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Re: [avr-gcc-list] testsuite saga continues


From: Dave N6NZ
Subject: Re: [avr-gcc-list] testsuite saga continues
Date: Wed, 30 Jan 2008 10:17:13 -0800
User-agent: Thunderbird 1.5 (X11/20051201)



Wouter van Gulik wrote:

Yes this is exactly what I wanted to point out. The carry is now only used in handwritten assembler (in avr.md). GCC's RTL does not know anything about the carry bit being available when it's set/cleared and when it's clobbered.

Is there some limitation in the RTL that keeps one from describing condition code bits as "registers" and describing when the are set and used in the RTL? (He asks naively, never having looked at gcc's rtl...)

Wouldn't that be transparent to normal code, since the cc's would be mostly unused, and data flow analysis should discard the result in most cases... except when you want to pick them up.

-dave (sits quietly waiting for the clue-bat to descend...)





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