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From: Harald Anlauf <anlauf@gmx.de>
To: Harald Anlauf <anlauf@gmx.de>
Cc: Jerry DeLisle <jvdelisle@charter.net>, fortran <fortran@gcc.gnu.org>,
 gcc-patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] PR libfortran/99218 - [8/9/10/11 Regression] matmul on
 temporary array accesses invalid memory
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Date: Fri, 5 Mar 2021 20:56:17 +0100
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Dear all,

I finally figured out that the array dimensions simply need to be
large enough to get invalid memory accesses that actual lead to a
crash.

I will commit the following testcase along with the fix to libfortran:


! { dg-do run }
! PR libfortran/99218 - matmul on temporary array accesses invalid memory

program p
  implicit none
  integer, parameter :: nState = 300000
  integer, parameter :: nCon = 1
  real,    parameter :: ZERO = 0.0
  real :: G(nCon,nState) = ZERO
  real :: H(nState,nCon) = ZERO
  real :: lambda(nCon)   = ZERO
  real :: f(nState)      = ZERO
  f = matmul (transpose (G), lambda)
  if (f(1) /= ZERO) stop 1
end program


Cheers,
Harald