[clang] [llvm] [HLSL] Implementation of dot intrinsic (PR #81190)

[Chris B via llvm-commits]

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@@ -17895,6 +17898,52 @@ llvm::Value *CodeGenFunction::EmitScalarOrConstFoldImmArg(unsigned ICEArguments,
   return Arg;
 }
 
+Value *CodeGenFunction::EmitDXILBuiltinExpr(unsigned BuiltinID,
+                                            const CallExpr *E) {
+  switch (BuiltinID) {
+  case Builtin::BI__builtin_hlsl_dot: {
+    Value *Op0 = EmitScalarExpr(E->getArg(0));
+    Value *Op1 = EmitScalarExpr(E->getArg(1));
+    llvm::Type *T0 = Op0->getType();
+    llvm::Type *T1 = Op1->getType();
+    if (!T0->isVectorTy() && !T1->isVectorTy()) {
+      if (T0->isFloatingPointTy()) {
+        return Builder.CreateFMul(Op0, Op1, "dx.dot");
+      }
+
+      if (T0->isIntegerTy()) {
+        return Builder.CreateMul(Op0, Op1, "dx.dot");
+      }
+      ErrorUnsupported(
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llvm-beanz wrote:

If we have checking in SemaChecking for this, this error should be unreachable so it could be an assert instead.

https://github.com/llvm/llvm-project/pull/81190