Hi all,
I'm trying to enable gcc 4.3.2 on Ubuntu to compile C code with
support of conditional moves. (and Conditional Moves as the only
enabled optimization)
I can see CMOVxx in the assembly compiled with "-O" option. However,
no CMOVxx is found in the assembly generated with just
"-fif-conversion" option.
More surprisingly (well, at least to me), I listed all the enabled
optimization options of "-O", and put them in one line. Then I
compiled the same code as:
gcc -S -falign-loops -fargument-alias
-fasynchronous-unwind-tables -fbranch-count-reg -fcommon
-fcprop-registers -fdce
-fdefer-pop -fdse
-fearly-inlining -fgcse-lm
-fguess-branch-probability -fif-conversion
-fif-conversion2 -finline-functions-called-once
-fipa-pure-const -fipa-reference -fivopts
-fjump-tables -fmerge-constants
-fmove-loop-invariants -fomit-frame-pointer
-fpeephole -frename-registers
-frerun-cse-after-loop -fsched-interblock
-fsched-spec -fsched-stalled-insns-dep
-fsigned-zeros -fsplit-ivs-in-unroller
-fsplit-wide-types -ftoplevel-reorder
-ftrapping-math -ftree-ccp -ftree-ch
-ftree-copy-prop -ftree-copyrename
-ftree-cselim -ftree-dce
-ftree-dominator-opts -ftree-dse -ftree-fre
-ftree-loop-im -ftree-loop-ivcanon
-ftree-loop-optimize -ftree-reassoc
-ftree-salias -ftree-scev-cprop
-ftree-sink -ftree-sra -ftree-ter
-ftree-vect-loop-version -funit-at-a-time
-fvar-tracking -fvect-cost-model
-fweb -o test.s test.c
And there is still no conditional moves in the assembly. I assume the
list of options would be equivalent to -O.
Please advise what you think of this problem.
My guess is that the order of the optimization options may be making
the difference.
Thank you very much!
LC
--
Best regards,
Lingchuan Meng
