On 09/30/14 08:37, Jiong Wang wrote:
On 30/09/14 05:21, Jeff Law wrote:
On 09/29/14 13:24, Jiong Wang wrote:
I don't think so. from the x86-64 bootstrap, there is no regression
on the number of functions shrink-wrapped. actually speaking,
previously only single mov dest, src handled, so the disallowing
USE/CLOBBER will not disallow shrink-wrap opportunity which was
allowed previously.
This is the key, of course. shrink-wrapping is very restrictive in its
ability to sink insns. The only forms it'll currently shrink are simple
moves. Arithmetic, logicals, etc are left alone. Thus disallowing
USE/CLOBBER does not impact the x86 port in any significant way.
yes, and we could get +1.22% (2567 compared with 2536) functions
shrink-wrapped
after we sinking more insn except simple "mov dest, src" on x86-64
bootstrap. and
I remember the similar percentage on glibc build.
while on aarch64, the overall functions shrink-wrapped increased +25% on
some
programs. maybe we could gain the same on other RISC backend.
I do agree with Richard that it would be useful to see the insns that
are incorrectly sunk and the surrounding context.
So I must be missing something. I thought the shrink-wrapping code
wouldn't sink arithmetic/logical insns like we see with insn 14 and insn
182. I thought it was limited to reg-reg copies and constant
initializations.
Jeff
