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Re: optimization/7325: Test "if ( a && b )" where a, b are 1-bit fields, could be better
- From: reichelt at igpm dot rwth-aachen dot de
- To: falk at efalk dot org, gcc-bugs at gcc dot gnu dot org, gcc-prs at gcc dot gnu dot org, nobody at gcc dot gnu dot org
- Date: 14 Jan 2003 14:46:55 -0000
- Subject: Re: optimization/7325: Test "if ( a && b )" where a, b are 1-bit fields, could be better
- Reply-to: reichelt at igpm dot rwth-aachen dot de, falk at efalk dot org, gcc-bugs at gcc dot gnu dot org, gcc-prs at gcc dot gnu dot org, nobody at gcc dot gnu dot org, gcc-gnats at gcc dot gnu dot org
Synopsis: Test "if ( a && b )" where a, b are 1-bit fields, could be better
State-Changed-From-To: analyzed->closed
State-Changed-By: reichelt
State-Changed-When: Tue Jan 14 06:46:51 2003
State-Changed-Why:
There seems to be not much room for improvement, given the reply below:
> Yeah :( I had this exact same conversation with the last guy the
> bug was assigned to. I wish I'd kept my notes from then.
>
> Let's see, we were trying to determine if the test
>
> (*foo & 3) == 3
>
> could be optimized. At the time, I think we concluded that translating to
>
> (~*foo & 3) == 0
>
> which was sometimes, but usually not, an improvement.
>
> -ed falk
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7325