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From: "mjr19 at cam dot ac.uk" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/114324] [13/14 Regression] AVX2 vectorisation performance regression with gfortran 13/14
Date: Fri, 15 Mar 2024 20:06:58 +0000	[thread overview]
Message-ID: <bug-114324-4-6Exr3o77CH@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-114324-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114324

--- Comment #4 from mjr19 at cam dot ac.uk ---
Created attachment 57713
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57713&action=edit
Second testcase, very similar to first

Thank you for looking into this. The real code in question has more than one
loop which suffers a slow-down with gfortran 13/14 when compared to 12, and I
suspect it is the same underlying issue in all cases.

I attach another test case, which seems very similar. The odd logic surrounding
the initialisation of ci is to replicate the fact that in the real code the
sign of ci depends on an argument which I have dropped, and so the compiler
cannot optimise it away completely.

For this case, gfortran 12 and ifort produce very similar performance, gfortran
13 is over 20% slower, and ifx slower still.

  parent reply	other threads:[~2024-03-15 20:07 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-13 12:52 [Bug fortran/114324] New: " mjr19 at cam dot ac.uk
2024-03-13 19:45 ` [Bug tree-optimization/114324] [13/14 Regression] " pinskia at gcc dot gnu.org
2024-03-14  8:32 ` rguenth at gcc dot gnu.org
2024-03-14  8:32 ` rguenth at gcc dot gnu.org
2024-03-14 10:37 ` rguenth at gcc dot gnu.org
2024-03-15 20:06 ` mjr19 at cam dot ac.uk [this message]
2024-05-01 13:21 ` [Bug tree-optimization/114324] [13/14/15 " mjr19 at cam dot ac.uk
2024-05-21  9:19 ` jakub at gcc dot gnu.org

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