[SM6.10][Bugfix] Make sure DstN::Value calculation is rounded up (#8359)

Fixes #8356

Author: hekota

tools/clang/lib/Headers/hlsl/dx/linalg.h

@@ -186,8 +186,11 @@ __MATRIX_SCALAR_COMPONENT_MAPPING(ComponentType::U64, uint64_t)
 __MATRIX_SCALAR_COMPONENT_MAPPING(ComponentType::F64, double)
 
 template <ComponentEnum DstTy, ComponentEnum SrcTy, int SrcN> struct DstN {
+  // Make sure to round up in case SrcN isn't an even multiple of the number of
+  // elements per scalar
   static const int Value =
-      (SrcN * ComponentTypeTraits<SrcTy>::ElementsPerScalar) /
+      (SrcN * ComponentTypeTraits<SrcTy>::ElementsPerScalar +
+       ComponentTypeTraits<DstTy>::ElementsPerScalar - 1) /
       ComponentTypeTraits<DstTy>::ElementsPerScalar;
 };
 

tools/clang/test/CodeGenDXIL/hlsl/linalg/api/vectors.hlsl

@@ -82,4 +82,9 @@ void main(uint ID : SV_GroupID) {
   half16 srcF16 = BAB.Load<half16>(128);
   InterpretedVector<uint, 4, ComponentEnum::F8_E4M3FN> convertedPacked = Convert<ComponentEnum::F8_E4M3FN, ComponentEnum::F16>(srcF16);
 
+  // CHECK: call <1 x i32> @dx.op.linAlgConvert.v1i32.v3f16(i32 -2147483618, <3 x half> %25, i32 8, i32 21)
+  // CHECK-SAME: ; LinAlgConvert(inputVector,inputInterpretation,outputInterpretation)
+  half3 ThreeF16 = BAB.Load<half3>(256);
+  InterpretedVector<uint, 1, ComponentEnum::F8_E4M3FN> convertedPacked2 =
+      Convert<ComponentEnum::F8_E4M3FN, ComponentEnum::F16>(ThreeF16);
 }