Vectorizer fails to handle this:
------------------------------------------------------------
#define NUMPOINTS 50000
#define align(x) __attribute__((align(x)))
typedef float align(16) MATRIX[3][3];
static float points[NUMPOINTS][4];
static align(16) float opoints[NUMPOINTS][4];
static bool flags[NUMPOINTS];
static MATRIX gmatrix;
void RotateVectors (void)
{
int i, r;
for (r = 0; r < 4; r++)
{
for (i = 0; i < NUMPOINTS; i++)
{
opoints[i][0] = gmatrix[0][0] * points[i][0]
+ gmatrix[0][1] * points[i][1]
+ gmatrix[0][2] * points[i][2];
opoints[i][1] = gmatrix[1][0] * points[i][0]
+ gmatrix[1][1] * points[i][1]
+ gmatrix[1][2] * points[i][2];
opoints[i][2] = gmatrix[2][0] * points[i][0]
+ gmatrix[2][1] * points[i][1]
+ gmatrix[2][2] * points[i][2];
flags[i] = true;
}
}
}
------------------------------------------------------------
loop at bench.cc:52: not vectorized: complicated access pattern.
loop at bench.cc:52: bad data access.
--
Summary: vectorizer failed for vector matrix multiplication
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: enhancement
Priority: P2
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: giovannibajo at libero dot it
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18438
