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Re: [PATCH] Optimize 'a ' as single char string too

From: Toon Moene <toon at moene dot org>
To: Jakub Jelinek <jakub at redhat dot com>
Cc: gcc-patches at gcc dot gnu dot org, fortran at gcc dot gnu dot org
Date: Tue, 13 Jul 2010 22:37:53 +0200
Subject: Re: [PATCH] Optimize 'a ' as single char string too
References: <20100713203346.GF20208@tyan-ft48-01.lab.bos.redhat.com>

Jakub Jelinek wrote:

On:

subroutine foo (c)
  character :: c
  if (c .eq. 'a') call abort
  if (c .eq. 'ab') call abort
  if (c .eq. 'a ') call abort
end subroutine

only the first test is optimized into c == 'a' comparison, the other
two call _gfortran_compare_string.

Strictly speaking, a single character (character string of length 1) can never be equal to 'ab', so that could be removed too - but that's probably a case for the Fortran Frontend ...

--
Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands
At home: http://moene.org/~toon/; weather: http://moene.org/~hirlam/
Progress of GNU Fortran: http://gcc.gnu.org/gcc-4.5/changes.html#Fortran

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References:
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  - From: Jakub Jelinek

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