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From: "oleg.endo@t-online.de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/49263] SH Target: underutilized "TST #imm, R0" instruction Date: Sun, 20 Nov 2011 14:20:00 -0000 [thread overview] Message-ID: <bug-49263-4-reXq8hpaob@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-49263-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49263 --- Comment #14 from Oleg Endo <oleg.endo@t-online.de> 2011-11-20 13:04:39 UTC --- With trunk rev 181517 I have observed the following problem, which happens when compiling for -m2*, -m3*, -m4* and -Os: The function compiled with -m2 -Os int test_int64_lowword (long long* x) { return *x & 0xFFFFFFFF ? -20 : -40; } results in the following code: mov #0,r2 ! 42 movsi_i/3 [length = 2] tst r2,r2 ! 44 cmpeqsi_t/1 [length = 2] bf.s .L4 ! 45 branch_false [length = 2] mov.l @(4,r4),r3 ! 12 movsi_i/5 [length = 2] tst r3,r3 ! 46 cmpeqsi_t/1 [length = 2] .L4: bt .L3 ! 14 branch_true [length = 2] mov #-20,r0 ! 4 movsi_i/3 [length = 2] rts nop ! 52 *return_i [length = 4] .L3: rts ! 54 *return_i [length = 2] mov #-40,r0 ! 5 movsi_i/3 [length = 2] When compiled with -O1 or -O2 the high word test is completely eliminated correctly: mov.l @(4,r4),r1 ! 10 movsi_i/5 [length = 2] tst r1,r1 ! 17 cmpeqsi_t/1 [length = 2] bt .L4 ! 18 branch_true [length = 2] mov #-20,r0 ! 4 movsi_i/3 [length = 2] rts nop ! 50 *return_i [length = 4] .L4: rts ! 52 *return_i [length = 2] mov #-40,r0 ! 5 movsi_i/3 [length = 2] I'm not sure whether this is actually related to this PR, but have noticed it with the test cases of this PR. It seems only to happen for comparison-like insns. If I remember correctly, this problem did not exist when I started working on this PR.
next prev parent reply other threads:[~2011-11-20 13:04 UTC|newest] Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-06-01 20:17 [Bug target/49263] New: " oleg.endo@t-online.de 2011-06-01 20:42 ` [Bug target/49263] " oleg.endo@t-online.de 2011-06-12 23:12 ` kkojima at gcc dot gnu.org 2011-06-19 16:42 ` oleg.endo@t-online.de 2011-06-22 22:34 ` kkojima at gcc dot gnu.org 2011-06-26 22:31 ` oleg.endo@t-online.de 2011-06-27 5:15 ` kkojima at gcc dot gnu.org 2011-10-09 23:35 ` oleg.endo@t-online.de 2011-10-10 1:32 ` kkojima at gcc dot gnu.org 2011-10-10 23:48 ` oleg.endo@t-online.de 2011-10-11 1:47 ` kkojima at gcc dot gnu.org 2011-10-13 22:55 ` oleg.endo@t-online.de 2011-10-14 23:06 ` kkojima at gcc dot gnu.org 2011-10-15 2:33 ` kkojima at gcc dot gnu.org 2011-11-20 14:20 ` oleg.endo@t-online.de [this message] 2011-12-29 1:09 ` oleg.endo@t-online.de 2012-02-26 16:28 ` olegendo at gcc dot gnu.org 2012-02-26 23:29 ` olegendo at gcc dot gnu.org 2012-08-27 19:52 ` olegendo at gcc dot gnu.org 2012-10-28 22:02 ` olegendo at gcc dot gnu.org 2012-10-31 13:47 ` olegendo at gcc dot gnu.org 2013-12-08 13:47 ` olegendo at gcc dot gnu.org 2013-12-17 12:37 ` olegendo at gcc dot gnu.org 2014-12-30 18:45 ` olegendo at gcc dot gnu.org 2015-01-24 13:05 ` olegendo at gcc dot gnu.org 2015-01-26 23:57 ` olegendo at gcc dot gnu.org 2023-05-12 11:46 ` klepikov.alex+bugs at gmail dot com 2023-05-23 12:34 ` klepikov.alex+bugs at gmail dot com 2023-05-23 12:35 ` klepikov.alex+bugs at gmail dot com 2023-05-23 19:05 ` olegendo at gcc dot gnu.org 2023-05-24 11:40 ` klepikov.alex+bugs at gmail dot com 2023-05-24 11:57 ` olegendo at gcc dot gnu.org 2023-05-24 13:34 ` klepikov.alex+bugs at gmail dot com 2023-05-24 15:00 ` olegendo at gcc dot gnu.org 2023-05-25 17:53 ` klepikov.alex+bugs at gmail dot com 2023-05-25 21:32 ` olegendo at gcc dot gnu.org 2023-05-26 12:03 ` klepikov.alex+bugs at gmail dot com 2023-05-26 17:44 ` olegendo at gcc dot gnu.org 2023-05-28 10:24 ` klepikov.alex+bugs at gmail dot com 2023-05-28 10:48 ` olegendo at gcc dot gnu.org 2023-05-29 14:54 ` klepikov.alex+bugs at gmail dot com 2023-05-30 1:48 ` egallager at gcc dot gnu.org 2023-05-30 1:56 ` olegendo at gcc dot gnu.org 2023-05-30 12:42 ` klepikov.alex+bugs at gmail dot com 2023-05-30 19:57 ` olegendo at gcc dot gnu.org 2023-05-30 20:00 ` olegendo at gcc dot gnu.org
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