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Re: PING: PR/17236, improve long long multiply on x86 (middle-end)
Ian Lance Taylor wrote:
Paolo Bonzini <email@example.com> writes:
I'm OK with making this sort of change without a clear argument, but
only if you're prepared to do performance testing on three or more
primary platforms. I'm not OK with making this sort of change with
neither an argument nor performance testing. Right now, as far as I
know, you just have a single test case which improves.
I already had SPEC on x86 and it was neutral, except that half of
SPECfp was perturbated by the machine load. I should be able to rerun
it sometime next week. Running i386 and x86_64 would not be very
different (the RA problems are the same -- %eax/%edx for MUL/DIV and
%cl for shift counts) and I don't have access to other platforms.
I think you do need some performance results on other platforms.
There are people who can help you get them.
IRA branch already gets the register allocation part right. I'll commit
only the parts you approved, the local-alloc.c tweak will remain on hold
until we see if IRA gets into 4.4 (as I hope).