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Re: [Patch] sext_hwi: Avoid left shift of negative value undefined behaviour


On 2015.08.13 at 15:40 +0200, Marek Polacek wrote:
> On Thu, Aug 13, 2015 at 01:11:53PM +0200, Richard Biener wrote:
> > Rather ubsan should not complain about implementation defined behavior (or
> > should separate those cases out with a different switch compared to undefined
> > behavior).
> 
> I think ubsan doesn't complain about implementation-defined behavior.  It seems
> to me that in this thread it only (rightfully) complained about left-shifting of
> negative value. 

There are two issues in the same location:

1) gcc/hwint.h:250:19: runtime error: left shift of 8589934588 by 32
places cannot be represented in type 'long int'

2) left-shifting of negative values


-- 
Markus


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