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Re: Fix twolf -funroll-loops -O3 miscompilation (a semi-latent web.c bug)

From: Eric Botcazou <ebotcazou at adacore dot com>
To: Steven Bosscher <stevenb dot gcc at gmail dot com>
Cc: gcc-patches at gcc dot gnu dot org, Dominique Dhumieres <dominiq at lps dot ens dot fr>, bonzini at gnu dot org, hubicka at ucw dot cz
Date: Mon, 19 Nov 2012 22:27:41 +0100
Subject: Re: Fix twolf -funroll-loops -O3 miscompilation (a semi-latent web.c bug)
References: <20121118231540.726263BABA@mailhost.lps.ens.fr> <2642387.neydDsRiAt@polaris> <CABu31nPfTSwrMvmk1BHmcz5iR=oO5CGz1q0eYAx9ezbhLZXiLA@mail.gmail.com>

> Thanks for this reduced test case, that's saving me a lot of work!

You're welcome.

> Can you please try and see if the following C test case also fails?

Yup, with the same compilation options, there are the same dreadful lines

	ld	[%g0+0], %fn

in the assembly file, which translates into (mem:SF (const_int 0 [0])) in the 
RTL dumps.  And the executable does segfault at runtime.

-- 
Eric Botcazou

References:
- Re: Fix twolf -funroll-loops -O3 miscompilation (a semi-latent web.c bug)
  - From: Dominique Dhumieres
- Re: Fix twolf -funroll-loops -O3 miscompilation (a semi-latent web.c bug)
  - From: Eric Botcazou
- Re: Fix twolf -funroll-loops -O3 miscompilation (a semi-latent web.c bug)
  - From: Steven Bosscher

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