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GET /api/patches/2218236/?format=api
{ "id": 2218236, "url": "http://patchwork.ozlabs.org/api/patches/2218236/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/patch/20260331182118.120657-1-konstantinos.eleftheriou@vrull.eu/", "project": { "id": 17, "url": "http://patchwork.ozlabs.org/api/projects/17/?format=api", "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": "<20260331182118.120657-1-konstantinos.eleftheriou@vrull.eu>", "list_archive_url": null, "date": "2026-03-31T18:21:18", "name": "avoid-store-forwarding: Re-apply extension after bit insert sequence [PR124713]", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "f1fc9a068b5b8c78aa17a02132f6e71d030f1670", "submitter": { "id": 89121, "url": "http://patchwork.ozlabs.org/api/people/89121/?format=api", "name": "Konstantinos Eleftheriou", "email": "konstantinos.eleftheriou@vrull.eu" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/gcc/patch/20260331182118.120657-1-konstantinos.eleftheriou@vrull.eu/mbox/", "series": [ { "id": 498239, "url": "http://patchwork.ozlabs.org/api/series/498239/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/list/?series=498239", "date": "2026-03-31T18:21:18", "name": "avoid-store-forwarding: Re-apply extension after bit insert sequence [PR124713]", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/498239/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2218236/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2218236/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org>", "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 (2048-bit key;\n unprotected) header.d=vrull.eu header.i=@vrull.eu header.a=rsa-sha256\n header.s=google header.b=p4NeBZFk;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=38.145.34.32; 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The bit-field insert operates on the\nfull-width destination register, but does not re-apply the\nextension, leaving stale upper bits from the original load.\n\nFix by emitting the corresponding extension after the bit insert\nsequence for non-eliminated extending loads, mirroring what the\nload-elimination path already does.\n\n\tPR rtl-optimization/124713\n\ngcc/ChangeLog:\n\n\t* avoid-store-forwarding.cc (process_store_forwarding): Re-apply\n\tSIGN_EXTEND/ZERO_EXTEND after bit insert sequence when the load is\n\tnot eliminated.\n\ngcc/testsuite/ChangeLog:\n\n\t* gcc.target/aarch64/pr124713.c: New test.\n---\n gcc/avoid-store-forwarding.cc | 30 +++++++++++++++------\n gcc/testsuite/gcc.target/aarch64/pr124713.c | 24 +++++++++++++++++\n 2 files changed, 46 insertions(+), 8 deletions(-)\n create mode 100644 gcc/testsuite/gcc.target/aarch64/pr124713.c", "diff": "diff --git a/gcc/avoid-store-forwarding.cc b/gcc/avoid-store-forwarding.cc\nindex 260c135c219f..65be6f1398de 100644\n--- a/gcc/avoid-store-forwarding.cc\n+++ b/gcc/avoid-store-forwarding.cc\n@@ -355,20 +355,34 @@ process_store_forwarding (vec<store_fwd_info> &stores, rtx_insn *load_insn,\n stores.ordered_remove (move_to_front);\n }\n \n- if (load_elim)\n+ machine_mode outer_mode = GET_MODE (SET_DEST (load));\n+ if (load_elim || outer_mode != load_mem_mode)\n {\n- machine_mode outer_mode = GET_MODE (SET_DEST (load));\n- rtx load_move;\n- rtx load_value = dest;\n+ /* If the load is being eliminated, emit a move (with extension if\n+\t needed) from the temp register to the original load destination.\n+\t Otherwise, if the load has SIGN_EXTEND or ZERO_EXTEND wrapping\n+\t the MEM, the bit insert sequence may have modified bits that\n+\t affect the extension (e.g. the sign bit), so re-apply it. */\n+ rtx move_src;\n if (outer_mode != load_mem_mode)\n \t{\n-\t load_value = simplify_gen_unary (GET_CODE (SET_SRC (load)),\n-\t\t\t\t\t outer_mode, dest, load_mem_mode);\n+\t rtx ext_op = dest;\n+\t if (!load_elim)\n+\t {\n+\t ext_op = lowpart_subreg (load_mem_mode, dest, outer_mode);\n+\t if (!ext_op)\n+\t\treturn false;\n+\t }\n+\t move_src = simplify_gen_unary (GET_CODE (SET_SRC (load)),\n+\t\t\t\t\t outer_mode, ext_op, load_mem_mode);\n \t}\n- load_move = gen_rtx_SET (SET_DEST (load), load_value);\n+ else\n+\tmove_src = dest;\n+\n+ rtx move = gen_rtx_SET (SET_DEST (load), move_src);\n \n start_sequence ();\n- rtx_insn *insn = emit_insn (load_move);\n+ rtx_insn *insn = emit_insn (move);\n rtx_insn *seq = end_sequence ();\n \n if (recog_memoized (insn) < 0)\ndiff --git a/gcc/testsuite/gcc.target/aarch64/pr124713.c b/gcc/testsuite/gcc.target/aarch64/pr124713.c\nnew file mode 100644\nindex 000000000000..798cf1fa9583\n--- /dev/null\n+++ b/gcc/testsuite/gcc.target/aarch64/pr124713.c\n@@ -0,0 +1,24 @@\n+/* PR rtl-optimization/124713 */\n+/* { dg-do run } */\n+/* { dg-require-effective-target aarch64_little_endian } */\n+/* { dg-options \"-Og -favoid-store-forwarding -fwrapv\" } */\n+\n+int x;\n+long y;\n+\n+__attribute__((noipa)) long\n+foo (short m)\n+{\n+ short b = m * 13;\n+ __builtin_memset (1 + (char *) &b, x, 1);\n+ long c = *(long *) __builtin_memset (&y, x, 4);\n+ return c + b;\n+}\n+\n+int\n+main ()\n+{\n+ long x = foo (3840);\n+ if (x)\n+ __builtin_abort ();\n+}\n", "prefixes": [] }