[Bug rtl-optimization/15927] THUMB -O2: strength-reduced iteration variable ends up off by 1
danfuzz at milk dot com
gcc-bugzilla@gcc.gnu.org
Sat Jun 19 00:49:00 GMT 2004
------- Additional Comments From danfuzz at milk dot com 2004-06-19 00:49 -------
With the new file (m2.c) I tried turning off every single fine-grained "-f" option documented as being
enabled by "-Os" and still the problem persists. That is, the following compile line still causes the
compiler to spit out bad code:
$ arm-elf-gcc -W -Wall -save-temps -c m2.c -mthumb -fno-builtin -Os -fno-strength-reduce
-fno-strict-aliasing -fno-force-mem -fno-optimize-sibling-calls -fno-cse-follow-jumps
-fno-cse-skip-blocks -fno-rerun-cse-after-loop -fno-rerun-loop-opt -fno-gcse -fno-gcse-lm
-fno-gcse-sm -fno-gcse-las -fno-delete-null-pointer-checks -fno-expensive-optimizations
-fno-regmove -fno-schedule-insns -fno-schedule-insns2 -fno-sched-interblock
-fno-sched-spec -fno-caller-saves -fno-peephole2 -fno-reorder-blocks -fno-reorder-functions
-fno-strict-aliasing -fno-unit-at-a-time -fno-crossjumping
This leads me to believe the documentation (at <http://gcc.gnu.org/onlinedocs/gcc-3.4.0/gcc/
Optimize-Options.html#Optimize%20Options>) is out-of-date with respect to what options -O2 and
-Os enable.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15927
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