For C2, convert double to float cause a loss of precision,

./chaitin.cpp:221
_high_frequency_lrg = MIN2(double(OPTO_LRG_HIGH_FREQ), _cfg.get_outer_loop_frequency());

Here, _high_frequency_lrg type is float, so maybe has a loss of precision. when it be used:

./coalesce.cpp:379
if( lrg._maxfreq >= _phc.high_frequency_lrg() ) {
   ...
}

Here, lrg._maxfreq type is double, so _high_frequency_lrg will be convert double again. But now, due to the loss of precision of _high_frequency_lrg, the conditions here may be true or false.

There are two cases that I tested for SPECjvm2008 crypto.aes.
case 1:
//chaitin.cpp:221
// fcvt.s.d $f0,$f0 #double->float
d = 16.994714324523816
f = 16.9947147

//coalesce.cpp:379
// fcvt.d.s $f0,$f0 #float->double
// fcmp.sle.d $fcc2,$f0,$f1
(gdb) i r fa0
fa0 {f = 0x0, d = 0x10} {f = -1.08420217e-19, d = 16.994714736938477}
(gdb) i r fa1
fa1 {f = 0x0, d = 0x10} {f = -7.68722312e-24, d = 16.994714324523816}

case2:
//chaitin.cpp:221
// fcvt.s.d $f0,$f0
d = 16.996332681816536
f = 16.9963322

//coalesce.cpp
// fcvt.d.s $f0,$f0
// fcmp.sle.d $fcc2,$f0,$f1
(gdb) i r fa0
fa0 {f = 0x0, d = 0x10} {f = -1.08420217e-19, d = 16.996332168579102}
(gdb) i r fa1
fa1 {f = 0x0, d = 0x10} {f = -1.73570044e-14, d = 16.996332681816536}

The above two cases result in different block generation（case2 can insert new SpillCopyNodes), and resulting score on cryto.aes is fluctuate.