{"id":2230107,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2230107/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/patch/20260429090406.A96D74BB24E6@sourceware.org/","project":{"id":17,"url":"http://patchwork.ozlabs.org/api/1.1/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},"msgid":"<20260429090406.A96D74BB24E6@sourceware.org>","date":"2026-04-29T09:03:36","name":"tree-optimization/120702 - avoid folding loads to STRING_CSTs","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"c65be390b903b93f51dbe43824da89a6311f2f38","submitter":{"id":4338,"url":"http://patchwork.ozlabs.org/api/1.1/people/4338/?format=json","name":"Richard Biener","email":"rguenther@suse.de"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/gcc/patch/20260429090406.A96D74BB24E6@sourceware.org/mbox/","series":[{"id":502019,"url":"http://patchwork.ozlabs.org/api/1.1/series/502019/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=502019","date":"2026-04-29T09:03:36","name":"tree-optimization/120702 - avoid folding loads to STRING_CSTs","version":1,"mbox":"http://patchwork.ozlabs.org/series/502019/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2230107/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2230107/checks/","tags":{},"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\tdkim=pass (1024-bit key;\n unprotected) header.d=suse.de header.i=@suse.de header.a=rsa-sha256\n header.s=susede2_rsa header.b=OLdZhXqF;\n\tdkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=B92vIHLm;\n\tdkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de\n header.a=rsa-sha256 header.s=susede2_rsa header.b=dWVPkvbG;\n\tdkim=neutral header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=VO9C8sUv;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=2620:52:6:3111::32; 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charset=US-ASCII","X-Spamd-Result":"default: False [-1.80 / 50.00]; BAYES_HAM(-3.00)[100.00%];\n MISSING_MID(2.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000];\n NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain];\n FROM_HAS_DN(0.00)[]; MIME_TRACE(0.00)[0:+];\n MISSING_XM_UA(0.00)[]; ARC_NA(0.00)[];\n RCVD_COUNT_ZERO(0.00)[0]; TO_DN_SOME(0.00)[];\n FROM_EQ_ENVFROM(0.00)[]; FUZZY_RATELIMITED(0.00)[rspamd.com];\n TO_MATCH_ENVRCPT_ALL(0.00)[];\n DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519];\n RCPT_COUNT_THREE(0.00)[3]","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 ","Errors-To":"gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org","Message-Id":"<20260429090406.A96D74BB24E6@sourceware.org>"},"content":"The following avoids (large) string duplication which can happen\nwhen folding aggregate reads to STRING_CSTs. There's unlikely\nto be followup optimization opportunities.\n\nBootstrapped and tested on x86-64-unknown-linuyx-gnu (I was surprised\nthere's no diagnostic testcase fallout).\n\nOK for trunk?\n\nThanks,\nRichard.\n\n\tPR tree-optimization/120702\n\t* gimple-fold.cc (maybe_fold_reference): Only fold\n\tregister type reads.\n\n\t* gcc.dg/tree-ssa/pr120702.c: New testcase.\n---\n gcc/gimple-fold.cc | 5 +++++\n gcc/testsuite/gcc.dg/tree-ssa/pr120702.c | 25 ++++++++++++++++++++++++\n 2 files changed, 30 insertions(+)\n create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr120702.c","diff":"diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc\nindex 501c1245116..b53478dbb3d 100644\n--- a/gcc/gimple-fold.cc\n+++ b/gcc/gimple-fold.cc\n@@ -306,6 +306,11 @@ maybe_fold_reference (tree expr)\n {\n tree result = NULL_TREE;\n \n+ /* Avoid expensive fold_const_aggregate_ref early on aggregate loads\n+ and esp. replacing STRING_CSTs inline. */\n+ if (!is_gimple_reg_type (TREE_TYPE (expr)))\n+ return NULL_TREE;\n+\n if ((TREE_CODE (expr) == VIEW_CONVERT_EXPR\n || TREE_CODE (expr) == REALPART_EXPR\n || TREE_CODE (expr) == IMAGPART_EXPR)\ndiff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr120702.c b/gcc/testsuite/gcc.dg/tree-ssa/pr120702.c\nnew file mode 100644\nindex 00000000000..fb0f8f73a73\n--- /dev/null\n+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr120702.c\n@@ -0,0 +1,25 @@\n+/* { dg-do compile } */\n+/* { dg-options \"-Os -fdump-tree-optimized\" } */\n+\n+extern void *memcpy(void *, const void *, __SIZE_TYPE__);\n+extern int memcmp(const void *, const void *, __SIZE_TYPE__);\n+\n+static const unsigned char orig[10]\n+ = { 'J', '2', 'O', 'Z', 'F', '5', '0', 'F', 'Y', 'L' };\n+\n+static unsigned char test[10];\n+\n+int\n+verify (void)\n+{\n+ return 0 == memcmp (test, orig, 10 * sizeof (orig[0]));\n+}\n+\n+int\n+benchmark (void)\n+{\n+ memcpy (test, orig, 10 * sizeof (orig[0]));\n+ return 0;\n+}\n+\n+/* { dg-final { scan-tree-dump-not \" = \\\"J2OZF50FYL\\\";\" \"optimized\" } } */\n","prefixes":[]}