(Disclaimer: I have no clue about Gallium or Cell, so I may just be confused by the names of the functions.)

The emit_MAX function in cell/ppu/cell_gen_fp.c seems dubious. When s2 >= s1, it correctly returns s2. But when s2 < s1, it returns ~s1 & s2 instead of s1. There is a similar issue for emit_MIN.

As a side note, why not use the selb instruction? (See disclaimer above, perhaps there is no such instruction.)

spe_fcgt(gen->f, d_reg, s2_reg, s1_reg);
spe_selb(gen->f, d_reg, s1_reg, s2_reg, d_reg);