> Hi, > > I'm re-posting patches which I have posted at the end of stage 1 but > which have not passed review yet. > > 8<-------------------------------------------------------------------- > > Fortran descriptors are structures which are often constructed just > for a particular argument of a particular call where it is passed by > reference. When the called function is under compiler's control, it > can be beneficial to split up the descriptor and pass it in individual > parameters. Unfortunately, currently we allow IPA-SRA to replace a > pointer with a set of replacements which are at most twice as big in > total and for descriptors we'd need to bump that factor to seven. > > This patch looks for parameters which are ADDR_EXPRs of local > variables which are written to and passed as arguments by reference > but are never loaded from and marks them with a flag in the call edge > summary. The IPA analysis phase then identifies formal parameters > which are always fed such arguments and then is more lenient when it > comoes to size. > > In order not to store to maximums per formal parameter, I calculate > the more lenient one by multiplying the existing one with a new > parameter. If it is preferable to keep the maximums independent, we > can do that. Documentation for the new parameter is missing as I > still need to re-base the patch on a version which has sphinx. I will > write it before committing. > > I have disable IPA-SRA in pr48636-2.f90 in order to be able to keep > using its dump-scan expressions. The new testcase is basically a copy > of it with different options and IPA-SRA dump scans. > > Bootstrapped and tested individually when I originally posted it and > now bootstrapped and LTO-bootstrapped and tested as part of the whole > series. OK for master? > > > gcc/ChangeLog: > > 2022-11-11 Martin Jambor <mjam...@suse.cz> > > * ipa-sra.c (isra_param_desc): New field not_specially_constructed. > (struct isra_param_flow): New field constructed_for_calls. > (isra_call_summary::dump): Dump the new flag. > (loaded_decls): New variable. > (dump_isra_param_descriptor): New parameter hints, dump > not_specially_constructed if it is true. > (dump_isra_param_descriptors): New parameter hints, pass it to > dump_isra_param_descriptor. > (ipa_sra_function_summaries::duplicate): Duplicate new flag. > (create_parameter_descriptors): Adjust comment. > (get_gensum_param_desc): Bail out when decl2desc is NULL. > (scan_expr_access): Add loaded local variables to loaded_decls. > (scan_function): Survive if final_bbs is NULL. > (isra_analyze_call): Compute constructed_for_calls flag. > (process_scan_results): Be optimistic about size limits. Do not dump > computed param hints when dumpint IPA-SRA structures. > (isra_write_edge_summary): Stream constructed_for_calls. > (isra_read_edge_summary): Likewise. > (ipa_sra_dump_all_summaries): New parameter hints, pass it to > dump_isra_param_descriptor. > (flip_all_hints_pessimistic): New function. > (flip_all_param_hints_pessimistic): Likewise. > (propagate_param_hints): Likewise. > (disable_unavailable_parameters): Renamed to > adjust_parameter_descriptions. Expand size limits for parameters > which are specially contstructed by all callers. Check limits again.p > (ipa_sra_analysis): Pass required hints to ipa_sra_dump_all_summaries. > Add hint propagation. > (ipa_sra_summarize_function): Initialize and destory loaded_decls, > rearrange so that scan_function is called even when there are no > candidates. > * params.opt (ipa-sra-ptrwrap-growth-factor): New parameter.
Hmm, this is quite specific heuristics, but I do not have much better ideas, so it is OK :) Can this be useful also for inlining? Honza
