[clang] [AMDGPU] Make `__GCC_DESTRUCTIVE_SIZE` 128 on AMDGPU (PR #115241)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: Joseph Huber (jhuber6)

<details>
<summary>Changes</summary>

Summary:
The cache line size on AMDGPU varies between 64 and 128 (The lowest L2
cache also goes to 256 on some architectures.) This macro is intended to
present a size that will not cause destructive interference, so we
choose the larger of those values.


---
Full diff: https://github.com/llvm/llvm-project/pull/115241.diff


1 Files Affected:

- (modified) clang/lib/Basic/Targets/AMDGPU.h (+4) 


``````````diff
diff --git a/clang/lib/Basic/Targets/AMDGPU.h b/clang/lib/Basic/Targets/AMDGPU.h
index 6edd3474d4edae..81e96ed65c47bf 100644
--- a/clang/lib/Basic/Targets/AMDGPU.h
+++ b/clang/lib/Basic/Targets/AMDGPU.h
@@ -462,6 +462,10 @@ class LLVM_LIBRARY_VISIBILITY AMDGPUTargetInfo final : public TargetInfo {
   }
 
   bool hasHIPImageSupport() const override { return HasImage; }
+
+  std::pair<unsigned, unsigned> hardwareInterferenceSizes() const override {
+    return std::make_pair(128, 128);
+  }
 };
 
 } // namespace targets

``````````

</details>


https://github.com/llvm/llvm-project/pull/115241