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Re: gcc-2.7 creates faster code than pgcc-1.1.1
- To: "Martin v. Loewis" <martin at mira dot isdn dot cs dot tu-berlin dot de>
- Subject: Re: gcc-2.7 creates faster code than pgcc-1.1.1
- From: Jeffrey A Law <law at hurl dot cygnus dot com>
- Date: Thu, 04 Mar 1999 19:07:48 -0700
- cc: hjl at varesearch dot com, medtekh at orc dot ru, egcs at egcs dot cygnus dot com
- Reply-To: law at cygnus dot com
In message <199903050001.BAA00973@mira.isdn.cs.tu-berlin.de>you write:
> > - if ((TARGET_ZERO_EXTEND_WITH_AND || REGNO (operands[0]) == 0)
> > + if ((TARGET_ZERO_EXTEND_WITH_AND || (0 & REGNO (operands[0]) == 0))
>
> It's late, so I'm probably going to say stupid things, but ...
>
> Isn't (0 & REGNO (operands[0]) == 0) always 0? Why isn't the condition
> just deleted?
Disabling the code like that is actually the wrong thing to do for certain
processor variants.
I need to dust off my changes to this code which do the right thing when
optimizing for size, PPro, Pent and older x86 variants.
It's not as simple as just deleting the test like that.
jeff