Mail Archives: pgcc/1999/10/30/21:53:46
I did a similar post a while back comparing output by pgcc for 2.95.1
and 2.91.6. The floating point performance between the two has taken a
severe dive, but the integer/logic performance is up. The latter
accounts for 95% of generated code, I will go out on a limb and claim,
but still the large drop in floating point performance is a bummer.
This on a P2-333 system. I used the Byte-benchmark, the source code for
which is commonly available on the net.
BTW, I have the exact same experience with bladeenc as below, but on my
P6-cored P2-333. Can't use unroll-loops. I've removed it from my
global config.cache and several problems cleared up in other programs.
a
Fox wrote:
>
> Hello
>
> I have an amd k6 233, Redhat 6.0 and kernel 2.2.13,
> just 2 days ago I have installed pgcc 2.95.1 (before I used pgcc 1.1.1).
> Than I have done some test:
> 1) bladeenc
> compiling codec.c with an optimaztion higher than -O1 gives a
> a working but bad encoder (but this is known even whith older
> versions of pgcc and egcs).
> compiling the rest of it (not the codec) whith -funroll-all-loops
> makes bladeenc crash (whith pgcc 1.1.1 it didn't).
> compiling whith -ffast-math gives a slow and bad working encoder
> compiling bladeenc whithout -funroll-all-loops gives a fast
> well-working
> bladeenc (faster the one compiled with pgcc 1.1.1 with
> -funroll-all-loops
> enabled). So the flags I used for bladeenc :
> -O6 -malign-functions=2 -malign-jumps=2 -mk6 -march=k6
> 2) XFree 3.3.5
> compiling with pgcc 2.95.1 and with
> -O6 -fno-strength-reduce -malign-functions=2 -malign-jumps=2 -mk6
> -march=k6
> gives a not working X server (it crashes on startup),
> compiling whith pgcc 1.1.1 and with
> -O6 -fno-strength-reduce -malign-functions=2 -malign-jumps=2 -mamdk6
> -march=amdk6 -funroll-all-loops
> gives a very fast and perfect Xserver (I have used it for mounths
> without a crash).
> 3) Mozilla M10
> compiling with pgcc 2.95.1 and with
> -O6 -fno-strength-reduce -malign-functions=2 -malign-jumps=2 -mk6
> -march=k6
> gives a not working executable
> compiling with pgcc 1.1.1 there is no way to get the build finished
> (due
> to compiler internal errors)
> 4) WindowMaker 0.61.1
> The one compiled with pgcc 2.95.1 is much faster than the one compiled
> with
> pgcc 1.1.1.
> 5) The -fno-strength-reduce flag
> The problems that there were in pgcc 1.1.1 with the
> -fno-strength-reduce flags
> seem to be resolved in pgcc 2.95.1
>
> My Conclusions:
> I find pgcc 1.1.1 much more reliable even if a little bit slower.
>
> I hope you can tell me that I'm missing some "magic" flag that will
> make me compile Xfree and mozilla perfectly.
> If not I hope that this mail will help pgcc develop in some ways.
> Bye
> Fox
>
> P.S.
> Sorry for my bad english
> --
> -----------------------------
> Fabio Volpe
> fox AT cclinf DOT polito DOT it
> fabiovolpe AT libero DOT it
> via M. Ausiliatrice n. 32
> Torino ITALY
> Tel. 011/5224283
> ICQ. 5214579
> -----------------------------
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