[llvm] [Offload] Remove check on kernel argument sizes (PR #162121)

[Joseph Huber via llvm-commits]

https://github.com/jhuber6 created https://github.com/llvm/llvm-project/pull/162121

Summary:
This check is unnecessarily restrictive and currently incorrectly fires
for any size less than eight bytes. Just remove it, we do sanity checks
elsewhere and at some point need to trust the ABI.


>From 72195f5ea1b056cbb7c40a804f5ff78f3349212b Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Mon, 6 Oct 2025 12:00:49 -0500
Subject: [PATCH] [Offload] Remove check on kernel argument sizes

Summary:
This check is unnecessarily restrictive and currently incorrectly fires
for any size less than eight bytes. Just remove it, we do sanity checks
elsewhere and at some point need to trust the ABI.
---
 offload/plugins-nextgen/amdgpu/src/rtl.cpp              | 5 -----
 offload/unittests/OffloadAPI/device_code/CMakeLists.txt | 2 ++
 offload/unittests/OffloadAPI/device_code/byte.cpp       | 3 +++
 offload/unittests/OffloadAPI/kernel/olLaunchKernel.cpp  | 1 +
 4 files changed, 6 insertions(+), 5 deletions(-)
 create mode 100644 offload/unittests/OffloadAPI/device_code/byte.cpp

diff --git a/offload/plugins-nextgen/amdgpu/src/rtl.cpp b/offload/plugins-nextgen/amdgpu/src/rtl.cpp
index f73fa0475a3a7..8d2f9755e0351 100644
--- a/offload/plugins-nextgen/amdgpu/src/rtl.cpp
+++ b/offload/plugins-nextgen/amdgpu/src/rtl.cpp
@@ -3687,11 +3687,6 @@ Error AMDGPUKernelTy::launchImpl(GenericDeviceTy &GenericDevice,
                                  KernelArgsTy &KernelArgs,
                                  KernelLaunchParamsTy LaunchParams,
                                  AsyncInfoWrapperTy &AsyncInfoWrapper) const {
-  if (ArgsSize != LaunchParams.Size &&
-      ArgsSize > LaunchParams.Size + getImplicitArgsSize())
-    return Plugin::error(ErrorCode::INVALID_ARGUMENT,
-                         "invalid kernel arguments size");
-
   AMDGPUPluginTy &AMDGPUPlugin =
       static_cast<AMDGPUPluginTy &>(GenericDevice.Plugin);
   AMDHostDeviceTy &HostDevice = AMDGPUPlugin.getHostDevice();
diff --git a/offload/unittests/OffloadAPI/device_code/CMakeLists.txt b/offload/unittests/OffloadAPI/device_code/CMakeLists.txt
index 50e430597e646..1a042e1b38315 100644
--- a/offload/unittests/OffloadAPI/device_code/CMakeLists.txt
+++ b/offload/unittests/OffloadAPI/device_code/CMakeLists.txt
@@ -2,6 +2,7 @@ add_offload_test_device_code(foo.cpp foo)
 add_offload_test_device_code(bar.cpp bar)
 # Compile with optimizations to eliminate AMDGPU implicit arguments.
 add_offload_test_device_code(noargs.cpp noargs -O3)
+add_offload_test_device_code(byte.cpp byte)
 add_offload_test_device_code(localmem.cpp localmem)
 add_offload_test_device_code(localmem_reduction.cpp localmem_reduction)
 add_offload_test_device_code(localmem_static.cpp localmem_static)
@@ -14,6 +15,7 @@ add_custom_target(offload_device_binaries DEPENDS
     foo.bin
     bar.bin
     noargs.bin
+    byte.bin
     localmem.bin
     localmem_reduction.bin
     localmem_static.bin
diff --git a/offload/unittests/OffloadAPI/device_code/byte.cpp b/offload/unittests/OffloadAPI/device_code/byte.cpp
new file mode 100644
index 0000000000000..779d120fefcaf
--- /dev/null
+++ b/offload/unittests/OffloadAPI/device_code/byte.cpp
@@ -0,0 +1,3 @@
+#include <gpuintrin.h>
+
+extern "C" __gpu_kernel void byte(unsigned char c) { (void)c; }
diff --git a/offload/unittests/OffloadAPI/kernel/olLaunchKernel.cpp b/offload/unittests/OffloadAPI/kernel/olLaunchKernel.cpp
index 1dac8c50271b5..c9eca36a4d447 100644
--- a/offload/unittests/OffloadAPI/kernel/olLaunchKernel.cpp
+++ b/offload/unittests/OffloadAPI/kernel/olLaunchKernel.cpp
@@ -55,6 +55,7 @@ struct LaunchSingleKernelTestBase : LaunchKernelTestBase {
 
 KERNEL_TEST(Foo, foo)
 KERNEL_TEST(NoArgs, noargs)
+KERNEL_TEST(Byte, byte)
 KERNEL_TEST(LocalMem, localmem)
 KERNEL_TEST(LocalMemReduction, localmem_reduction)
 KERNEL_TEST(LocalMemStatic, localmem_static)