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From: "christophm30 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/105314] [12 Regression] ifcvt regression in noce_try_store_flag_mask
Date: Tue, 26 Apr 2022 00:05:03 +0000	[thread overview]
Message-ID: <bug-105314-4-R6mhfp6Yu4@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-105314-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105314

--- Comment #8 from Christoph Müllner <christophm30 at gmail dot com> ---
Yes, I was wrong in my previous comment.
Jakub's patch is of course right.

The transformation in noce_try_store_flag_mask() does:

  x = cond ? 0 else b  // b may be x

==>

  target = cond ? 0 : -1;  // seqz & neg
  x = target & b;          // and

I was misled by the comment above the function,
which only shows the special case when b equals x.

Probably this is a better comment:

/* Convert "if (test) x = 0 else x = y;" to "x = -(test == 0) & y;"  */

  parent reply	other threads:[~2022-04-26  0:05 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-19 20:19 [Bug tree-optimization/105314] New: " christophm30 at gmail dot com
2022-04-19 20:23 ` [Bug tree-optimization/105314] " christophm30 at gmail dot com
2022-04-20  7:10 ` marxin at gcc dot gnu.org
2022-04-20  7:10 ` marxin at gcc dot gnu.org
2022-04-20  7:49 ` [Bug target/105314] " rguenth at gcc dot gnu.org
2022-04-22  9:48 ` [Bug target/105314] [12 Regression] " pinskia at gcc dot gnu.org
2022-04-25 15:45 ` [Bug rtl-optimization/105314] " jakub at gcc dot gnu.org
2022-04-25 22:34 ` ptomsich at gcc dot gnu.org
2022-04-25 22:40 ` christophm30 at gmail dot com
2022-04-25 22:47 ` ptomsich at gcc dot gnu.org
2022-04-26  0:05 ` christophm30 at gmail dot com [this message]
2022-04-26  8:12 ` cvs-commit at gcc dot gnu.org
2022-04-26  8:13 ` jakub at gcc dot gnu.org
2024-01-26 21:48 ` cvs-commit at gcc dot gnu.org

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