https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107640
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Martin Jambor <jamb...@gcc.gnu.org>: https://gcc.gnu.org/g:4834e9360f7bf42fbeabaa20de5619e67c9fee4e commit r13-4685-g4834e9360f7bf42fbeabaa20de5619e67c9fee4e Author: Martin Jambor <mjam...@suse.cz> Date: Wed Dec 14 00:33:05 2022 +0100 ipa: Better way of applying both IPA-CP and IPA-SRA (PR 103227) This is basically a better fix for PR 103227. The one currently in use, rushed in late at stage3, which means that IPA-CP transformation simply does a replacement of default-definition of IPA-SRA-created scalar parameters with a constant, meant that IPA-SRA actually often led to creation of a bunch of unused parameters, which was rather ironic and sub-optimal. This patch rips that old way out and makes sure the clash is resolved at clone-materialization time. What happens is that: 1) IPA-SRA IPA analysis (decision) stage recognizes the clash and does not create a param adjustment entry for such a scalar component. 2) Clone materialization code checks the IPA-CP transformation summary and when it realizes that it is removing a parameter that is a base for a discovered IPA-CP aggregate constant, and: a) the value is passed by reference, it internally records that any load of the value is replaced directly with the known constant value. IPA-SRA will not attempt to split values passed by reference when there is a write to it so we know such a load won't be on a a LHS. b) the value is passed by value, there can be stores to the corresponding bit of the aggregate and so all accesses are replaced with a new decl and an assignment of the constant to this decl is generated at the beginning of the function. The new testcase contains an xfail as the patch does not fix PR 107640 but it is one that ICEs when one is not careful about remapping indices of parameters, so I'd like to have it in testsuite/gcc.gd/ipa/ even now. I don't think that PR 107640 should be attempted through ipa-param-manipulation replacements because the information is not really there any more and we'd either need to do the replacements earlier or dig deep into the clone parent info. Instead, we should record somewhere that at the beginning of the function the bits of the global decl have known values and use that in the value numbering. That way we could one day encode also known constants in globals that do not come through parameters. gcc/ChangeLog: 2022-11-11 Martin Jambor <mjam...@suse.cz> PR ipa/103227 * ipa-param-manipulation.h (class ipa_param_adjustments): Removed member function get_updated_index_or_split. (class ipa_param_body_adjustments): New overload of register_replacement, new member function append_init_stmts, new member m_split_agg_csts_inits. * ipa-param-manipulation.cc: Include ipa-prop.h. (ipa_param_adjustments::get_updated_index_or_split): Removed. (ipa_param_body_adjustments::register_replacement): New overload, use it from the older one. (ipa_param_body_adjustments::common_initialization): Added the capability to create replacements for conflicting IPA-CP discovered constants. (ipa_param_body_adjustments::ipa_param_body_adjustments): Construct the new member. (ipa_param_body_adjustments::append_init_stmts): New function. * ipa-sra.cc: Include ipa-prop.h. (push_param_adjustments_for_index): Require IPA-CP transformation summary as a parameter, do not create replacements which are known to have constant values. (process_isra_node_results): Find and pass to the above function the IPA-CP transformation summary. * ipa-prop.cc (adjust_agg_replacement_values): Remove the functionality replacing IPA-SRA created scalar parameters with constants. Simplify, do not require parameter descriptors, do not return anything. (ipcp_transform_function): Simplify now that adjust_agg_replacement_values does not change cfg. Move definition and initialization of descriptors lower. * tree-inline.cc (tree_function_versioning): Call append_init_stmts of param_body_adjs, if there are any. gcc/testsuite/ChangeLog: 2022-11-11 Martin Jambor <mjam...@suse.cz> PR ipa/103227 PR ipa/107640 * gcc.dg/ipa/pr107640-2.c: New test.
