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Subject: [Bug fortran/50564] [4.7 Regression] Front-end optimization - ICE with FORALL
Date: Sat, 08 Oct 2011 21:41:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50564

--- Comment #4 from Thomas Koenig <tkoenig at gcc dot gnu.org> 2011-10-08 21:41:11 UTC ---
FORALL sucks rocks through a straw.

We cannot use the usual front-end optimization within forall, because

  forall(iTime=1:2)
     tmp = dble(iTime)
     timeSteps(iTime)=ratio**(tmp-0.5d0)-ratio**(tmp-1.5d0)
  end forall

doesn't work (gfortran correctly warns about multiple assignments to tmp).

So, the best method is to disable front-end optimization within
a forall loop.

I assume the same holds for DO CONCURRENT.