`AddUint64` generating unsupported instruction for Metal

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```hlsl
StructuredBuffer In : register(t0);
RWStructuredBuffer Out : register(u1);

[numthreads(1,1,1)]
void main() {
Out[0] = AddUint64(In[0], In[0]);
uint4 Tmp = {AddUint64(In[1].xy, In[1].xy), AddUint64(In[1].zw, In[1].zw)};
Out[1] = Tmp;
uint4 Tmp2 = {AddUint64(In[2].xy, In[2].xy), AddUint64(In[2].zw, In[2].zw)};
Out[2] = Tmp2;
uint4 Tmp3 = {AddUint64(uint2(0xffffffff, 0xffffffff), uint2(1, 0)), AddUint64(uint2(1, 256), uint2(1, 256))};
Out[3] = Tmp3;
}
```
Error message:
```
/Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/llvm-project/build/bin/split-file /Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/OffloadTest/test/Feature/HLSLLib/adduint64.test /Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/llvm-project/build/tools/OffloadTest/test/clang-mtl/Feature/HLSLLib/Output/adduint64.test.tmp # RUN: at line 74
+ /Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/llvm-project/build/bin/split-file /Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/OffloadTest/test/Feature/HLSLLib/adduint64.test /Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/llvm-project/build/tools/OffloadTest/test/clang-mtl/Feature/HLSLLib/Output/adduint64.test.tmp
/Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/llvm-project/build/bin/clang-dxc -metal --dxv-path=/Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/DXC/build/bin -T cs_6_5 -Fo /Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/llvm-project/build/tools/OffloadTest/test/clang-mtl/Feature/HLSLLib/Output/adduint64.test.tmp.o /Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/llvm-project/build/tools/OffloadTest/test/clang-mtl/Feature/HLSLLib/Output/adduint64.test.tmp/source.hlsl # RUN: at line 75
+ /Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/llvm-project/build/bin/clang-dxc -metal --dxv-path=/Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/DXC/build/bin -T cs_6_5 -Fo /Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/llvm-project/build/tools/OffloadTest/test/clang-mtl/Feature/HLSLLib/Output/adduint64.test.tmp.o /Users/cbieneman/actions-runner/_work/offload-test-suite/offload-test-suite/llvm-project/build/tools/OffloadTest/test/clang-mtl/Feature/HLSLLib/Output/adduint64.test.tmp/source.hlsl
IR contains unsupported instruction: "dx.op.binaryWithCarryOrBorrow.i32".
Compilation failed
clang-dxc: error: metal-shaderconverter command failed with exit code 5 (use -v to see invocation)
```

Start with OffloadTest/test/Feature/HLSLLib/adduint64.test and reproduce the Metal configuration using the clang-dxc command shown in the report. Trace the generated dx.op.binaryWithCarryOrBorrow.i32 instruction and identify why Metal rejects it. Done means the test compiles successfully for Metal without the unsupported-instruction error.

Written by the indexing model from the issue text.