https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
--- Comment #55 from Alexandre Oliva <aoliva at gcc dot gnu.org> --- Author: aoliva Date: Sun Sep 27 09:02:00 2015 New Revision: 228175 URL: https://gcc.gnu.org/viewcvs?rev=228175&root=gcc&view=rev Log: revert to assign_parms assignments using default defs Revert the fragile and complicated changes to assign_parms designed to enable it to use RTL assigments chosen by cfgexpand, and instead have cfgexpand use the RTL assignments by assign_parms, keying them off of the default defs that are now necessarily introduced for each parm and result. The possible lack of a default def was already a problem, and the fallbacks in place were not enough, as shown by PR67312. We now have checking asserts in set_rtl that verify that we're assigning to each var a piece of RTL that matches the expectations set forth by use_register_for_decl. for gcc/ChangeLog PR rtl-optimization/64164 PR tree-optimization/67312 PR middle-end/67340 PR middle-end/67490 PR bootstrap/67597 * cfgexpand.c (parm_in_stack_slot_p): Remove. (ssa_default_def_partition): Remove. (get_rtl_for_parm_ssa_default_def): Remove. (set_rtl): Check that RTL assignments match expectations. Loop on SUBREGs, CONCATs and PARALLELs subexprs. Set only the default def location for params and results. Record SSA names or types in REG and MEM attrs, respectively. (set_parm_rtl): New. (expand_one_ssa_partition): Drop logic that assigned MEMs with unassigned addresses. (adjust_one_expanded_partition_var): Don't accept NULL RTL on deferred stack alloc vars. (expand_used_vars): Skip partitions holding parm default defs. Move adjust_one_expanded_partition_var loop... (pass_expand::execute): ... here. Drop redundant assert. Adjust comments before the final loop over all ssa names. Require assigned rtl of parms and results to match exactly. Reset its attributes to match them, not any other variables in the same partition. (expand_debug_expr): Use entry value for PARM's default defs only iff they have zero nondebug uses. * cfgexpand.h (parm_in_stack_slot_p): Remove. (get_rtl_for_parm_ssa_default_def): Remove. (set_parm_rtl): Declare. * doc/invoke.texi: Improve wording. * explow.c (promote_decl_mode): Fix promote_function_mode for result decls not by reference. (promote_ssa_mode): Disregard BLKmode from promote_decl, and bypass TYPE_MODE to get the actual vector mode. * function.c: Include tree-dfa.h. Revert 2015-08-14's and 2015-08-19's changes as follows. Drop include of basic-block.h and df.h. (rtl_for_parm): Remove. (maybe_reset_rtl_for_parm): Remove. (parm_in_unassigned_mem_p): Remove. (use_register_for_decl): Add logic for RESULT_DECLs matching assign_parms' behavior. (split_complex_args): Revert. (assign_parms_augmented_arg_list): Revert. Add comment referencing the logic above. (assign_parm_adjust_stack_rtl): Revert. (assign_parm_setup_block): Revert. Use set_parm_rtl instead of SET_DECL_RTL. Set up a REG if the parm demands so. (assign_parm_setup_reg): Revert. Consolidated SET_DECL_RTL calls into a single set_parm_rtl. Set up a temporary RTL temporarily for expand_assignment. (assign_parm_setup_stack): Revert. Use set_parm_rtl. (assign_parms_unsplit_complex): Revert. Use set_parm_rtl. (assign_bounds): Revert. (assign_parms): Revert. Use set_parm_rtl. (allocate_struct_function): Relayout result and parms of non-abstruct functions. (expand_function_start): Revert. Use set_parm_rtl. If the result is not a hard reg, create a pseudo from the promoted mode of the default def. Promote static chain mode. * tree-outof-ssa.c (remove_ssa_form): Drop unused partition_has_default_def. Set up partitions_for_parm_default_defs. (finish_out_of_ssa): Remove partition_has_default_def. Release partitions_for_parm_default_defs. * tree-outof-ssa.h (struct ssaexpand): Remove partition_has_default_def. Add partitions_for_parm_default_defs. * tree-ssa-coalesce.c: Include tree-dfa.h, tm_p.h and stor-layout.h. (build_ssa_conflict_graph): Fix conflict-detection of default defs of even unused default defs of params and results. (for_all_parms): New. (create_default_def): New. (register_default_def): New. (coalesce_with_default): New. (create_outofssa_var_map): Create default defs for all parms and results, and register their partitions. Add GIMPLE_RETURN operands as coalesce candidates with results. Add default defs of each parm or result as coalesce candidates with its other defs. Mark each result def, and each default def of parms, as used_in_copy. (gimple_can_coalesce_p): Call it. Call use_register_for_decl with the ssa names, even anonymous ones. Drop parm_in_stack_slot_p calls. Require same signedness and alignment. (coalesce_ssa_name): Add coalesce candidates for all defs of each parm and result, even unused ones. (parm_default_def_partition_arg): New type. (set_parm_default_def_partition): New. (get_parm_default_def_partitions): New. * tree-ssa-coalesce.h (get_parm_default_def_partitions): New. * tree-ssa-live.c (partition_view_init): Regard unused defs of parms and results as used. (verify_live_on_entry): Don't error out just because they're not live. for gcc/testsuite/ChangeLog PR rtl-optimization/64164 PR tree-optimization/67312 * gcc.dg/pr67312.c: New. From Zdenek Sojka. * gcc.target/i386/stackalign/return-4.c: Add -O. Added: trunk/gcc/testsuite/gcc.dg/pr67312.c Modified: trunk/gcc/ChangeLog trunk/gcc/cfgexpand.c trunk/gcc/cfgexpand.h trunk/gcc/doc/invoke.texi trunk/gcc/explow.c trunk/gcc/function.c trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/gcc.target/i386/stackalign/return-4.c trunk/gcc/tree-outof-ssa.c trunk/gcc/tree-outof-ssa.h trunk/gcc/tree-ssa-coalesce.c trunk/gcc/tree-ssa-coalesce.h trunk/gcc/tree-ssa-live.c