[Bug tree-optimization/61938] Vectorization not happening .
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61938 Marek Polacek changed: What|Removed |Added Status|WAITING |RESOLVED Resolution|--- |INVALID --- Comment #8 from Marek Polacek --- Nothing to do here.
[Bug tree-optimization/61938] Vectorization not happening .
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61938
--- Comment #7 from Richard Biener ---
(In reply to harmeeksingh from comment #6)
>
> Equivalent code when written by hand where tmp is a intermediate array . The
> compiler
> vectorizes both loops.
>
> int k, i;
> /* vectorize the compares */
> for (i=0; i < arraysize; ++i) {
>tmp[i] = (array[i] == compval);
> }
>
> /* another loop now set the result array */
> for (k=0, i=0; i < arraysize; ++i) {
> if (tmp[i])
> {
>result[k] = i;
>k++;
> }
> }
I only see the first loop vectorized.
typedef long int int64;
typedef int int32;
void foo (int arraysize,
int *__restrict result,
int *__restrict tmp,
int *__restrict selectvector,
int selectelements,
int64 *__restrict array,
int64 compval)
{
int k, i;
/* another loop now set the result array */
for (k=0, i=0; i < arraysize; ++i) {
if (tmp[i])
{
result[k] = i;
k++;
}
}
}
cannot be vectorized exactly because of the said reasons.
[Bug tree-optimization/61938] Vectorization not happening .
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61938
--- Comment #6 from harmeeksingh at gmail dot com ---
Equivalent code when written by hand where tmp is a intermediate array . The
compiler
vectorizes both loops.
int k, i;
/* vectorize the compares */
for (i=0; i < arraysize; ++i) {
tmp[i] = (array[i] == compval);
}
/* another loop now set the result array */
for (k=0, i=0; i < arraysize; ++i) {
if (tmp[i])
{
result[k] = i;
k++;
}
}
[Bug tree-optimization/61938] Vectorization not happening .
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61938 --- Comment #5 from Richard Biener --- The test from comment #3 has exactly the same issue - the store to result[k] cannot be vectorized in any meaningful way.
[Bug tree-optimization/61938] Vectorization not happening .
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61938 --- Comment #4 from Marc Glisse --- Please show what you would like the code to look like after vectorization.
[Bug tree-optimization/61938] Vectorization not happening .
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61938
--- Comment #3 from harmeeksingh at gmail dot com ---
#include
#define VEC 1024
typedef long int int64;
typedef int int32;
void foo (int arraysize,
int *__restrict result,
int *__restrict selectvector,
int selectelements,
int64 *__restrict array,
int64 compval)
{
int k, i;
for (k =0,i=0; i < arraysize; ++i) {
result[k] = i; k += (array[i] == compval);
}
}
main()
{
int result[VEC];
int selectvector[VEC];
int selectelements;
int64 array[VEC];
int k, i;
foo(VEC, result, selectvector, VEC, array, 1);
}
Even the above does not vectorize
gcc -fPIC -shared -DCLS=64 -ffast-math -mfpmath=sse -mmmx -msse -msse2
-ftree-vectorize -ftree-vectorizer-verbose=7 -O3 -march=native /tmp/x.c -o
/tmp/x
Analyzing loop at /tmp/x.c:17
17: not vectorized: data ref analysis failed *D.2502_9 = i_27;
/tmp/x.c:9: note: vectorized 0 loops in function.
[Bug tree-optimization/61938] Vectorization not happening .
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61938 Richard Biener changed: What|Removed |Added Status|UNCONFIRMED |WAITING Last reconfirmed||2014-07-29 Ever confirmed|0 |1 --- Comment #2 from Richard Biener --- The issue is the store to result[k] where k is not an affine induction variable. This is a "distribute" store (similar to a "gather" load). I see no sensible way of vectorizing this, do you?
[Bug tree-optimization/61938] Vectorization not happening .
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61938 --- Comment #1 from Andrew Pinski --- array[selectvector[i]] is not handled.
