public inbox for gcc-cvs@sourceware.org help / color / mirror / Atom feed
From: Richard Biener <rguenth@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc r12-7050] Adjust LSHIFT_EXPR handling of multiple_of_p Date: Fri, 4 Feb 2022 11:54:52 +0000 (GMT) [thread overview] Message-ID: <20220204115452.C604C3858D20@sourceware.org> (raw) https://gcc.gnu.org/g:24c72fb0eedfe7c67f9b15aa31b474a999cc4723 commit r12-7050-g24c72fb0eedfe7c67f9b15aa31b474a999cc4723 Author: Richard Biener <rguenther@suse.de> Date: Mon Jan 24 15:26:46 2022 +0100 Adjust LSHIFT_EXPR handling of multiple_of_p This removes the odd check of size_type_node when handling left-shifts as multiplications of 1 << N and instead uses the type as specified. It also moves left-shift handling next to multiplications where it semantically belongs. 2022-01-24 Richard Biener <rguenther@suse.de> * fold-const.cc (multiple_of_p): Re-write and move LSHIFT_EXPR handling. Diff: --- gcc/fold-const.cc | 33 ++++++++++++++++----------------- 1 file changed, 16 insertions(+), 17 deletions(-) diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc index 8fc01cdfb77..12732d39c79 100644 --- a/gcc/fold-const.cc +++ b/gcc/fold-const.cc @@ -14079,7 +14079,7 @@ int multiple_of_p (tree type, const_tree top, const_tree bottom) { gimple *stmt; - tree t1, op1, op2; + tree op1, op2; if (operand_equal_p (top, bottom, 0)) return 1; @@ -14125,6 +14125,21 @@ multiple_of_p (tree type, const_tree top, const_tree bottom) return (multiple_of_p (type, TREE_OPERAND (top, 1), bottom) || multiple_of_p (type, TREE_OPERAND (top, 0), bottom)); + case LSHIFT_EXPR: + /* Handle X << CST as X * (1 << CST) and only process the constant. */ + if (TREE_CODE (TREE_OPERAND (top, 1)) == INTEGER_CST) + { + op1 = TREE_OPERAND (top, 1); + if (wi::to_widest (op1) < TYPE_PRECISION (type)) + { + wide_int mul_op + = wi::one (TYPE_PRECISION (type)) << wi::to_wide (op1); + return multiple_of_p (type, + wide_int_to_tree (type, mul_op), bottom); + } + } + return 0; + case MINUS_EXPR: /* It is impossible to prove if op0 - op1 is multiple of bottom precisely, so be conservative here checking if both op0 and op1 @@ -14144,22 +14159,6 @@ multiple_of_p (tree type, const_tree top, const_tree bottom) return (multiple_of_p (type, op1, bottom) && multiple_of_p (type, TREE_OPERAND (top, 0), bottom)); - case LSHIFT_EXPR: - if (TREE_CODE (TREE_OPERAND (top, 1)) == INTEGER_CST) - { - op1 = TREE_OPERAND (top, 1); - /* const_binop may not detect overflow correctly, - so check for it explicitly here. */ - if (wi::gtu_p (TYPE_PRECISION (TREE_TYPE (size_one_node)), - wi::to_wide (op1)) - && (t1 = fold_convert (type, - const_binop (LSHIFT_EXPR, size_one_node, - op1))) != 0 - && !TREE_OVERFLOW (t1)) - return multiple_of_p (type, t1, bottom); - } - return 0; - CASE_CONVERT: /* Can't handle conversions from non-integral or wider integral type. */ if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE)
reply other threads:[~2022-02-04 11:54 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20220204115452.C604C3858D20@sourceware.org \ --to=rguenth@gcc.gnu.org \ --cc=gcc-cvs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).