[clang] [llvm] [HLSL][DXIL][SPIRV] Create llvm dot intrinsic and use for HLSL (PR #102872)

[Thorsten Schütt via cfe-commits]

================
@@ -303,6 +303,14 @@ SPIRVLegalizerInfo::SPIRVLegalizerInfo(const SPIRVSubtarget &ST) {
   getActionDefinitionsBuilder(G_FPOWI).legalForCartesianProduct(
       allFloatScalarsAndVectors, allIntScalarsAndVectors);
 
+  getActionDefinitionsBuilder(G_FDOTPROD)
+      .legalForCartesianProduct(allFloatScalarsAndVectors,
----------------
tschuett wrote:

```
getActionDefinitionBuilder(G_FDOTPROD)
  .legalFor({{s32, s32vector}, {s64, s64vector}, ....});
```

https://github.com/llvm/llvm-project/pull/102872