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From: "luoxhu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/22326] promotions (from float to double) are not removed when they should be able to Date: Fri, 27 Nov 2020 06:20:30 +0000 [thread overview] Message-ID: <bug-22326-4-km5S3ZSZOA@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-22326-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=22326 --- Comment #13 from luoxhu at gcc dot gnu.org --- Tried implementation with backprop, found that this model seems not suitable for double promotion remove with BACK propagation. i.e: 1) mad1.c float foo (float x, float y, float z) { return ( y * fabs (x) + z ); } mad1.c.098t.cunrolli: foo (float x, float y, float z) { double _1; float _2; double _3; double _4; double _5; double _6; float _10; <bb 2> [local count: 1073741824]: _1 = (double) y_7(D); _2 = ABS_EXPR <x_8(D)>; _3 = (double) _2; _4 = _1 * _3; _5 = (double) z_9(D); _6 = _4 + _5; _10 = (float) _6; return _10; } mad1.c.099t.backprop: [USE] _10 in return _10; [USE] _6 in _10 = (float) _6; _6: convert from float to double not important [DEF] Recording new information for _6 = _4 + _5; _6: convert from float to double not important [USE] _5 in _6 = _4 + _5; _5: convert from float to double not important [DEF] Recording new information for _5 = (double) z_9(D); _5: convert from float to double not important [USE] _4 in _6 = _4 + _5; _4: convert from float to double not important [DEF] Recording new information for _4 = _1 * _3; _4: convert from float to double not important [USE] _3 in _4 = _1 * _3; _3: convert from float to double not important [DEF] Recording new information for _3 = (double) _2; _3: convert from float to double not important [USE] _2 in _3 = (double) _2; _2: convert from float to double not important [DEF] Recording new information for _2 = ABS_EXPR <x_8(D)>; _2: convert from float to double not important [USE] _1 in _4 = _1 * _3; _1: convert from float to double not important [DEF] Recording new information for _1 = (double) y_7(D); _1: convert from float to double not important gimple_simplified to _10 = _13; Deleting _6 = z_9(D) + _12; Deleting _5 = (double) z_9(D); Deleting _4 = _2 * y_7(D); Deleting _3 = (double) _2; Deleting _1 = (double) y_7(D); __attribute__((noinline)) foo (float x, float y, float z) { float _2; float _10; float _12; float _13; <bb 2> [local count: 1073741824]: _2 = ABS_EXPR <x_8(D)>; _12 = _2 * y_7(D); _13 = z_9(D) + _12; _10 = _13; return _10; } All convert and promotions could be removed. But if change float x to double x, it doesn't work now: 2) mad2.c float foo (double x, float y, float z) { return ( y * fabs (x) + z ); } mad2.c.098t.cunrolli: foo (double x, float y, float z) { double _1; double _2; double _3; double _4; double _5; float _9; <bb 2> [local count: 1073741824]: _1 = (double) y_6(D); _2 = ABS_EXPR <x_7(D)>; _3 = _1 * _2; _4 = (double) z_8(D); _5 = _3 + _4; _9 = (float) _5; return _9; } mad2.c.099t.backprop: [USE] _9 in return _9; [USE] _5 in _9 = (float) _5; _5: convert from float to double not important [DEF] Recording new information for _5 = _3 + _4; _5: convert from float to double not important [USE] _4 in _5 = _3 + _4; _4: convert from float to double not important [DEF] Recording new information for _4 = (double) z_8(D); _4: convert from float to double not important [USE] _3 in _5 = _3 + _4; _3: convert from float to double not important [DEF] Recording new information for _3 = _1 * _2; _3: convert from float to double not important [USE] _2 in _3 = _1 * _2; _2: convert from float to double not important [DEF] Recording new information for _2 = ABS_EXPR <x_7(D)>; _2: convert from float to double not important [USE] _1 in _3 = _1 * _2; _1: convert from float to double not important [DEF] Recording new information for _1 = (double) y_6(D); _1: convert from float to double not important Deleting _4 = (double) z_8(D); Deleting _1 = (double) y_6(D); EMERGENCY DUMP: __attribute__((noinline)) foo (double x, float y, float z) { double _2; double _3; double _5; float _9; <bb 2> [local count: 1073741824]: _2 = ABS_EXPR <x_7(D)>; _3 = _2 * y_6(D); _5 = _3 + z_8(D); _9 = (float) _5; return _9; }
next prev parent reply other threads:[~2020-11-27 6:20 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-22326-4@http.gcc.gnu.org/bugzilla/> 2020-11-17 7:07 ` luoxhu at gcc dot gnu.org 2020-11-17 7:10 ` luoxhu at gcc dot gnu.org 2020-11-17 10:21 ` pinskia at gcc dot gnu.org 2020-11-17 21:56 ` joseph at codesourcery dot com 2020-11-18 15:22 ` segher at gcc dot gnu.org 2020-11-23 8:39 ` luoxhu at gcc dot gnu.org 2020-11-23 8:44 ` luoxhu at gcc dot gnu.org 2020-11-23 12:09 ` rguenther at suse dot de 2020-11-24 10:00 ` rsandifo at gcc dot gnu.org 2020-11-27 6:20 ` luoxhu at gcc dot gnu.org [this message] 2020-11-27 6:27 ` luoxhu at gcc dot gnu.org 2020-11-27 7:12 ` rguenther at suse dot de 2020-11-27 9:24 ` rsandifo at gcc dot gnu.org 2020-11-30 8:31 ` luoxhu at gcc dot gnu.org 2020-12-11 13:49 ` segher at gcc dot gnu.org 2020-12-11 14:24 ` rguenth at gcc dot gnu.org 2020-12-11 17:51 ` segher at gcc dot gnu.org 2020-12-11 19:24 ` rguenther at suse dot de 2020-12-14 7:21 ` luoxhu at gcc dot gnu.org [not found] <bug-22326-6528@http.gcc.gnu.org/bugzilla/> 2006-08-21 6:08 ` pinskia at gcc dot gnu dot org 2007-07-09 6:08 ` pinskia at gcc dot gnu dot org 2005-07-06 15:40 [Bug tree-optimization/22326] New: " pinskia at gcc dot gnu dot org 2005-07-12 20:37 ` [Bug tree-optimization/22326] " pinskia at gcc dot gnu dot org
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