https://bugs.llvm.org/show_bug.cgi?id=52126
Bug ID: 52126
Summary: SLP: missed vectorization due to cost model (benchmark
from SPECFP 2006)
Product: libraries
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: enhancement
Priority: P
Component: Scalar Optimizations
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected]
433.milc
typedef struct {
double real;
double imag;
} complex;
typedef struct {
complex e[3][3];
} su3_matrix;
#define CSUM(a, b) \
{ \
(a).real += (b).real; \
(a).imag += (b).imag; \
}
#define CMUL(a, b, c) \
{ \
(c).real = (a).real * (b).real - (a).imag * (b).imag; \
(c).imag = (a).real * (b).imag + (a).imag * (b).real; \
}
void mult_su3_nn2(su3_matrix *a, su3_matrix *b, su3_matrix *c) {
int i, j, k;
complex x, y;
for (i = 0; i < 3; i++)
for (j = 0; j < 3; j++) {
x.real = x.imag = 0.0;
for (k = 0; k < 3; k++) {
CMUL(a->e[i][k], b->e[k][j], y);
CSUM(x, y);
}
c->e[i][j] = x;
}
}
Flags: -Ofast -mavx
https://godbolt.org/z/b6nq5sKaW
example.cpp:10:5: remark: the cost-model indicates that vectorization is not
beneficial [-Rpass-missed=loop-vectorize]
for(i=0;i<3;i++)
^
example.cpp:10:5: remark: the cost-model indicates that interleaving is not
beneficial [-Rpass-missed=loop-vectorize]
GCC/ICC vectorizes mult_su3_nn_unrolled. LLVM does not vectorize it with
AVX/AVX, only with -AVX512 (but does not use vaddsubpd as GCC and ICC do; GCC
recently added pattern detection for addsub to SLP vectorizer)
--
You are receiving this mail because:
You are on the CC list for the bug._______________________________________________
llvm-bugs mailing list
[email protected]
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
