Do any compilers NOT unroll loops in high optimization modes? I was under three impression this was usually unnecessary.
Comment on Hardware-Aware Coding: CPU Architecture Concepts Every Developer Should Know
pixeltree@lemmy.blahaj.zone 1 week ago
TL:DR: minimize randomness, group variables by access frequency, and unroll loops if your compiler doesn’t do that already
bejean@lemmy.world 1 week ago
pixeltree@lemmy.blahaj.zone 1 week ago
No clue, I was just frustrated with how much useless extended metaphor was in the article and thought I’d save people some time
InverseParallax@lemmy.world 1 week ago
Really depends on the target, llvm goes between unrollimg and vectorizing cleanly, to unrollimg to a ludicrous degree, to refusing to unroll period.
Some of it is subtarget specific, but sometimes it’s just weird.
Gcc is evil incarnate, all it’s passes are at war with each other, loop Canon form often broke vectorization and even unrolling period.
call_me_xale@lemmy.zip 1 week ago
tl;dr tl;dr: use a modern compiler.