From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2122) id 4E0463857013; Sat, 22 Apr 2023 00:23:13 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 4E0463857013 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1682122993; bh=glSfNjo2BK0ZVZVCRdHj6uSdgvuWPvK/ws6aMIt/SrU=; h=From:To:Subject:Date:From; b=JmW2hdtKQasDT29MzKhkGdamA7GfHmiJrtXLffeZbYkXXjG7I4S28TGWuesVx2Xx9 e2DKmE+PUBHf08rzA8bSnq6RqhDILlkCEhkDvjsCASwgtyfPO90aRGJHvJHREhHily SxJ3rauHFFftQcQEt1hqNxisX9c1UIWa/fIzFj88= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Jason Merrill To: gcc-cvs@gcc.gnu.org Subject: [gcc r11-10647] c-family: -Wsequence-point and COMPONENT_REF [PR107163] X-Act-Checkin: gcc X-Git-Author: Jason Merrill X-Git-Refname: refs/heads/releases/gcc-11 X-Git-Oldrev: b6c8048cdd2c1e523f663f248ba39caed5af90e7 X-Git-Newrev: 9ab083eb8a96b7f8baf6fe632d03aa496017e456 Message-Id: <20230422002313.4E0463857013@sourceware.org> Date: Sat, 22 Apr 2023 00:23:13 +0000 (GMT) List-Id: https://gcc.gnu.org/g:9ab083eb8a96b7f8baf6fe632d03aa496017e456 commit r11-10647-g9ab083eb8a96b7f8baf6fe632d03aa496017e456 Author: Jason Merrill Date: Thu Mar 23 15:57:39 2023 -0400 c-family: -Wsequence-point and COMPONENT_REF [PR107163] The patch for PR91415 fixed -Wsequence-point to treat shifts and ARRAY_REF as sequenced in C++17, and COMPONENT_REF as well. But this is unnecessary for COMPONENT_REF, since the RHS is just a FIELD_DECL with no actual evaluation, and in this testcase handling COMPONENT_REF as sequenced blows up fast in a deep inheritance tree. Instead, look through it. PR c++/107163 gcc/c-family/ChangeLog: * c-common.c (verify_tree): Don't use sequenced handling for COMPONENT_REF. gcc/testsuite/ChangeLog: * g++.dg/warn/Wsequence-point-5.C: New test. Diff: --- gcc/c-family/c-common.c | 7 ++++- gcc/testsuite/g++.dg/warn/Wsequence-point-5.C | 37 +++++++++++++++++++++++++++ 2 files changed, 43 insertions(+), 1 deletion(-) diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c index 16fc52302e5..9417b7fb4d1 100644 --- a/gcc/c-family/c-common.c +++ b/gcc/c-family/c-common.c @@ -2023,12 +2023,17 @@ verify_tree (tree x, struct tlist **pbefore_sp, struct tlist **pno_sp, case LSHIFT_EXPR: case RSHIFT_EXPR: - case COMPONENT_REF: case ARRAY_REF: if (cxx_dialect >= cxx17) goto sequenced_binary; goto do_default; + case COMPONENT_REF: + /* Treat as unary, the other operands aren't evaluated. */ + x = TREE_OPERAND (x, 0); + writer = 0; + goto restart; + default: do_default: /* For other expressions, simply recurse on their operands. diff --git a/gcc/testsuite/g++.dg/warn/Wsequence-point-5.C b/gcc/testsuite/g++.dg/warn/Wsequence-point-5.C new file mode 100644 index 00000000000..0354ab09f53 --- /dev/null +++ b/gcc/testsuite/g++.dg/warn/Wsequence-point-5.C @@ -0,0 +1,37 @@ +// PR c++/107163 +// { dg-additional-options "-Wsequence-point" } + +struct BaseType { + int i; +}; + +template< int Seq > +class DerivedType : public DerivedType< Seq - 1 > { }; + +template<> +class DerivedType< -1 > : public BaseType { }; + +int main() { + DerivedType< 400 > d; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + d.i = 42; + return d.i; +}