This is the mail archive of the gcc-bugs@gcc.gnu.org mailing list for the GCC project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

Re: [Bug target/33431] New: [SH4] performance regression between 3.4.6 and 4.x

From: Andrew STUBBS <andrew dot stubbs at st dot com>
To: gcc-bugzilla at gcc dot gnu dot org
Cc: gcc-bugs at gcc dot gnu dot org
Date: Mon, 17 Sep 2007 11:29:23 +0100
Subject: Re: [Bug target/33431] New: [SH4] performance regression between 3.4.6 and 4.x
References: <bug-33431-12348@http.gcc.gnu.org/bugzilla/>

nbkolchin at gmail dot com wrote:

Our target hardware has SH7750 processor running in little endian mode under
RTEMS. Unfortunetaly there is no way to boot linux there.

After lurking inside backend sources, I found that m4 has several variants in
GCC 4.x: m4-100, m4-200, etc. I've tried to compile this tests with m4-200
switch, but it looks like m4-200 enforces big-endian.

The 7750 has direct mapped caches and so is not the best platform for benchmarking. A slight code perturbation can give a large change in performance. :(

The m4-200 option is NOT suitable for that target. The 7750 is a 100 series core (not that that was a nomenclature that existed when it came out). As far as I know, anybody that has a 200 series or above has an official ST toolset to go with it (GCC of course).

Andrew

References:
- [Bug target/33431] New: [SH4] performance regression between 3.4.6 and 4.x
  - From: nbkolchin at gmail dot com

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]