Assert when using spirv_literal parameter in spirv_instruction with set

[rdb]

Using spirv_instruction(set=) (from GL_EXT_spirv_intrinsics) with a spirv_literal parameter results in an assertion error, whereas the spec doesn't specifically forbid this combination. I first thought this was a spec oversight and that only ids were allowed, but according to extension author @Tobski (see KhronosGroup/GLSL#330) it is intended to be allowed.

#version 450

#extension GL_EXT_spirv_intrinsics : enable

spirv_instruction(set = "GLSL.std.450", id = 1)
vec4 testExtInst(vec4 x, spirv_literal int lit);

layout(location = 0) in vec4 vecIn;
layout(location = 1) out vec4 vecOut;

void main()
{
    vecOut = testExtInst(vecIn, 1);
}

Run:

glslang -V --target-env vulkan1.0 test.vert

Result:

glslang: SPIRV/spvIR.h:110: void spv::Instruction::addIdOperand(spv::Id): Assertion `id' failed.
Aborted (core dumped)

[Tobski]

Yea there's stuff like https://registry.khronos.org/SPIR-V/specs/unified1/OpenCL.ExtendedInstructionSet.100.html#vloadn which takes a literal. It's definitely supposed to be allowed, just something we missed apparently. I'll double check the grammar in the spec and see if that needs fixing or if it's a pure glslang bug.

[rdb]

From what I could tell, there's no specific restriction on this in the spec, so it's probably just an oversight in the implementation.