[llvm-branch-commits] [clang] [llvm] [RISCV] Support __builtin_cpu_is (PR #116231)

[Yingwei Zheng via llvm-branch-commits]

================
@@ -22505,6 +22506,53 @@ Value *CodeGenFunction::EmitHexagonBuiltinExpr(unsigned BuiltinID,
   return nullptr;
 }
 
+Value *CodeGenFunction::EmitRISCVCpuIs(const CallExpr *E) {
+  const Expr *CPUExpr = E->getArg(0)->IgnoreParenCasts();
+  StringRef CPUStr = cast<clang::StringLiteral>(CPUExpr)->getString();
+  return EmitRISCVCpuIs(CPUStr);
+}
+
+Value *CodeGenFunction::EmitRISCVCpuIs(StringRef CPUStr) {
+  llvm::Type *Int32Ty = Builder.getInt32Ty();
+  llvm::Type *Int64Ty = Builder.getInt64Ty();
+  llvm::Type *StructTy = llvm::StructType::get(Int32Ty, Int64Ty, Int64Ty);
+  llvm::Constant *RISCVCPUModel =
+      CGM.CreateRuntimeVariable(StructTy, "__riscv_cpu_model");
+  cast<llvm::GlobalValue>(RISCVCPUModel)->setDSOLocal(true);
+
+  auto loadRISCVCPUID = [&](unsigned Index, llvm::Type *ValueTy,
+                            CGBuilderTy &Builder, CodeGenModule &CGM) {
+    llvm::Value *GEPIndices[] = {Builder.getInt32(0),
+                                 llvm::ConstantInt::get(Int32Ty, Index)};
+    Value *Ptr = Builder.CreateInBoundsGEP(StructTy, RISCVCPUModel, GEPIndices);
+    Value *CPUID = Builder.CreateAlignedLoad(
+        ValueTy, Ptr,
+        CharUnits::fromQuantity(ValueTy->getScalarSizeInBits() / 8));
----------------
dtcxzyw wrote:

```suggestion
        ValueTy, Ptr, MayBeAlign{});
```
It will be automatically set to `DL.getABITypeAlign`.


https://github.com/llvm/llvm-project/pull/116231