Re: c/8962: "-O2 -mmmx" makes gcc seg fault

["Mack Lobell" <macklobell@hotmail.com>]

The following reply was made to PR c/8962; it has been noted by GNATS.

From: "Mack Lobell" <macklobell@hotmail.com>
To: bangerth@ticam.utexas.edu
Cc: gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Subject: Re: c/8962: "-O2 -mmmx" makes gcc seg fault
Date: Sat, 21 Dec 2002 17:44:38 +0000

 Ok,
 
 more tests:
 
 downloaded 3.3 branch and 3.4 current.
 
 Results:
 
 ***** Build with 3.3 branch *****
 
 $ ~/build/gcc3.3/gcc/xgcc.exe -B ~/build/gcc3.3/gcc -c -O2 -mmmx expr.i
 /home/lobell/src/gcc-20021202/gcc/expr.c: In function `expand_expr':
 /home/lobell/src/gcc-20021202/gcc/expr.c:9306: internal compiler error: 
 Segmentation fault
 Please submit a full bug report,
 with preprocessed source if appropriate.
 See <URL:http://www.gnu.org/software/gcc/bugs.html> for instructions.
 
 lobell@VOLVO ~/gcc_test
 $ ~/build/gcc3.3/gcc/xgcc.exe -B ~/build/gcc3.3/gcc -v
 Reading specs from /home/lobell/build/gcc3.3/gcc/specs
 Configured with: /home/lobell/src/gcc3.3/gcc/configure --enable-languages=c 
 --disable-nls
 Thread model: single
 gcc version 3.3 20021221 (prerelease)
 
 
 ***** Build with 3.4 current *****
 
 lobell@VOLVO ~/gcc_test
 $ ll
 total 873
 drwxrwxrwx+   2 lobell   None            0 Dec 21 18:40 .
 drwxrwxrwx+   8 lobell   None            0 Dec 21 17:54 ..
 -rw-rw-rw-    1 lobell   None       893508 Dec 16 15:32 expr.i
 
 lobell@VOLVO ~/gcc_test
 $ ~/build/gcc_current1/gcc/xgcc.exe -B ~/build/gcc_current1/gcc -c -O2 -mmmx 
 expr.i
 
 lobell@VOLVO ~/gcc_test
 $ ll
 total 1099
 drwxrwxrwx+   2 lobell   None            0 Dec 21 18:41 .
 drwxrwxrwx+   8 lobell   None            0 Dec 21 17:54 ..
 -rw-rw-rw-    1 lobell   None       893508 Dec 16 15:32 expr.i
 -rw-rw-rw-    1 lobell   None       231308 Dec 21 18:41 expr.o
 
 lobell@VOLVO ~/gcc_test
 $ ~/build/gcc_current1/gcc/xgcc.exe -B ~/build/gcc_current1/gcc -v
 Reading specs from /home/lobell/build/gcc_current1/gcc/specs
 Configured with:
 Thread model: single
 gcc version 3.4 20021221 (experimental)
 
 
 Conclusion:
 The bug exists only in 3.3 branch.
 
 Does that help?
 
 Regards.
 
 
 
 >From: Wolfgang Bangerth <bangerth@ticam.utexas.edu>
 >To: Mack Lobell <macklobell@hotmail.com>
 >CC: gcc-bugs@gcc.gnu.org, <gcc-gnats@gcc.gnu.org>
 >Subject: Re: c/8962: "-O2 -mmmx" makes gcc seg fault
 >Date: Sat, 21 Dec 2002 10:55:13 -0600 (CST)
 >
 >
 > > did the following:
 >
 >Thanks for your experiments. I think there is no need for you to try an
 >even newer snapshot. The only thing you could do is try to strip down the
 >testcase as much as possible, presently it is rather long. We usually do
 >that by first stripping off the line number lines using
 >   perl -pi -e 's/^#.*\n//g;' expr.i
 >so that the compiler gives the _actual_ line number in this file when it
 >crashes. Then try to delete as much stuff from the file as you can.
 >Usually, one can get it down to 20-30 lines and still see the crash. But
 >be warned that this can be a tediuous process that could take 30 minutes
 >to an hour, if you're not frequently doing such things.
 >
 >Thanks for your help
 >   Wolfgang
 >
 >-------------------------------------------------------------------------
 >Wolfgang Bangerth              email:           bangerth@ticam.utexas.edu
 >                                www: http://www.ticam.utexas.edu/~bangerth
 
 
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