lgm@ODDJOB.UCHICAGO.EDU (11/19/88)
I have recently been trying to use the new '-fstrength-reduce' optimization on GNU CC Version 1.30, on an AT&T UNIX PC 3B1 Computer (which runs a Motorola 68010). In particular, I have been trying to get GCC to compile itself with '-fstrength-reduce' *plus* all other possible optimizations. I first ran into the problem with "genemit.c". I posted this problem several days ago. I soon was mailed a fix from Jim Wilson at 'wilson@ji.berkeley.edu', and the fix works. I eventually found two more files which were being compiled incorrectly. "reload.c" ran correctly when compiled by '-O -fomit-frame-pointer -fcombine-regs -fforce-addr -fforce-mem' but core-dumped when '-fstrength-reduce' was added to its compilation line. "cccp.c" ran correctly when compiled by '-O -fomit-frame-pointer -fcombine-regs' but core-dumped when '-fstrength-reduce' was added. (I have already posted a bug preventing me from using '-fforce-mem' or '-fforce-addr' on "cccp.c".) Unfortunately, I was unable to identify any clearly incorrect code generation for either file, even after a fairly close inspection of the assembly language differences with and without '-fstrength-reduce'. After adjusting the compilation lines for "reload.c" and "cccp.c", GCC Version 1.30 indeed correctly compiles itself with '-fstrength-reduce'. Lawrence G. Mayka Aurora, Illinois chinet!lmayk!lgm