Possible incorrect translation of OPCODE_AND

[TiemoJung]

Hi,

it looks like that for GLSL the operation OPCODE_AND may be wrong under certain circumstances.
In the case when it is turned into a mix call. The third parameter, the selector is a boolean but gets cast to an float, this seems to be wrong as the cast seems to trigger undefined behavior when feed to glslang to turn it into spir-v. it should either used directly if the target supports it (glsl 4.5?) or turned into an appropriate vector manually (or don't use mix at all).

[strandborg]

Hi, can you provide a repro hlsl shader that triggers this please?

[TiemoJung]

Hi,

it looks like that this is probably a driver problem, the resulting spir-v is valid but as it seems the driver has troupe handling a sequence of select (convert bool to float) and mix correctly.

[TiemoJung]

Either way, it would be an optimization to use the bool directly instead of casting it to float (it results in removal of the mix call if turned into spir-v as example). Not sure since which version the boolean selector is allowed, at least 4.4 allows it.