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| author | Richard Sandiford <richard.sandiford@linaro.org> | 2018-05-02 07:40:22 +0000 |
|---|---|---|
| committer | Richard Sandiford <rsandifo@gcc.gnu.org> | 2018-05-02 07:40:22 +0000 |
| commit | 9e4da9b5d5d3d8e14ab1748fafb08c6b9bfcf629 (patch) | |
| tree | cc2d2a65d221c55d054add0a6d8e0909b1c800d6 /gcc | |
| parent | c2e1580cbe2023f9a7ff832d52587825c85c2f6d (diff) | |
| download | gcc-9e4da9b5d5d3d8e14ab1748fafb08c6b9bfcf629.zip gcc-9e4da9b5d5d3d8e14ab1748fafb08c6b9bfcf629.tar.gz gcc-9e4da9b5d5d3d8e14ab1748fafb08c6b9bfcf629.tar.bz2 | |
Tighten early exit in vect_analyze_data_ref_dependence (PR85586)
The problem in this PR was that we didn't consider aliases between
writes in the same strided group. After tightening the early exit
we get the expected abs(step) >= 2 versioning check.
2018-05-02 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
PR tree-optimization/85586
* tree-vect-data-refs.c (vect_analyze_data_ref_dependence): Only
exit early for statements in the same group if the accesses are
not strided.
gcc/testsuite/
PR tree-optimization/85586
* gcc.dg/vect/pr85586.c: New test.
From-SVN: r259822
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/vect/pr85586.c | 43 | ||||
| -rw-r--r-- | gcc/tree-vect-data-refs.c | 6 |
4 files changed, 59 insertions, 2 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 65f76ab..53fa68d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2018-05-02 Richard Sandiford <richard.sandiford@linaro.org> + + PR tree-optimization/85586 + * tree-vect-data-refs.c (vect_analyze_data_ref_dependence): Only + exit early for statements in the same group if the accesses are + not strided. + 2018-05-02 Tom de Vries <tom@codesourcery.com> PR lto/85451 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 465b079..9c93c81 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2018-05-02 Richard Sandiford <richard.sandiford@linaro.org> + + PR tree-optimization/85586 + * gcc.dg/vect/pr85586.c: New test. + 2018-05-01 Marc Glisse <marc.glisse@inria.fr> PR tree-optimization/85143 diff --git a/gcc/testsuite/gcc.dg/vect/pr85586.c b/gcc/testsuite/gcc.dg/vect/pr85586.c new file mode 100644 index 0000000..d6cc92d5 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr85586.c @@ -0,0 +1,43 @@ +#define N 100 + +void __attribute__ ((noipa)) +foo (int *out, int *in, int step) +{ + for (int i = 0; i < N; ++i) + { + out[0] = in[i]; + out[1] = 2; + out += step; + } +} + +int in[N]; +int out[N * 2]; + +int +main (void) +{ + for (int i = 0; i < N; ++i) + { + in[i] = i * (i + 1); + asm volatile ("" ::: "memory"); + } + + foo (out, in, 1); + for (int i = 0; i < N; ++i) + if (out[i] != in[i]) + __builtin_abort (); + if (out[N] != 2) + __builtin_abort (); + + foo (out + N - 1, in, -1); + if (out[0] != in[N - 1]) + __builtin_abort (); + for (int i = 1; i <= N; ++i) + if (out[i] != 2) + __builtin_abort (); + + return 0; +} + +/* { dg-final { scan-tree-dump-times "LOOP VECTORIZED" 1 "vect" { target vect_int } } } */ diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c index df362b0..9608b76 100644 --- a/gcc/tree-vect-data-refs.c +++ b/gcc/tree-vect-data-refs.c @@ -305,9 +305,11 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr, return false; /* We do not have to consider dependences between accesses that belong - to the same group. */ + to the same group, unless the stride could be smaller than the + group size. */ if (GROUP_FIRST_ELEMENT (stmtinfo_a) - && GROUP_FIRST_ELEMENT (stmtinfo_a) == GROUP_FIRST_ELEMENT (stmtinfo_b)) + && GROUP_FIRST_ELEMENT (stmtinfo_a) == GROUP_FIRST_ELEMENT (stmtinfo_b) + && !STMT_VINFO_STRIDED_P (stmtinfo_a)) return false; /* Even if we have an anti-dependence then, as the vectorized loop covers at |