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Re: [PATCH] Fix PR48182


On Fri, Apr 05, 2013 at 02:21:57PM -0600, Jeff Law wrote:
> On 04/05/2013 09:22 AM, Marek Polacek wrote:
> >This patch prevents segfault when using --param min-crossjump-insns=0.
> >What can happen in that case is that flow_find_cross_jump returns 0,
> >thus nmatch is 0, then
> >nmatch < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS)
> >doesn't hold, thus we continue, but we segfault later on when
> >doing split_block.  I think it's better to just bail out in that
> >case; moreover setting min-crossjump-insns to 0 isn't very common...
> >
> >Regtested/bootstrapped on x86_64-linux, ok for trunk/4.8?
> >
> >2013-04-05  Marek Polacek  <polacek@redhat.com>
> >
> >	PR rtl-optimization/48182
> >	* cfgcleanup.c (try_crossjump_to_edge): Bail out if
> >	PARAM_MIN_CROSSJUMP_INSNS is 0.
> >
> >	* gcc.dg/pr48182.c: New test.
> OK for the trunk.  Release manager's decision for 4.8.

Wouldn't it be better to change params.def to instead say:
     5, 1, 0)
Because with the cfgcleanup.c change, --param min-crossjump-insns=0
is handled as =infinity rather than something smaller than 0.

	Jakub


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