From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 9B4FD3858422; Fri, 1 Oct 2021 06:51:25 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9B4FD3858422 From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/102285] New flag -ftrivial-auto-var-init=zero causes crash in pr82421.c Date: Fri, 01 Oct 2021 06:51:25 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: middle-end X-Bugzilla-Version: 12.0 X-Bugzilla-Keywords: ice-on-valid-code X-Bugzilla-Severity: normal X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: ASSIGNED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: qinzhao at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- 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 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 01 Oct 2021 06:51:25 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102285 --- Comment #13 from Richard Biener --- Because the variable doesn't need to be addressable. OK, so the issue is likely that we're probing the lhs with EXPAND_WRITE but when we expand the memset we end up with using expand_expr_addr_expr_1 with EXPAND_NORMAL. So our probe ends up with (mem/c:BLK (plus:DI (reg/f:DI 77 virtual-stack-vars) (const_int -16 [0xfffffffffffffff0])) [0 S-1 A128]) which means it created a stack slot - that's not what we intended. We could try sth like the following which should cover this testcase and also hopefully doesn't break anything else. diff --git a/gcc/expr.c b/gcc/expr.c index e0bcbccd905..ab3b5b26c20 100644 --- a/gcc/expr.c +++ b/gcc/expr.c @@ -5322,7 +5322,7 @@ non_mem_decl_p (tree base) /* Returns true if REF refers to an object that does not reside in memory and has non-BLKmode. */ -static inline bool +bool mem_ref_refers_to_non_mem_p (tree ref) { tree base; diff --git a/gcc/expr.h b/gcc/expr.h index 94a85b40dca..85650e96834 100644 --- a/gcc/expr.h +++ b/gcc/expr.h @@ -346,4 +346,6 @@ extern void expand_operands (tree, tree, rtx, rtx*, rtx= *, /* Return an rtx for the size in bytes of the value of an expr. */ extern rtx expr_size (tree); +extern bool mem_ref_refers_to_non_mem_p (tree ref); + #endif /* GCC_EXPR_H */ diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c index 8312d08aab2..c1d23dfd21e 100644 --- a/gcc/internal-fn.c +++ b/gcc/internal-fn.c @@ -3015,8 +3015,10 @@ expand_DEFERRED_INIT (internal_fn, gcall *stmt) reg_lhs =3D true; else { - rtx tem =3D expand_expr (lhs, NULL_RTX, VOIDmode, EXPAND_WRITE); - reg_lhs =3D !MEM_P (tem); + tree lhs_base =3D lhs; + while (handled_component_p (lhs_base)) + lhs_base =3D TREE_OPERAND (lhs_base, 0); + reg_lhs =3D mem_refers_to_non_mem_p (lhs_base); } if (!reg_lhs)=