[PATCH][LAA] Fix estimation of number of memchecks

[Silviu Baranga]

Hi,

 

The attached patch fixes the estimation of the number of memchecks.

 

We need to add a runtime memcheck for pair of accesses (x,y) where at least
one of x and y

are writes.

 

Assuming we have w writes and r reads, currently this number is  estimated
as being

w* (w+r-1). This estimation will count (write,write) pairs twice and will
overestimate

the number of checks required.

 

The actual number of memchecks is (r + w - 1) + (r + w - 2) + .. + r which
is equal to

(w^2 + 2wr - w)/2.

 

The patch changes the formula and adds a small test.

 

Please review!

 

Thanks,

Silviu

 

 

 

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