Set MaxAtomicInlineWidth the same way as SPIR-V targets in3cfd0c0. This PR fixes build warning in scoped atomic built-in in#146814:warning: large atomic operation may incur significant performance penalty; the access size (2 bytes) exceeds the max lock-free size (0 bytes) [-Watomic-alignment]

[SPIR] Set MaxAtomicInlineWidth minimum size to 32 for spir32 and 64 …

beb75c7

…for spir64Set MaxAtomicInlineWidth the same way as SPIR-V targets in3cfd0c0.This PR fixes build warning in scoped atomic built-in inllvm#146814:`warning: large atomic operation may incur significant performance penalty`

llvmbot added clang

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Jul 16, 2025

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llvmbot commentedJul 16, 2025

@llvm/pr-subscribers-clang

Author: Wenju He (wenju-he)

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Set MaxAtomicInlineWidth the same way as SPIR-V targets in3cfd0c0. This PR fixes build warning in scoped atomic built-in in #146814:warning: large atomic operation may incur significant performance penalty

Full diff:https://github.com/llvm/llvm-project/pull/148997.diff

2 Files Affected:

(modified) clang/lib/Basic/Targets/SPIR.h (+6)
(added) clang/test/CodeGenOpenCL/scoped-atomic.cl (+18)

diff --git a/clang/lib/Basic/Targets/SPIR.h b/clang/lib/Basic/Targets/SPIR.hindex 1abf798d93129..c13b286cd7916 100644--- a/clang/lib/Basic/Targets/SPIR.h+++ b/clang/lib/Basic/Targets/SPIR.h@@ -264,6 +264,9 @@ class LLVM_LIBRARY_VISIBILITY SPIR32TargetInfo : public SPIRTargetInfo {     PointerWidth = PointerAlign = 32;     SizeType = TargetInfo::UnsignedInt;     PtrDiffType = IntPtrType = TargetInfo::SignedInt;+    // SPIR32 has support for atomic ops if atomic extension is enabled.+    // Take the maximum because it's possible the Host supports wider types.+    MaxAtomicInlineWidth = std::max<unsigned char>(MaxAtomicInlineWidth, 32);     resetDataLayout("e-p:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-"                     "v96:128-v192:256-v256:256-v512:512-v1024:1024-G1");   }@@ -281,6 +284,9 @@ class LLVM_LIBRARY_VISIBILITY SPIR64TargetInfo : public SPIRTargetInfo {     PointerWidth = PointerAlign = 64;     SizeType = TargetInfo::UnsignedLong;     PtrDiffType = IntPtrType = TargetInfo::SignedLong;+    // SPIR64 has support for atomic ops if atomic extension is enabled.+    // Take the maximum because it's possible the Host supports wider types.+    MaxAtomicInlineWidth = std::max<unsigned char>(MaxAtomicInlineWidth, 64);     resetDataLayout("e-i64:64-v16:16-v24:32-v32:32-v48:64-"                     "v96:128-v192:256-v256:256-v512:512-v1024:1024-G1");   }diff --git a/clang/test/CodeGenOpenCL/scoped-atomic.cl b/clang/test/CodeGenOpenCL/scoped-atomic.clnew file mode 100644index 0000000000000..ec7e936684a3a--- /dev/null+++ b/clang/test/CodeGenOpenCL/scoped-atomic.cl@@ -0,0 +1,18 @@+// RUN: %clang_cc1 %s -cl-std=CL2.0 -emit-llvm -o - -triple spir-unknown-unknown -verify+// RUN: %clang_cc1 %s -cl-std=CL2.0 -emit-llvm -o - -triple spir64-unknown-unknown -verify++// expected-no-diagnostics++int fi1a(int *i) {+  int v;+  __scoped_atomic_load(i, &v, __ATOMIC_RELAXED, __MEMORY_SCOPE_DEVICE);+  return v;+}++#ifdef __SPIR64__+long fl1a(long *i) {+  long v;+  __scoped_atomic_load(i, &v, __ATOMIC_RELAXED, __MEMORY_SCOPE_DEVICE);+  return v;+}+#endif