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- From: Paul Brook <paul at codesourcery dot com>
- To: gcc at gcc dot gnu dot org
- Cc: Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>,dje at gcc dot gnu dot org
- Date: Sat, 1 Jan 2005 13:11:27 +0000
- Subject: Re: -funsafe-loop-optimizations
- Organization: CodeSourcery
- References: <20041231211409.GA22814@atrey.karlin.mff.cuni.cz>
On Friday 31 December 2004 21:14, Zdenek Dvorak wrote:
> several times some people sounded opinion that in addition to improving
> analyses in loop optimizer, we might also add a flag that would enable
> the compiler to assume that the compiled code does not contain loops
> behaving in "weird" way (loops whose control induction variables
> overflows, infinite loops with nontrivial exit conditions).
> I remember several people were against this possibility. Therefore
> I send the proposal for the patch implementing this flag first here
> to the gcc list, to give the chance to discuss about it before I try
> to test and submit it properly (or not).
Does this apply to all "loops" the compiler discovers, or just where explicit
source language looping constructs are used. If it's the former we should
IMHO document this as it's probably not obvious to many users, especially
when combined with inlining, etc.
Also, is this a property could be annotated on a per-loop basis? We know that
all compiler generated and some user generated loops satisfy these condition.