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Re: How can I generate a new function at compile time?


On Tue, May 27, 2014 at 5:03 PM, Benedikt Huber
<benedikt.huber@theobroma-systems.com> wrote:
> (Sorry for the duplicate.)
>
> I managed to pass the needed parameters to the generated function.
> However I cannot pin down the reason why the compilation fails.
> It seems that the cfg is somehow broken, but I cannot tell how.
> Do you have any debugging hints?
>
> As far as I can tell, the cfg is changed during the generation of the preheader
> (I do this to find the entry block easily.)
> and in the function move_sese_region_to_fn.
>
> I noticed that after pass 058t.copyrename2 the original function bar disappears
> and the new function is replaced by _GLOBAL__N_bar.constprop, could this have
> anything to do with the problem?

Unlikely.  You can disable that by using -fno-ipa-cp.

> The pass runs just after the construction of cfg,  outline.c.011t.cfg.
>
> /home/bhuber/sandbox/install/bin/gcc -O3 -I /home/bhuber/sandbox/src -c -fdump-tree-all-details -fdump-ipa-all-details -fdump-rtl-all-details -funinline-innermost-loops -Wall -Wextra /home/bhuber/sandbox/try/outline.c
> /home/bhuber/sandbox/try/outline.c: In function '_GLOBAL__N_bar.constprop':
> /home/bhuber/sandbox/try/outline.c:3:1: internal compiler error: in purge_dead_edges, at cfgrtl.c:3183

the line doesn't match anything that would ICE on current trunk, but I suppose
it's the single_succ_p assert that triggers?

Either you really got until RTL generation or somehow cfgrtl cfg hooks are
still active while you are working in your pass.

Richard.

> bar (int s, int r, unsigned * t, int * k, int * p, int * l)
> ^
> 0x67e7c4 purge_dead_edges(basic_block_def*)
>        ../../src/gcc/cfgrtl.c:3183
> 0xe5a0d6 find_bb_boundaries
>        ../../src/gcc/cfgbuild.c:522
> 0xe5a0d6 find_many_sub_basic_blocks(simple_bitmap_def*)
>        ../../src/gcc/cfgbuild.c:604
> 0x66c0f5 execute
>        ../../src/gcc/cfgexpand.c:5873
> Please submit a full bug report,
> with preprocessed source if appropriate.
> Please include the complete backtrace with any bug report.
> See <http://gcc.gnu.org/bugs.html> for instructions.
>
> I attach the transformation pass and the small example program.
>
> Thank you again for the help,
> Benedikt
>
> P.s. I am aware that this transformation is not safe in general,
>     however in this case it should work.


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