OpBit instructions that require BitInstructions capability from spec is missing

[darkyellow]

OpBitFieldSExtract is an example instruction, that according to the spec

"opname" : "OpBitFieldSExtract",
"class" : "Bit",
"opcode" : 202,
"operands" : [
{ "kind" : "IdResultType" },
{ "kind" : "IdResult" },
{ "kind" : "IdRef", "name" : "Base" },
{ "kind" : "IdRef", "name" : "Offset" },
{ "kind" : "IdRef", "name" : "Count" }
],
"capabilities" : [ "Shader", "BitInstructions" ],
"version": "1.0"

Requires the BitInstructions capability. This is not present when compiling using glslangValidator, also spirv-val does not raise an issue either

Is this a problem with the spec or is this capability really required in the generated spirv?

[arcady-lunarg]

I think the spec is pretty clear that the capability is in fact required and this is just an implementation oversight in glslang that we should fix. Feel free to file an issue against spirv-val for validating this.

[darkyellow]

I raised an issue in the spirv-tools (which was later moved to the registry). In the example I gave the capabilities were an OR not an AND so there is indeed no issues

KhronosGroup/SPIRV-Registry#383 (comment)

They are however going to update the spec to make it more clear how to interpret the spec correctly.

With all the above I would probably close this issue and not raise it as a bug.

[arcady-lunarg]

Closing as not a bug.