[Bug target/27827] gcc 4 produces worse x87 code on all platforms than gcc 3

[whaley at cs dot utsa dot edu]

------- Comment #6 from whaley at cs dot utsa dot edu  2006-05-31 01:09 -------
Subject: Re:  gcc 4 produces worse x87 code on all platforms than gcc 3

Yes, I agree it is an x86/x86_64 issue.  I have not yet scoped the performance
of any of the other architectures with gcc 4 vs. 3: since 90% of my users use
an x86 of some sort, I can't switch to gcc 4 support until the x86 performance
is reasonable.  It seems the x87 performance always goes down with any big gcc
change (bugzilla 4991 is a similar performance drop between 2.x and 3.0, though
the issues are not the exact same), probably because its oddball 2-op assembler
/ x87 stack doesn't map well to the more sane ISAs, which all compiler guys
strongly prefer :)

Thanks,
Clint


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27827