[clang] [HLSL] generate hlsl.wavesize attribute (PR #107176)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-hlsl

Author: Xiang Li (python3kgae)

<details>
<summary>Changes</summary>

Generate function attribute hlsl.wavesize from [WaveSize].

For #<!-- -->70118

---
Full diff: https://github.com/llvm/llvm-project/pull/107176.diff


2 Files Affected:

- (modified) clang/lib/CodeGen/CGHLSLRuntime.cpp (+7) 
- (added) clang/test/CodeGenHLSL/wavesize.hlsl (+25) 


``````````diff
diff --git a/clang/lib/CodeGen/CGHLSLRuntime.cpp b/clang/lib/CodeGen/CGHLSLRuntime.cpp
index 4bd7b6ba58de0d..28ff1153c8e1e3 100644
--- a/clang/lib/CodeGen/CGHLSLRuntime.cpp
+++ b/clang/lib/CodeGen/CGHLSLRuntime.cpp
@@ -337,6 +337,13 @@ void clang::CodeGen::CGHLSLRuntime::setHLSLEntryAttributes(
                 NumThreadsAttr->getZ());
     Fn->addFnAttr(NumThreadsKindStr, NumThreadsStr);
   }
+  if (HLSLWaveSizeAttr *WaveSizeAttr = FD->getAttr<HLSLWaveSizeAttr>()) {
+    const StringRef WaveSizeKindStr = "hlsl.wavesize";
+    std::string WaveSizeStr =
+        formatv("{0},{1},{2}", WaveSizeAttr->getMin(), WaveSizeAttr->getMax(),
+                WaveSizeAttr->getPreferred());
+    Fn->addFnAttr(WaveSizeKindStr, WaveSizeStr);
+  }
 }
 
 static Value *buildVectorInput(IRBuilder<> &B, Function *F, llvm::Type *Ty) {
diff --git a/clang/test/CodeGenHLSL/wavesize.hlsl b/clang/test/CodeGenHLSL/wavesize.hlsl
new file mode 100644
index 00000000000000..ae4b2f17c543e0
--- /dev/null
+++ b/clang/test/CodeGenHLSL/wavesize.hlsl
@@ -0,0 +1,25 @@
+// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -x hlsl -triple \
+// RUN:   dxil-pc-shadermodel6.6-compute %s -DSM66 -hlsl-entry foo \
+// RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s
+
+// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -x hlsl -triple \
+// RUN:   dxil-pc-shadermodel6.8-compute %s -hlsl-entry foo \
+// RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s --check-prefix=CHECK-SM68
+
+
+// Make sure wavesize attribute get correct value for sm66 and sm68.
+// CHECK:define void @foo()
+// CHECK:"hlsl.wavesize"="8,0,0"
+
+// CHECK-SM68:define void @foo()
+// CHECK-SM68:"hlsl.wavesize"="8,128,64"
+
+[numthreads(16,8,1)]
+#ifdef SM66
+[WaveSize(8)]
+#else
+[WaveSize(8, 128, 64)]
+#endif
+void foo() {
+
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/107176