https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105554
--- Comment #21 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:24c06560a7fa39049911eeb8777325d112e0deb9 commit r13-6739-g24c06560a7fa39049911eeb8777325d112e0deb9 Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Mar 17 18:59:56 2023 +0100 tree-inline: Fix up multiversioning with vector arguments [PR105554] The following testcase ICEs, because we call tree_function_versioning from old_decl which has target attributes not supporting V4DImode and so DECL_MODE of DECL_ARGUMENTS is BLKmode, while new_decl supports those. tree_function_versioning initially copies DECL_RESULT and DECL_ARGUMENTS from old_decl to new_decl, then calls initialize_cfun to create cfun and only when the cfun is created it can later actually remap_decl DECL_RESULT and DECL_ARGUMENTS etc. The problem is that initialize_cfun -> push_struct_function -> allocate_struct_function calls relayout_decl on DECL_RESULT and DECL_ARGUMENTS, which clobbers DECL_MODE of old_decl and we then ICE because of it. In particular, allocate_struct_function does: if (!abstract_p) { /* Now that we have activated any function-specific attributes that might affect layout, particularly vector modes, relayout each of the parameters and the result. */ relayout_decl (result); for (tree parm = DECL_ARGUMENTS (fndecl); parm; parm = DECL_CHAIN (parm)) relayout_decl (parm); /* Similarly relayout the function decl. */ targetm.target_option.relayout_function (fndecl); } if (!abstract_p && aggregate_value_p (result, fndecl)) { #ifdef PCC_STATIC_STRUCT_RETURN cfun->returns_pcc_struct = 1; #endif cfun->returns_struct = 1; } Now, in the case of tree_function_versioning, I believe all that we need from these is possibly the targetm.target_option.relayout_function (fndecl); call (arm only), we will remap DECL_RESULT and DECL_ARGUMENTS later on and copy_decl_for_dup_finish in that case will handle all we need: /* For vector typed decls make sure to update DECL_MODE according to the new function context. */ if (VECTOR_TYPE_P (TREE_TYPE (copy))) SET_DECL_MODE (copy, TYPE_MODE (TREE_TYPE (copy))); We don't need the cfun->returns_*struct either, because we override it in initialize_cfun a few lines later: /* Copy items we preserve during cloning. */ ... cfun->returns_struct = src_cfun->returns_struct; cfun->returns_pcc_struct = src_cfun->returns_pcc_struct; So, to avoid the clobbering of DECL_RESULT/DECL_ARGUMENTS of old_decl, the following patch arranges allocate_struct_function to be called with abstract_p true and calls targetm.target_option.relayout_function (fndecl); by hand. The removal of DECL_RESULT/DECL_ARGUMENTS copying at the start of initialize_cfun is removed because the only caller - tree_function_versioning, does that unconditionally before. 2023-03-17 Jakub Jelinek <ja...@redhat.com> PR target/105554 * function.h (push_struct_function): Add ABSTRACT_P argument defaulted to false. * function.cc (push_struct_function): Add ABSTRACT_P argument, pass it to allocate_struct_function instead of false. * tree-inline.cc (initialize_cfun): Don't copy DECL_ARGUMENTS nor DECL_RESULT here. Pass true as ABSTRACT_P to push_struct_function. Call targetm.target_option.relayout_function after it. (tree_function_versioning): Formatting fix. * gcc.target/i386/pr105554.c: New test.
