[{"id":3683856,"web_url":"http://patchwork.ozlabs.org/comment/3683856/","msgid":"<4166p42q-26sn-pqsp-8q8n-3n0s9104943p@fhfr.qr>","list_archive_url":null,"date":"2026-04-29T07:29:38","subject":"Re: [PATCH] bitintlower: Padding bit fixes, part 6 [PR123635]","submitter":{"id":4338,"url":"http://patchwork.ozlabs.org/api/people/4338/","name":"Richard Biener","email":"rguenther@suse.de"},"content":"On Wed, 29 Apr 2026, Jakub Jelinek wrote:\n\n> Hi!\n> \n> I've missed torture/bitint-{93,94}.c FAILs on s390x-linux (i.e. big endian).\n> For __builtin_mul_overflow, the code to extend the partial most significant\n> limb is done before memmoving it down, so that limb actually isn't on big\n> endian at offset 0 but is nelts - obj_nelts. The following patch computes\n> obj_nelts first, uses it on big-endian and so that the offset checking\n> asserts don't trigger, on big-endian also uses NULL_TREE first argument to\n> limb_access.\n> \n> Bootstrapped/regtested on x86_64-linux, i686-linux, powerpc64le-linux,\n> aarch64-linux and s390x-linux, ok for trunk and 16.2?\n\nOK\n\n> 2026-04-29 Jakub Jelinek \n> \n> \tPR middle-end/123635\n> \t* gimple-lower-bitint.cc (bitint_large_huge::finish_arith_overflow):\n> \tMove obj_nelts/atype computation before bitint_extended handling. For\n> \tbitint_big_endian in the bitint_extended handling use size_zero_node\n> \tonly for limb_access_type calls, otherwise use\n> \tsize_int (nelts - obj_nelts) and pass NULL_TREE as first argument to\n> \tlimb_access calls.\n> \n> --- gcc/gimple-lower-bitint.cc.jj\t2026-04-24 14:36:20.686912090 +0200\n> +++ gcc/gimple-lower-bitint.cc\t2026-04-28 16:58:30.724938682 +0200\n> @@ -4478,6 +4478,13 @@ bitint_large_huge::finish_arith_overflow\n> {\n> unsigned HOST_WIDE_INT obj_nelts = 0;\n> tree atype = NULL_TREE;\n> + if (obj)\n> +\t{\n> +\t obj_nelts = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (obj))) / limb_prec;\n> +\t if (orig_obj == NULL_TREE)\n> +\t obj_nelts >>= 1;\n> +\t atype = build_array_type_nelts (m_limb_type, obj_nelts);\n> +\t}\n> if (bitint_extended && (var || obj))\n> \t{\n> \t unsigned prec = TYPE_PRECISION (type);\n> @@ -4492,9 +4499,13 @@ bitint_large_huge::finish_arith_overflow\n> \t if ((code == MULT_EXPR && (prec % limb_prec) != 0)\n> \t || (ext_ms_limb && !TYPE_UNSIGNED (type)))\n> \t {\n> -\t tree plm1idx = size_int (bitint_big_endian ? 0 : prec_limbs - 1);\n> -\t tree plm1type = limb_access_type (type, plm1idx);\n> -\t tree l = limb_access (type, var ? var : obj, plm1idx, true);\n> +\t tree plm1idx = size_int (bitint_big_endian\n> +\t\t\t\t ? nelts - obj_nelts : prec_limbs - 1);\n> +\t tree plm1type\n> +\t\t= limb_access_type (type, bitint_big_endian\n> +\t\t\t\t\t ? size_zero_node : plm1idx);\n> +\t tree l = limb_access (bitint_big_endian ? NULL_TREE : type,\n> +\t\t\t\t var ? var : obj, plm1idx, true);\n> \t tree rhs = make_ssa_name (TREE_TYPE (l));\n> \t g = gimple_build_assign (rhs, l);\n> \t insert_before (g);\n> @@ -4505,7 +4516,8 @@ bitint_large_huge::finish_arith_overflow\n> \t\t if (!useless_type_conversion_p (TREE_TYPE (l),\n> \t\t\t\t\t\t TREE_TYPE (rhs)))\n> \t\t rhs = add_cast (TREE_TYPE (l), rhs);\n> -\t\t l = limb_access (type, var ? var : obj, plm1idx, true);\n> +\t\t l = limb_access (bitint_big_endian ? NULL_TREE : type,\n> +\t\t\t\t var ? var : obj, plm1idx, true);\n> \t\t g = gimple_build_assign (l, rhs);\n> \t\t insert_before (g);\n> \t\t}\n> @@ -4537,13 +4549,6 @@ bitint_large_huge::finish_arith_overflow\n> \t insert_before (g);\n> \t }\n> \t}\n> - if (obj)\n> -\t{\n> -\t obj_nelts = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (obj))) / limb_prec;\n> -\t if (orig_obj == NULL_TREE)\n> -\t obj_nelts >>= 1;\n> -\t atype = build_array_type_nelts (m_limb_type, obj_nelts);\n> -\t}\n> if (var && obj)\n> \t{\n> \t tree v1, v2;\n> \n> \tJakub\n> \n>","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=wt6p6Irp;\n\tdkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=zZu1ZUrt;\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=wt6p6Irp;\n\tdkim=neutral header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=zZu1ZUrt;\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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