[PATCH] D35067: [x86, CGP] increase memcmp() expansion up to 4 load pairs
Joerg Sonnenberger via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 18 06:37:53 PDT 2017
joerg added a comment.
i386: code requires three push instructions + call + potential stack cleanup.
x86_64: code requires three register loads + call
memcmp expansion requires threeish instructions per unit of expansion? I'd say one unit of expansion for minsize, two for size and four for normal optimization sounds good correct? That includes a small bonus for less clobbering for size optimization. Maybe that's too pessimistic though.
https://reviews.llvm.org/D35067
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