[PATCH][X86] Prevent the creation of redundant ops for sadd and ssub with overflow.

[Juergen Ributzka]

Committed in r199976.

On Jan 23, 2014, at 10:25 PM, Nadav Rotem <nrotem at apple.com> wrote:

> On Jan 23, 2014, at 10:22 PM, Juergen Ributzka <juergen at apple.com> wrote:
> 
>> Hi Nadav,
>> 
>> I opened and closed that can of worms very quickly today - thanks for git stash. I first tried to solve it the other way around and remove all INCs and DECs from the backend and only generate ADDs.
>> I think we are currently only generating INCs for EmitTest, LowerXALUO and now also in LowerBRCOND, so it won’t be to difficult to remove them. In the end I didn’t do it, because I didn’t know
>> of an easy way during ISEL that would tell me if it is safe to convert an ADD + 1 to an INC. I fully agree with you and I would also prefer a pass that cleans up afterwards if we want to reclaim the extra
>> bytes we wasted, but I opted for the quick fix instead (for now) ;-)
>> 
> 
> Sounds good.
> 
>> Should I open a bug on bugzilla for this?
> 
> Yes, let’s open a bugzilla. Thank you.

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