ggml-org/llama.cpp b11635

on GitHub

ggml-cpu : keep the FP16->FP32 lookup table on x86 with F16C (#30342) (#30343)

• ggml-cpu : keep the FP16->FP32 lookup table on x86 with F16C (#30342)

#30270 routed both scalar conversions through F16C. For FP16->FP32, Clang 20.1.8
lowers the intrinsic to a vpinsrw merging into the live accumulator register of
the quantized dot products, which serialises the loop (19 vs 4 cycles/iteration
estimated, 45-65% slower Q8_0/Q4_0 MUL_MAT_ID kernels measured). Keep F16C for
FP32->FP16 as intended and the table for FP16->FP32.

• ggml-cpu : comment out the F16C FP16->FP32 define instead of removing it (review)