@ -6908,7 +6908,7 @@ int a;
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    [[DOTCAPTURE_EXPR__ADDR:%.*]] = alloca i64, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    store i64 [[DOTCAPTURE_EXPR_]], ptr [[DOTCAPTURE_EXPR__ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l160_kernel_environment, ptr [[DYN_PTR]])
@@ -7007,7 +7007,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l163_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -7085,7 +7085,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l166_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -7180,7 +7180,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l169_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -7255,7 +7255,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l172_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -7330,7 +7330,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l175_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -7405,7 +7405,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l178_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -7481,7 +7481,7 @@ int a;
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    [[DOTCAPTURE_EXPR__ADDR:%.*]] = alloca i64, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    store i64 [[DOTCAPTURE_EXPR_]], ptr [[DOTCAPTURE_EXPR__ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l181_kernel_environment, ptr [[DYN_PTR]])
@@ -7588,7 +7588,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l185_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -7674,7 +7674,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l189_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -7777,7 +7777,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l193_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -7860,7 +7860,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l197_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -7943,7 +7943,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l201_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8026,7 +8026,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l205_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8109,7 +8109,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR10:[0-9]+]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l209_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8193,7 +8193,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR10]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l214_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8279,7 +8279,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR10]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l219_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8382,7 +8382,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR10]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l224_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8465,7 +8465,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR10]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l229_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8548,7 +8548,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR10]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l234_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8631,7 +8631,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR10]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l239_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8714,7 +8714,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l244_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8809,7 +8809,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l248_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8887,7 +8887,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l252_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -8982,7 +8982,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l256_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -9057,7 +9057,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l260_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -9132,7 +9132,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l264_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -9207,7 +9207,7 @@ int a;
 // CHECK-64-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-64-NEXT:  entry:
 // CHECK-64-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 8
+// CHECK-64-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 8
 // CHECK-64-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 8
 // CHECK-64-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l268_kernel_environment, ptr [[DYN_PTR]])
 // CHECK-64-NEXT:    [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
@@ -15757,7 +15757,7 @@ int a;
 // CHECK-32-NEXT:  entry:
 // CHECK-32-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 4
 // CHECK-32-NEXT:    [[DOTCAPTURE_EXPR__ADDR:%.*]] = alloca i32, align 4
-// CHECK-32-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 4
+// CHECK-32-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca ptr, align 4
 // CHECK-32-NEXT:    store ptr [[DYN_PTR]], ptr [[DYN_PTR_ADDR]], align 4
 // CHECK-32-NEXT:    store i32 [[DOTCAPTURE_EXPR_]], ptr [[DOTCAPTURE_EXPR__ADDR]], align 4
 // CHECK-32-NEXT:    [[TMP0:%.*]] = call i32 @__kmpc_target_init(ptr @{{__omp_offloading_[0-9a-z]+_[0-9a-z]+}}__Z3foov_l160_kernel_environment, ptr [[DYN_PTR]])
@@ -15856,7 +15856,7 @@ int a;
 // CHECK-32-SAME: (ptr noalias noundef [[DYN_PTR:%.*]]) #[[ATTR8]] {
 // CHECK-32-NEXT:  entry:
 // CHECK-32-NEXT:    [[DYN_PTR_ADDR:%.*]] = alloca ptr, align 4
-// CHECK-32-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = alloca [0 x ptr], align 4
+// CHECK-32-NEXT:    [[CAPTURED_VARS_ADDRS:%.*]] = a...
[truncated]

jhuber6

How difficult would it be to support a zero element array? Seems like this should be handled by the backend since it's legal LLVM-IR

arsenm · 2025-11-26T23:06:51Z

Yes, fix backends instead of working around it

shiltian · 2025-11-27T03:48:44Z

IIRC zero-element array has special semantics in OpenMP.

sarnex · 2025-12-01T15:00:27Z

Ok thanks, I'll open a bug for the backend

[clang][OpenMP] Generate pointer instead of zero element array

1211583

Signed-off-by: Nick Sarnie <nick.sarnie@intel.com>

sarnex force-pushed the emptyarr branch from 8ca3936 to 1211583 Compare November 26, 2025 21:20

sarnex marked this pull request as ready for review November 26, 2025 22:07

llvmbot added clang Clang issues not falling into any other category clang:codegen IR generation bugs: mangling, exceptions, etc. clang:openmp OpenMP related changes to Clang labels Nov 26, 2025

sarnex requested review from jhuber6, shiltian and tblah November 26, 2025 22:08

jhuber6 reviewed Nov 26, 2025

View reviewed changes

jhuber6 requested a review from arsenm November 26, 2025 22:45

sarnex closed this Dec 1, 2025

sarnex mentioned this pull request Dec 1, 2025

SPIR-V cannot handle zero element arrays #170150

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[clang][OpenMP] Generate pointer instead of zero element array #169723

[clang][OpenMP] Generate pointer instead of zero element array #169723

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