template eqabs(a, b): bool = a * a == b * b
proc t(x: int32): bool = eqabs(x, 5) or eqabs(x, 9)
echo t(10)
nim -d:release c x. Assembly with gcc -S -fverbose-asm shows:
# /home/d067158/nimcache/x.c:50: T1_ = ((NI32)(x * x) == ((NI32) 25));
imull %edi, %edi # x, _1
movl $1, %eax #, <retval>
# /home/d067158/nimcache/x.c:51: if (T1_) goto LA2_;
cmpl $25, %edi #, _1
je .L3 #,
# /home/d067158/nimcache/x.c:52: T1_ = ((NI32)(x * x) == ((NI32) 81));
cmpl $81, %edi #, _1
sete %al #, <retval>
.L3:
# /home/d067158/nimcache/x.c:56: }
ret
Which looks fine. So if you want to depend on compiler optimizations, check the
assembly output. If you don't want that, do the optimization manually.
