optimization options not working
Ian Lance Taylor
iant@google.com
Tue Feb 23 18:19:00 GMT 2010
rohitgeek <rohit23taneja@gmail.com> writes:
> 1. Created the machine description files
> 2. Build my target (successful)
> 3. Compile
> Now this step works correctly i.e. generate correct assembly if i do
> not put any optimization option.
>
> command : ---- ./target-gcc -S test.c -> works
> ./target-gcc -O1/2/3 -S test.c -> no
> assembly corresponding to the variable assignment and all other operations
> i.e. it generates only prologue and epilogue(if i am correct for later
> part).
You didn't show us test.c. You have to tell us what you did if you
expect a good answer to your question.
Without seeing test.c, I would guess that the variables are not used,
and were removed by the optimizers.
> Give me some insight into working of peephole optimizations, how do i start
> doing that.
Peephole optimization is a specific type of optimization. See
define_peephole and define_peephole2 in the internals documentation.
See many examples in the existing backends.
Ian
More information about the Gcc-help
mailing list