Some stats on an aarch64 binary of my current main project (1.6MB .text, 6600 symbols as per whatever "nm the-binary | wc -l" includes, from "objdump -d the-binary"):
19546 /tbn?z/
18029 /tbn?z.*, #0x0/ (but this includes boolean checks)
224 /tbn?z.*, #0x1f/ (i.e. 32-bit x<0)
1139 /tbn?z.*, #0x3f/ (i.e. 64-bit x<0)
154 other immediates
Said project doesn't do fixed bitfields much (there are some, but a chunk of those test multiple bits) so unsurprisingly not much. (I could imagine that the kernel has significantly more, but it's an edge-case (though perhaps an important one) of being basically massive amounts of fixed configurable glue)
That is quite a good bit more evenly-spread (the "..." is 5159 instrs).
Wonder what's up with bit 21; if whatever uses it so much is repositionable (and not an aarch64-specific thing), could save like 2KB on x86-64 via putting it in the low 8 bits instead.
Some stats on an aarch64 binary of my current main project (1.6MB .text, 6600 symbols as per whatever "nm the-binary | wc -l" includes, from "objdump -d the-binary"):
Said project doesn't do fixed bitfields much (there are some, but a chunk of those test multiple bits) so unsurprisingly not much. (I could imagine that the kernel has significantly more, but it's an edge-case (though perhaps an important one) of being basically massive amounts of fixed configurable glue)
Did a quick grep over object files of a half build defconfig kernel:
That is quite a good bit more evenly-spread (the "..." is 5159 instrs).
Wonder what's up with bit 21; if whatever uses it so much is repositionable (and not an aarch64-specific thing), could save like 2KB on x86-64 via putting it in the low 8 bits instead.