{"id":2226762,"url":"http://patchwork.ozlabs.org/api/patches/2226762/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/patch/bmm.hhup4p5wp2.gcc.gcc-TEST.pinskia.84.1.5@forge-stage.sourceware.org/","project":{"id":17,"url":"http://patchwork.ozlabs.org/api/projects/17/?format=json","name":"GNU Compiler Collection","link_name":"gcc","list_id":"gcc-patches.gcc.gnu.org","list_email":"gcc-patches@gcc.gnu.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"","list_archive_url":null,"date":"2026-04-22T18:49:13","name":"[v1,05/10] fab/forwprop: Move optimize stack restore to forwprop [PR121762]","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"7a025fa4cc3a35bbd48219a3a87baed6ebd40529","submitter":{"id":93219,"url":"http://patchwork.ozlabs.org/api/people/93219/?format=json","name":"Andrew Pinski via Sourceware Forge","email":"forge-bot+pinskia@forge-stage.sourceware.org"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/gcc/patch/bmm.hhup4p5wp2.gcc.gcc-TEST.pinskia.84.1.5@forge-stage.sourceware.org/mbox/","series":[{"id":501092,"url":"http://patchwork.ozlabs.org/api/series/501092/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=501092","date":"2026-04-22T18:49:11","name":"remove_fab","version":1,"mbox":"http://patchwork.ozlabs.org/series/501092/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2226762/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2226762/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":["incoming@patchwork.ozlabs.org","gcc-patches@gcc.gnu.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","gcc-patches@gcc.gnu.org"],"Authentication-Results":["legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=2620:52:6:3111::32; helo=vm01.sourceware.org;\n envelope-from=gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org;\n receiver=patchwork.ozlabs.org)","sourceware.org; dmarc=none (p=none dis=none)\n header.from=forge-stage.sourceware.org","sourceware.org;\n spf=pass smtp.mailfrom=forge-stage.sourceware.org","server2.sourceware.org;\n arc=none smtp.remote-ip=38.145.34.39"],"Received":["from vm01.sourceware.org (vm01.sourceware.org\n [IPv6:2620:52:6:3111::32])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g18P401Nyz1yGs\n\tfor ; Thu, 23 Apr 2026 05:27:03 +1000 (AEST)","from vm01.sourceware.org (localhost [127.0.0.1])\n\tby sourceware.org (Postfix) with ESMTP id 20461450B9EF\n\tfor ; Wed, 22 Apr 2026 19:26:59 +0000 (GMT)","from forge-stage.sourceware.org (vm08.sourceware.org [38.145.34.39])\n by sourceware.org (Postfix) with ESMTPS id 74A9C40A2C4D\n for ; Wed, 22 Apr 2026 18:50:43 +0000 (GMT)","from forge-stage.sourceware.org (localhost [IPv6:::1])\n (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n key-exchange x25519 server-signature ECDSA (prime256v1) server-digest SHA256)\n (No client certificate requested)\n by forge-stage.sourceware.org (Postfix) with ESMTPS id B677443594\n for ; Wed, 22 Apr 2026 18:50:41 +0000 (UTC)"],"DKIM-Filter":["OpenDKIM Filter v2.11.0 sourceware.org 20461450B9EF","OpenDKIM Filter v2.11.0 sourceware.org 74A9C40A2C4D"],"DMARC-Filter":"OpenDMARC Filter v1.4.2 sourceware.org 74A9C40A2C4D","ARC-Filter":"OpenARC Filter v1.0.0 sourceware.org 74A9C40A2C4D","ARC-Seal":"i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1776883843; cv=none;\n b=FTiMIDXANeI4xzckMrCX9BIghy/DD8OoIWibos9blcbCkFJLzNpfar+BKhRNJ9MSAnRwk+sYN4zHuakjoYHpdXJ2xKfwEwTfue6lDkFGONtSKPzY/aZSXLYWOYpQqHl4ls+TwUjfEsCI8q+mDEfrDqfheMSm7duh7vxGYDGvP8U=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=sourceware.org; s=key;\n t=1776883843; c=relaxed/simple;\n bh=gqMP1WkqAhaPqkW7X8StMypH9lqGa7G0jyAD4iHfZCU=;\n h=From:Date:Subject:To:Message-ID;\n b=Y0DalhZoiVkNXvRVPbWrG7FCOuFMmiKpxh+7JYd12cP+dwEObG5r5gmOFGvrwEmowt1OAWU4caqlly2sxfWKSqKA3ks5guII1vbOt/D5Lh+AxQJkwNHt1QtGDXEyPJJDIRDbk5WlyFRYgxWCX3MFAs+SJTKvDH6UKNUxAvzhAs4=","ARC-Authentication-Results":"i=1; server2.sourceware.org","From":"Andrew Pinski via Sourceware Forge\n ","Date":"Wed, 22 Apr 2026 18:49:13 +0000","Subject":"[PATCH v1 05/10] fab/forwprop: Move optimize stack restore to\n forwprop [PR121762]","To":"gcc-patches mailing list ","Message-ID":"\n ","X-Mailer":"batrachomyomachia","X-Pull-Request-Organization":"gcc","X-Pull-Request-Repository":"gcc-TEST","X-Pull-Request":"https://forge.sourceware.org/gcc/gcc-TEST/pulls/84","References":"\n ","In-Reply-To":"\n ","X-Patch-URL":"\n https://forge.sourceware.org/pinskia/gcc-TEST/commit/978e5248cb2331f4997502eed34e2fedb9a8052d","X-BeenThere":"gcc-patches@gcc.gnu.org","X-Mailman-Version":"2.1.30","Precedence":"list","List-Id":"Gcc-patches mailing list ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Reply-To":"gcc-patches mailing list ,\n pinskia@gcc.gnu.org","Errors-To":"gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org"},"content":"From: Andrew Pinski \n\nThis moves the removal of redundant stack restore from fab to forwprop.\nThere is a possibility of removing some of the redundant stack restores\nbefore the last folding but that is for a different patch.\n\nBootstrapped and tested on x86_64-linux-gnu.\n\n\tPR tree-optimization/121762\ngcc/ChangeLog:\n\n\t* tree-ssa-ccp.cc (optimize_stack_restore): Move to tree-ssa-forwprop.cc.\n\t(pass_fold_builtins::execute): Don't call optimize_stack_restore.\n\t* tree-ssa-forwprop.cc (optimize_stack_restore): New function from\n\ttree-ssa-ccp.cc. Return bool instead of value, use replace_call_with_value\n\tistead of returning integer_zero_node.\n\t(simplify_builtin_call): Call optimize_stack_restore.\n\nSigned-off-by: Andrew Pinski \n---\n gcc/tree-ssa-ccp.cc | 113 ---------------------------------------\n gcc/tree-ssa-forwprop.cc | 109 +++++++++++++++++++++++++++++++++++++\n 2 files changed, 109 insertions(+), 113 deletions(-)","diff":"diff --git a/gcc/tree-ssa-ccp.cc b/gcc/tree-ssa-ccp.cc\nindex d2c133345cd7..739d3be91293 100644\n--- a/gcc/tree-ssa-ccp.cc\n+++ b/gcc/tree-ssa-ccp.cc\n@@ -3085,112 +3085,6 @@ make_pass_ccp (gcc::context *ctxt)\n return new pass_ccp (ctxt);\n }\n \n-\n-\n-/* Try to optimize out __builtin_stack_restore. Optimize it out\n- if there is another __builtin_stack_restore in the same basic\n- block and no calls or ASM_EXPRs are in between, or if this block's\n- only outgoing edge is to EXIT_BLOCK and there are no calls or\n- ASM_EXPRs after this __builtin_stack_restore.\n- Note restore right before a noreturn function is not needed.\n- And skip some cheap calls that will most likely become an instruction. */\n-\n-static tree\n-optimize_stack_restore (gimple_stmt_iterator i)\n-{\n- tree callee;\n- gimple *stmt;\n-\n- basic_block bb = gsi_bb (i);\n- gimple *call = gsi_stmt (i);\n-\n- if (gimple_code (call) != GIMPLE_CALL\n- || gimple_call_num_args (call) != 1\n- || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME\n- || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0))))\n- return NULL_TREE;\n-\n- for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i))\n- {\n- stmt = gsi_stmt (i);\n- if (is_a (stmt))\n-\treturn NULL_TREE;\n- gcall *call = dyn_cast(stmt);\n- if (!call)\n-\tcontinue;\n-\n- /* We can remove the restore in front of noreturn\n-\t calls. Since the restore will happen either\n-\t via an unwind/longjmp or not at all. */\n- if (gimple_call_noreturn_p (call))\n-\tbreak;\n-\n- /* Internal calls are ok, to bypass\n-\t check first since fndecl will be null. */\n- if (gimple_call_internal_p (call))\n-\tcontinue;\n-\n- callee = gimple_call_fndecl (call);\n- /* Non-builtin calls are not ok. */\n- if (!callee\n-\t || !fndecl_built_in_p (callee))\n-\treturn NULL_TREE;\n-\n- /* Do not remove stack updates before strub leave. */\n- if (fndecl_built_in_p (callee, BUILT_IN___STRUB_LEAVE)\n-\t /* Alloca calls are not ok either. */\n-\t || fndecl_builtin_alloc_p (callee))\n-\treturn NULL_TREE;\n-\n- if (fndecl_built_in_p (callee, BUILT_IN_STACK_RESTORE))\n-\tgoto second_stack_restore;\n-\n- /* If not a simple or inexpensive builtin, then it is not ok either. */\n- if (!is_simple_builtin (callee)\n-\t && !is_inexpensive_builtin (callee))\n-\treturn NULL_TREE;\n- }\n-\n- /* Allow one successor of the exit block, or zero successors. */\n- switch (EDGE_COUNT (bb->succs))\n- {\n- case 0:\n- break;\n- case 1:\n- if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))\n-\treturn NULL_TREE;\n- break;\n- default:\n- return NULL_TREE;\n- }\n- second_stack_restore:\n-\n- /* If there's exactly one use, then zap the call to __builtin_stack_save.\n- If there are multiple uses, then the last one should remove the call.\n- In any case, whether the call to __builtin_stack_save can be removed\n- or not is irrelevant to removing the call to __builtin_stack_restore. */\n- if (has_single_use (gimple_call_arg (call, 0)))\n- {\n- gimple *stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0));\n- if (is_gimple_call (stack_save))\n-\t{\n-\t callee = gimple_call_fndecl (stack_save);\n-\t if (callee && fndecl_built_in_p (callee, BUILT_IN_STACK_SAVE))\n-\t {\n-\t gimple_stmt_iterator stack_save_gsi;\n-\t tree rhs;\n-\n-\t stack_save_gsi = gsi_for_stmt (stack_save);\n-\t rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0);\n-\t replace_call_with_value (&stack_save_gsi, rhs);\n-\t }\n-\t}\n- }\n-\n- /* No effect, so the statement will be deleted. */\n- return integer_zero_node;\n-}\n-\n /* If va_list type is a simple pointer and nothing special is needed,\n optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0),\n __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple\n@@ -4342,13 +4236,6 @@ pass_fold_builtins::execute (function *fun)\n \t switch (DECL_FUNCTION_CODE (callee))\n \t\t{\n \n-\t\tcase BUILT_IN_STACK_RESTORE:\n-\t\t result = optimize_stack_restore (i);\n-\t\t if (result)\n-\t\t break;\n-\t\t gsi_next (&i);\n-\t\t continue;\n-\n \t\tcase BUILT_IN_UNREACHABLE:\n \t\t if (optimize_unreachable (i))\n \t\t cfg_changed = true;\ndiff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc\nindex 917f3d90f6c2..06ce34c6782c 100644\n--- a/gcc/tree-ssa-forwprop.cc\n+++ b/gcc/tree-ssa-forwprop.cc\n@@ -2132,6 +2132,113 @@ simplify_builtin_memcpy_memset (gimple_stmt_iterator *gsi_p, gcall *stmt2)\n }\n }\n \n+\n+/* Try to optimize out __builtin_stack_restore. Optimize it out\n+ if there is another __builtin_stack_restore in the same basic\n+ block and no calls or ASM_EXPRs are in between, or if this block's\n+ only outgoing edge is to EXIT_BLOCK and there are no calls or\n+ ASM_EXPRs after this __builtin_stack_restore.\n+ Note restore right before a noreturn function is not needed.\n+ And skip some cheap calls that will most likely become an instruction. */\n+\n+static bool\n+optimize_stack_restore (gimple_stmt_iterator *gsi, gimple *call)\n+{\n+ if (!(cfun->curr_properties & PROP_last_full_fold))\n+ return false;\n+ tree callee;\n+ gimple *stmt;\n+\n+ basic_block bb = gsi_bb (*gsi);\n+\n+ if (gimple_call_num_args (call) != 1\n+ || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME\n+ || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0))))\n+ return false;\n+\n+ gimple_stmt_iterator i = *gsi;\n+ for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i))\n+ {\n+ stmt = gsi_stmt (i);\n+ if (is_a (stmt))\n+\treturn false;\n+ gcall *call = dyn_cast(stmt);\n+ if (!call)\n+\tcontinue;\n+\n+ /* We can remove the restore in front of noreturn\n+\t calls. Since the restore will happen either\n+\t via an unwind/longjmp or not at all. */\n+ if (gimple_call_noreturn_p (call))\n+\tbreak;\n+\n+ /* Internal calls are ok, to bypass\n+\t check first since fndecl will be null. */\n+ if (gimple_call_internal_p (call))\n+\tcontinue;\n+\n+ callee = gimple_call_fndecl (call);\n+ /* Non-builtin calls are not ok. */\n+ if (!callee\n+\t || !fndecl_built_in_p (callee))\n+\treturn false;\n+\n+ /* Do not remove stack updates before strub leave. */\n+ if (fndecl_built_in_p (callee, BUILT_IN___STRUB_LEAVE)\n+\t /* Alloca calls are not ok either. */\n+\t || fndecl_builtin_alloc_p (callee))\n+\treturn false;\n+\n+ if (fndecl_built_in_p (callee, BUILT_IN_STACK_RESTORE))\n+\tgoto second_stack_restore;\n+\n+ /* If not a simple or inexpensive builtin, then it is not ok either. */\n+ if (!is_simple_builtin (callee)\n+\t && !is_inexpensive_builtin (callee))\n+\treturn false;\n+ }\n+\n+ /* Allow one successor of the exit block, or zero successors. */\n+ switch (EDGE_COUNT (bb->succs))\n+ {\n+ case 0:\n+ break;\n+ case 1:\n+ if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))\n+\treturn false;\n+ break;\n+ default:\n+ return false;\n+ }\n+ second_stack_restore:\n+\n+ /* If there's exactly one use, then zap the call to __builtin_stack_save.\n+ If there are multiple uses, then the last one should remove the call.\n+ In any case, whether the call to __builtin_stack_save can be removed\n+ or not is irrelevant to removing the call to __builtin_stack_restore. */\n+ if (has_single_use (gimple_call_arg (call, 0)))\n+ {\n+ gimple *stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0));\n+ if (is_gimple_call (stack_save))\n+\t{\n+\t callee = gimple_call_fndecl (stack_save);\n+\t if (callee && fndecl_built_in_p (callee, BUILT_IN_STACK_SAVE))\n+\t {\n+\t gimple_stmt_iterator stack_save_gsi;\n+\t tree rhs;\n+\n+\t stack_save_gsi = gsi_for_stmt (stack_save);\n+\t rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0);\n+\t replace_call_with_value (&stack_save_gsi, rhs);\n+\t }\n+\t}\n+ }\n+\n+ /* No effect, so the statement will be deleted. */\n+ replace_call_with_value (gsi, NULL_TREE);\n+ return true;\n+}\n+\n /* *GSI_P is a GIMPLE_CALL to a builtin function.\n Optimize\n memcpy (p, \"abcd\", 4);\n@@ -2163,6 +2270,8 @@ simplify_builtin_call (gimple_stmt_iterator *gsi_p, tree callee2, bool full_walk\n \n switch (DECL_FUNCTION_CODE (callee2))\n {\n+ case BUILT_IN_STACK_RESTORE:\n+ return optimize_stack_restore (gsi_p, as_a(stmt2));\n case BUILT_IN_MEMCMP:\n case BUILT_IN_MEMCMP_EQ:\n return simplify_builtin_memcmp (gsi_p, as_a(stmt2));\n","prefixes":["v1","05/10"]}