16 Jul 11:40
Re: Is this the expected behavior?
From: Paolo Bonzini <bonzini <at> gnu.org>
Subject: Re: Is this the expected behavior?
Newsgroups: gmane.comp.gcc.devel
Date: 2008-07-16 09:40:23 GMT
Subject: Re: Is this the expected behavior?
Newsgroups: gmane.comp.gcc.devel
Date: 2008-07-16 09:40:23 GMT
Mohamed Shafi wrote: > 2008/7/15 Ramana Radhakrishnan <ramana.r <at> gmail.com>: >> <snipped parts of the last mail> >> >>> I agree with you, but what about when there are still caller save >>> register are available and there are no register restrictions for any >>> instructions? In my case i find that GCC has used only the argument >>> registers, stack pointer and callee saved registers. So out of the 16 >>> available registers ony 5+1+4 registers were used, even though there >>> was 6 caller save registers were available >> >> Check your REG_ALLOC_ORDER macro ? > > The order is argument registers, caller save registers and finally > the callee save registers. Are there instructions that only work on the callee-save registers? This might confuse regclass (the pass that decides the register class preferences). Paolo
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