From: Andi Kleen Date: Sun, 2 Jun 2024 05:04:41 +0000 (-0700) Subject: Fix pro_and_epilogue for sibcalls at -O0 (PR115255) X-Git-Tag: basepoints/gcc-16~7430 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=983daf0e5fdaada5b930374c21455d42d34350be;p=thirdparty%2Fgcc.git Fix pro_and_epilogue for sibcalls at -O0 (PR115255) Some of the cfg fixups in pro_and_epilogue for sibcalls were dependent on "optimize". Make them check cfun->tail_call_marked instead to handle the -O0 musttail case. This fixes the musttail test cases on arm targets. gcc/ChangeLog: PR target/115255 * function.cc (thread_prologue_and_epilogue_insns): Check cfun->tail_call_marked for sibcalls too. (rest_of_handle_thread_prologue_and_epilogue): Dito. --- diff --git a/gcc/function.cc b/gcc/function.cc index 4edd4da1247..a6f6de34942 100644 --- a/gcc/function.cc +++ b/gcc/function.cc @@ -2231,6 +2231,7 @@ use_register_for_decl (const_tree decl) /* We don't set DECL_IGNORED_P for the function_result_decl. */ if (optimize) return true; + /* Needed for [[musttail]] which can operate even at -O0 */ if (cfun->tail_call_marked) return true; /* We don't set DECL_REGISTER for the function_result_decl. */ @@ -6259,8 +6260,11 @@ thread_prologue_and_epilogue_insns (void) } /* Threading the prologue and epilogue changes the artificial refs in the - entry and exit blocks, and may invalidate DF info for tail calls. */ + entry and exit blocks, and may invalidate DF info for tail calls. + This is also needed for [[musttail]] conversion even when not + optimizing. */ if (optimize + || cfun->tail_call_marked || flag_optimize_sibling_calls || flag_ipa_icf_functions || in_lto_p) @@ -6557,7 +6561,7 @@ rest_of_handle_thread_prologue_and_epilogue (function *fun) { /* prepare_shrink_wrap is sensitive to the block structure of the control flow graph, so clean it up first. */ - if (optimize) + if (cfun->tail_call_marked || optimize) cleanup_cfg (0); /* On some machines, the prologue and epilogue code, or parts thereof,