[PATCH] LSR: Account for 2 foldable register in addressing mode if the target allows that.

[Andrew Trick]

On May 31, 2013, at 9:35 AM, Quentin Colombet <qcolombet at apple.com> wrote:

> <Mail Attachment>
> On May 29, 2013, at 12:48 PM, Quentin Colombet <qcolombet at apple.com> wrote:
> 
>> Hi,
>> 
>> Here is a patch that modifies how the formulae are rated in Loop Strength Reduce.
>> Namely, this patch checks if the target allows to fold more that one register in the addressing mode and if yes, adjusts the cost accordingly.
>> 
>> Prior to this patch, reg1 + scale * reg2 accesses were artificially preferred to reg1 + reg2 accesses. Indeed, the cost model wrongly assumed that reg1 + reg2 needs a temporary register for the computation, whereas it was correctly estimated for reg1 + scale * reg2.
>> 
>> This patch fixes that.
>> 
>> Thanks for the reviews.

LGTM.

Thanks!

-Andy
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