Re: 8/16bit oddities on avr-gcc

["Michael Kukat" <michael at unixiron dot org>]

Hi,

2007/3/2, Rupert Wood <me@rupey.net>:
> I think he wants the perftest.c.099t.optimized file that'd be generated on disk.

ah, okay, didn't use that option for now, so i didn't know that the
necessary info is written to files :) Here it comes:

;; Function test (test)

Analyzing Edge Insertions.
test ()
{
 unsigned int ivtmp.28;
 uint8_t ivtmp.27;
 uint8_t pretmp.25;
 uint8_t ctr;

<bb 0>:
 ivtmp.28 = 0;

<L0>:;
 ctr = (uint8_t) ivtmp.28;
 xx = ctr;
 ivtmp.28 = ivtmp.28 + 1;
 if (ivtmp.28 != 64) goto <L0>; else goto <L1>;

<L1>:;
 return;

}

Hm. It creates "unsigned int" for this comparison.

Now trying without the assignment within the loop:

;; Function test (test)

Analyzing Edge Insertions.
test ()
{
 uint8_t ivtmp.27;
 uint8_t pretmp.25;
 uint8_t ctr;

<bb 0>:
 ctr = 0;

<L0>:;
 __asm__ __volatile__("nop"::);
 ctr = ctr + 1;
 if (ctr != 64) goto <L0>; else goto <L1>;

<L1>:;
 return;

}

Here, ctr is taken for the comparison, not one of those ivtmp variables.

...Michael