/* { dg-do compile { target { { i?86-*-* x86_64-*-* } && ia32 } } } */ /* { dg-require-effective-target sse2 } */ /* { dg-options "-O2 -fprefetch-loop-arrays -march=athlon -msse2 -mfpmath=sse --param simultaneous-prefetches=100 --param min-insn-to-prefetch-ratio=6 -fdump-tree-aprefetch-details" } */ #define N 1000 #define K 900 double a[N][N]; double test(void) { unsigned i, j; double sum = 0; /* Here, we should use non-temporal prefetch instruction. */ for (i = 0; i < K; i++) for (j = 0; j < K; j++) sum += a[i][j]; /* Here, we should not use non-temporal prefetch instruction, since the value of a[i+10][j] is reused in L2 cache. */ for (i = 0; i < K; i++) for (j = 0; j < K; j++) sum += a[i][j] * a[i + 10][j]; /* Here, we should use non-temporal prefetch instruction, since the value of a[i+100][j] is too far to be reused in L2 cache. */ for (i = 0; i < K; i++) for (j = 0; j < K; j++) sum += a[i][j] * a[i + 100][j]; /* Here, temporal prefetches should be used, since the volume of the memory accesses is smaller than L2 cache. */ for (i = 0; i < 100; i++) for (j = 0; j < 100; j++) sum += a[i][j] * a[i + 100][j]; /* Temporal prefetches should be used here (even though the accesses to a[j][i] are independent, the same cache line is almost always hit every N iterations). */ for (i = 0; i < N; i++) for (j = 0; j < N; j++) sum += a[j][i]; return sum; } /* { dg-final { scan-tree-dump-times "Issued prefetch" 5 "aprefetch" } } */ /* { dg-final { scan-tree-dump-times "Issued nontemporal prefetch" 3 "aprefetch" } } */ /* { dg-final { scan-assembler-times "prefetcht" 5 } } */ /* { dg-final { scan-assembler-times "prefetchnta" 3 } } */ /* { dg-final { cleanup-tree-dump "aprefetch" } } */