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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/99863] [10/11 Regression] wrong code with -O -fno-tree-forwprop -mno-sse2
Date: Thu, 01 Apr 2021 09:14:11 +0000	[thread overview]
Message-ID: <bug-99863-4-f86YY5bq5v@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-99863-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99863

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Also time to fix this stupid veclower behavior:

   _7 = (unsigned int) _14;
   _5 = {_7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7};
-  v512u32_0_16 = _5 * v512u32_0_15(D);
+  _53 = {_7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7};
+  _54 = BIT_FIELD_REF <_53, 32, 0>;
+  _55 = BIT_FIELD_REF <v512u32_0_15(D), 32, 0>;
+  _56 = _54 * _55;
+  _57 = {_7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7};
+  _58 = BIT_FIELD_REF <_57, 32, 32>;
+  _59 = BIT_FIELD_REF <v512u32_0_15(D), 32, 32>;
+  _60 = _58 * _59;
...

instead of

   _5 = {_7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7};
-  v512u32_0_16 = _5 * v512u32_0_15(D);
   _54 = BIT_FIELD_REF <_5, 32, 0>;
...

or even better

   _5 = {_7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7, _7};
-  v512u32_0_16 = _5 * v512u32_0_15(D);
+  _55 = BIT_FIELD_REF <v512u32_0_15(D), 32, 0>;
+  _56 = _7 * _55;

it's all "fixed" later by CSE of course.

The error might be involving the clever handling of

-  v256u8_r_17 = _8 + _19;
+  _117 = BIT_FIELD_REF <_8, 64, 0>;
+  _118 = BIT_FIELD_REF <_19, 64, 0>;
+  _119 = _117 ^ _118;
+  _120 = _118 & 9187201950435737471;
+  _121 = _117 & 9187201950435737471;
+  _122 = _119 & 9259542123273814144;
+  _123 = _120 + _121;
+  _124 = _122 ^ _123;
+  _125 = BIT_FIELD_REF <_8, 64, 64>;
+  _126 = BIT_FIELD_REF <_19, 64, 64>;
...
+  _149 = {_124, _132, _140, _148};
+  _150 = VIEW_CONVERT_EXPR<v256u8>(_149);
+  v256u8_r_17 = _150;

it's enough to -fdisable-tree-forwprop4 (forwprop after veclower) to make
the problem show up so it might be as well an RTL optimization issue.

  parent reply	other threads:[~2021-04-01  9:14 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-01  8:44 [Bug target/99863] New: " zsojka at seznam dot cz
2021-04-01  9:01 ` [Bug target/99863] " rguenth at gcc dot gnu.org
2021-04-01  9:14 ` rguenth at gcc dot gnu.org [this message]
2021-04-01  9:58 ` rguenth at gcc dot gnu.org
2021-04-01 10:02 ` [Bug target/99863] [10/11 Regression] wrong code with -O -fno-tree-forwprop -mno-sse2 since r10-7268-g529ea7d9596b26ba marxin at gcc dot gnu.org
2021-04-01 10:24 ` rguenth at gcc dot gnu.org
2021-04-01 10:45 ` [Bug rtl-optimization/99863] " rguenth at gcc dot gnu.org
2021-04-01 10:47 ` cvs-commit at gcc dot gnu.org
2021-04-01 11:16 ` ebotcazou at gcc dot gnu.org
2021-04-01 11:28 ` ebotcazou at gcc dot gnu.org
2021-04-01 12:26 ` jakub at gcc dot gnu.org
2021-04-01 12:45 ` rguenther at suse dot de
2021-04-01 13:01 ` jakub at gcc dot gnu.org
2021-04-01 13:23 ` jakub at gcc dot gnu.org
2021-04-01 13:27 ` jakub at gcc dot gnu.org
2021-04-01 13:32 ` rguenther at suse dot de
2021-04-01 13:35 ` jakub at gcc dot gnu.org
2021-04-01 13:54 ` jakub at gcc dot gnu.org
2021-04-03  8:07 ` cvs-commit at gcc dot gnu.org
2021-04-03  8:16 ` [Bug rtl-optimization/99863] [10 " jakub at gcc dot gnu.org
2021-04-08 12:02 ` rguenth at gcc dot gnu.org
2021-04-20  9:45 ` cvs-commit at gcc dot gnu.org
2021-04-20  9:50 ` jakub at gcc dot gnu.org
2021-04-20 23:34 ` cvs-commit at gcc dot gnu.org
2021-04-22 16:52 ` cvs-commit at gcc dot gnu.org

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