From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id BD80138582AE; Wed, 20 Dec 2023 01:56:22 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org BD80138582AE DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1703037382; bh=hTpZZ2Dkhyh96Fb3lAKsW3+DmYUfUFxvrPiPFLRP+vs=; h=From:To:Subject:Date:In-Reply-To:References:From; b=L2PPKIUy3oKG9zw8PmYVcYRPeuvWE5NPAQacbOlfzO9CpzQRKnyhWM5swCdl4GVPX siATQk4auodQjPqnGZ4t7UYSI3lM6vpqsnpYkqszP+BGWU1ZC2rAuS2NKZbwtNCqNQ i2iog+Q4ckFavB1jW4QyC3Nok1Uo4l/msxHoHfuo= From: "cvs-commit at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/108975] [11 Regression] ICE on constexpr variable used as nontype template since r9-5473-ge32fc4499f863f Date: Wed, 20 Dec 2023 01:56:22 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c++ X-Bugzilla-Version: 12.1.0 X-Bugzilla-Keywords: c++-lambda, ice-on-valid-code X-Bugzilla-Severity: normal X-Bugzilla-Who: cvs-commit at gcc dot gnu.org X-Bugzilla-Status: ASSIGNED X-Bugzilla-Resolution: X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: ppalka at gcc dot gnu.org X-Bugzilla-Target-Milestone: 11.4 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108975 --- Comment #23 from GCC Commits --- The releases/gcc-11 branch has been updated by Patrick Palka : https://gcc.gnu.org/g:a53f988e36132761c8fe17da421b736e737dec30 commit r11-11161-ga53f988e36132761c8fe17da421b736e737dec30 Author: Patrick Palka Date: Tue Apr 25 15:59:22 2023 -0400 c++: value dependence of by-ref lambda capture [PR108975] We are still ICEing on the generic lambda version of the testcase from this PR, even after r13-6743-g6f90de97634d6f, due to the by-ref capture of the constant local variable 'dim' being considered value-dependent when regenerating the lambda (at which point processing_template_decl is set since the lambda is generic), which prevents us from constant foldi= ng its uses. Later during prune_lambda_captures we end up not thoroughly walking the body of the lambda and overlook the (non-folded) uses of 'dim' within the array bound and using-decls. We could fix this by making prune_lambda_captures walk the body of the lambda more thoroughly so that it finds these uses of 'dim', but ideally we should be able to constant fold all uses of 'dim' ahead of time and prune the implicit capture after all. To that end this patch makes value_dependent_expression_p return false for such by-ref captures of constant local variables, allowing their uses to get constant folded ahead of time. It seems we just need to disable the predicate's conservative early exit for reference variables (added by r5-5022-g51d72abe5ea04e) when DECL_HAS_VALUE_EXPR_P. This effectively makes us treat by-value and by-ref captures more consistent= ly when it comes to value dependence. PR c++/108975 gcc/cp/ChangeLog: * pt.c (value_dependent_expression_p) : Suppress conservative early exit for reference variables when DECL_HAS_VALUE_EXPR_P. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/lambda/lambda-const11a.C: New test. (cherry picked from commit 3d674e29d7f89bf93fcfcc963ff0248c6347586d)=