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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug ipa/102452] Structs with flexible array members are not optimized on stack Date: Thu, 23 Sep 2021 06:57:23 +0000 [thread overview] Message-ID: <bug-102452-4-ES2dQ0SfFP@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-102452-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102452 --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- get_three after einline w/o USE_FLEX_ARR defined (this is changing the type to int): <bb 2> : _5 = test_2(D)->is_a; if (_5 != 0) goto <bb 3>; [50.00%] else goto <bb 4>; [50.00%] <bb 3> : D.3292 = *test_2(D); goto <bb 5>; [100.00%] <bb 4> : _6 = test_2(D)->as.b.one; _7 = (long int) _6; _8 = test_2(D)->as.b.two; _9 = (long int) _8; _10 = test_2(D)->as.b.three; _11 = (long int) _10; D.3292.as.a.one = _7; D.3292.as.a.two = _9; D.3292.as.a.three = _11; <bb 5> : _4 = D.3292.as.a.three; return _4; With USE_FLEX_ARR defined to 1: <bb 2> : _5 = test_2(D)->is_a; if (_5 != 0) goto <bb 3>; [50.00%] else goto <bb 4>; [50.00%] <bb 3> : D.3293 = *test_2(D); goto <bb 5>; [100.00%] <bb 4> : _6 = test_2(D)->as.b.one; _7 = (long int) _6; ret.as.a.one = _7; _8 = test_2(D)->as.b.two; _9 = (long int) _8; ret.as.a.two = _9; _10 = test_2(D)->as.b.three; _11 = (long int) _10; ret.as.a.three = _11; D.3293 = ret; ret ={v} {CLOBBER}; <bb 5> : _4 = D.3293.as.a.three; return _4; as far as I can tell the IR is the same before that, even RSO: D.3293 = make_test_a (test_2(D)); [return slot optimization] But it looks in the case of the flex array case, RSO does not actually happen.
next prev parent reply other threads:[~2021-09-23 6:57 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-22 13:22 [Bug c/102452] New: " peter at peterzhu dot ca 2021-09-22 17:49 ` [Bug ipa/102452] " pinskia at gcc dot gnu.org 2021-09-23 6:42 ` rguenth at gcc dot gnu.org 2021-09-23 6:57 ` pinskia at gcc dot gnu.org [this message] 2021-09-23 7:05 ` [Bug tree-optimization/102452] " pinskia at gcc dot gnu.org 2021-09-23 7:16 ` rguenther at suse dot de 2021-09-23 7:21 ` rguenther at suse dot de
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