bug found in Intel's ASTC compressor (part of ispc_texcomp)

I've ported Intel's ASTC compressor (in ispc_texcomp) to pure C for benchmarking and discovered this gem during the process. The swap()utility function for float values, located near the top, has a silly typo bug that casts the first value to int (!). It's used in several places on floating point values, including block errors (scores).

https://github.com/GameTechDev/ISPCTextureCompressor/blob/master/ispc_texcomp/kernel_astc.ispc#L41

How could a bug like this survive for so long? What other unfound bugs are in there?

I will be releasing the port on GitHub after more testing. I'll be checking for undefined behavior using UBSan, and also doing a statistical analysis on its ASTC output blocks to check for any issues.

I've already enhanced it to support sRGB decode vs. linear, candidate generation (instead of just best block by SSE), and I've added optional per-channel weights. For a single subset encoder (that only supports 8x8 or smaller block sizes) it looks surprisingly good - once swap() is fixed.