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

[Greg Roth via cfe-commits]

================
@@ -1366,6 +1383,67 @@ bool SPIRVInstructionSelector::selectRsqrt(Register ResVReg,
       .constrainAllUses(TII, TRI, RBI);
 }
 
+// Since there is no integer dot implementation, expand by piecewise multiplying
----------------
pow2clk wrote:

Those are fairly recent SPIRV extensions. I didn't think incorporating them was within scope. 

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