61 lines
1.2 KiB
C
61 lines
1.2 KiB
C
/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
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/* { dg-require-effective-target ilp32 } */
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/* { dg-options "-O2 --param min-insn-to-prefetch-ratio=5 -fprefetch-loop-arrays -march=athlon -fdump-tree-aprefetch-details" } */
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/* These are common idioms for writing variable-length arrays at the end
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of structures. We should not deduce anything about the number of iterations
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of the loops from them. */
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struct tail0
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{
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int xxx;
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int yyy[0];
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};
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int loop0 (int n, struct tail0 *x)
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{
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int i, s = 0;
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for (i = 0; i < n; i++)
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s += x->yyy[i];
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return s;
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}
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struct tail1
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{
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int xxx;
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int yyy[1];
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};
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int loop1 (int n, struct tail1 *x)
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{
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int i, s = 0;
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for (i = 0; i < n; i++)
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s += x->yyy[i];
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return s;
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}
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/* It is unlikely that this should be a tail array. We may deduce that most
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likely, the loop iterates about 5 times, and the array is not worth prefetching. */
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struct tail5
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{
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int xxx;
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int yyy[5];
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};
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int loop5 (int n, struct tail5 *x)
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{
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int i, s = 0;
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for (i = 0; i < n; i++)
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s += x->yyy[i];
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return s;
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}
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/* { dg-final { scan-tree-dump-times "Issued prefetch" 2 "aprefetch" } } */
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/* { dg-final { scan-tree-dump-times "Not prefetching" 1 "aprefetch" } } */
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/* { dg-final { cleanup-tree-dump "aprefetch" } } */
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