From: rsandifo Date: Thu, 20 Sep 2018 12:58:23 +0000 (+0000) Subject: Fix PEELING_FOR_NITERS calculation (PR 87288) X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c333203af43fc99051f552e7ecf722a48012eed9;p=thirdparty%2Fgcc.git Fix PEELING_FOR_NITERS calculation (PR 87288) PEELING_FOR_GAPS now means "peel one iteration for the epilogue", in much the same way that PEELING_FOR_ALIGNMENT > 0 means "peel that number of iterations for the prologue". We weren't taking this into account when deciding whether we needed to peel further scalar iterations beyond the iterations for "gaps" and "alignment". Only the first test failed before the patch. The other two are just for completeness. 2018-09-20 Richard Sandiford gcc/ PR tree-optimization/87288 * tree-vect-loop.c (vect_analyze_loop_2): Take PEELING_FOR_GAPS into account when determining PEELING_FOR_NITERS. gcc/testsuite/ PR tree-optimization/87288 * gcc.dg/vect/pr87288-1.c: New test. * gcc.dg/vect/pr87288-2.c: Likewise, * gcc.dg/vect/pr87288-3.c: Likewise. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@264440 138bc75d-0d04-0410-961f-82ee72b054a4 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index af5fddf10ce8..f4002840a8cf 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2018-09-20 Richard Sandiford + + PR tree-optimization/87288 + * tree-vect-loop.c (vect_analyze_loop_2): Take PEELING_FOR_GAPS + into account when determining PEELING_FOR_NITERS. + 2018-09-20 Richard Sandiford PR tree-optimization/86877 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index ade95dbb5c90..c7c8e90b27c5 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,10 @@ +2018-09-20 Richard Sandiford + + PR tree-optimization/87288 + * gcc.dg/vect/pr87288-1.c: New test. + * gcc.dg/vect/pr87288-2.c: Likewise, + * gcc.dg/vect/pr87288-3.c: Likewise. + 2018-09-20 Richard Sandiford PR tree-optimization/86877 diff --git a/gcc/testsuite/gcc.dg/vect/pr87288-1.c b/gcc/testsuite/gcc.dg/vect/pr87288-1.c new file mode 100644 index 000000000000..0d0a70dff6f2 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr87288-1.c @@ -0,0 +1,49 @@ +#include "tree-vect.h" + +#define N (VECTOR_BITS / 32) +#define MAX_COUNT 4 + +void __attribute__ ((noipa)) +run (int *restrict a, int *restrict b, int count) +{ + for (int i = 0; i < count * N; ++i) + { + a[i * 2] = b[i * 2] + count; + a[i * 2 + 1] = count; + } +} + +void __attribute__ ((noipa)) +check (int *restrict a, int count) +{ + for (int i = 0; i < count * N; ++i) + if (a[i * 2] != i * 41 + count || a[i * 2 + 1] != count) + __builtin_abort (); + if (a[count * 2 * N] != 999) + __builtin_abort (); +} + +int a[N * MAX_COUNT * 2 + 1], b[N * MAX_COUNT * 2]; + +int +main (void) +{ + check_vect (); + + for (int i = 0; i < N * MAX_COUNT; ++i) + { + b[i * 2] = i * 41; + asm volatile ("" ::: "memory"); + } + + for (int i = 0; i <= MAX_COUNT; ++i) + { + a[i * 2 * N] = 999; + run (a, b, i); + check (a, i); + } + + return 0; +} + +/* { dg-final { scan-tree-dump-times {LOOP VECTORIZED} 1 "vect" { target { { vect_int && vect_perm } && vect_element_align } } } } */ diff --git a/gcc/testsuite/gcc.dg/vect/pr87288-2.c b/gcc/testsuite/gcc.dg/vect/pr87288-2.c new file mode 100644 index 000000000000..e9ff9a0be7c0 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr87288-2.c @@ -0,0 +1,64 @@ +#include "tree-vect.h" + +#define N (VECTOR_BITS / 32) +#define MAX_COUNT 4 + +#define RUN_COUNT(COUNT) \ + void __attribute__ ((noipa)) \ + run_##COUNT (int *restrict a, int *restrict b) \ + { \ + for (int i = 0; i < N * COUNT; ++i) \ + { \ + a[i * 2] = b[i * 2] + COUNT; \ + a[i * 2 + 1] = COUNT; \ + } \ + } + +RUN_COUNT (1) +RUN_COUNT (2) +RUN_COUNT (3) +RUN_COUNT (4) + +void __attribute__ ((noipa)) +check (int *restrict a, int count) +{ + for (int i = 0; i < count * N; ++i) + if (a[i * 2] != i * 41 + count || a[i * 2 + 1] != count) + __builtin_abort (); + if (a[count * 2 * N] != 999) + __builtin_abort (); +} + +int a[N * MAX_COUNT * 2 + 1], b[N * MAX_COUNT * 2]; + +int +main (void) +{ + check_vect (); + + for (int i = 0; i < N * MAX_COUNT; ++i) + { + b[i * 2] = i * 41; + asm volatile ("" ::: "memory"); + } + + a[N * 2] = 999; + run_1 (a, b); + check (a, 1); + + a[N * 4] = 999; + run_2 (a, b); + check (a, 2); + + a[N * 6] = 999; + run_3 (a, b); + check (a, 3); + + a[N * 8] = 999; + run_4 (a, b); + check (a, 4); + + return 0; +} + +/* { dg-final { scan-tree-dump {LOOP VECTORIZED} "vect" { target { { vect_int && vect_perm } && vect_element_align } } } } */ diff --git a/gcc/testsuite/gcc.dg/vect/pr87288-3.c b/gcc/testsuite/gcc.dg/vect/pr87288-3.c new file mode 100644 index 000000000000..23f574ccb532 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr87288-3.c @@ -0,0 +1,64 @@ +#include "tree-vect.h" + +#define N (VECTOR_BITS / 32) +#define MAX_COUNT 4 + +#define RUN_COUNT(COUNT) \ + void __attribute__ ((noipa)) \ + run_##COUNT (int *restrict a, int *restrict b) \ + { \ + for (int i = 0; i < N * COUNT + 1; ++i) \ + { \ + a[i * 2] = b[i * 2] + COUNT; \ + a[i * 2 + 1] = COUNT; \ + } \ + } + +RUN_COUNT (1) +RUN_COUNT (2) +RUN_COUNT (3) +RUN_COUNT (4) + +void __attribute__ ((noipa)) +check (int *restrict a, int count) +{ + for (int i = 0; i < count * N + 1; ++i) + if (a[i * 2] != i * 41 + count || a[i * 2 + 1] != count) + __builtin_abort (); + if (a[count * 2 * N + 2] != 999) + __builtin_abort (); +} + +int a[N * MAX_COUNT * 2 + 3], b[N * MAX_COUNT * 2 + 2]; + +int +main (void) +{ + check_vect (); + + for (int i = 0; i < N * MAX_COUNT + 1; ++i) + { + b[i * 2] = i * 41; + asm volatile ("" ::: "memory"); + } + + a[N * 2 + 2] = 999; + run_1 (a, b); + check (a, 1); + + a[N * 4 + 2] = 999; + run_2 (a, b); + check (a, 2); + + a[N * 6 + 2] = 999; + run_3 (a, b); + check (a, 3); + + a[N * 8 + 2] = 999; + run_4 (a, b); + check (a, 4); + + return 0; +} + +/* { dg-final { scan-tree-dump {LOOP VECTORIZED} "vect" { target { { vect_int && vect_perm } && vect_element_align } } } } */ diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index 70e9157646fd..fdac10bab5ac 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -2074,14 +2074,22 @@ start_over: /* The main loop handles all iterations. */ LOOP_VINFO_PEELING_FOR_NITER (loop_vinfo) = false; else if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo) - && LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo) > 0) + && LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo) >= 0) { - if (!multiple_p (LOOP_VINFO_INT_NITERS (loop_vinfo) - - LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo), + /* Work out the (constant) number of iterations that need to be + peeled for reasons other than niters. */ + unsigned int peel_niter = LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo); + if (LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo)) + peel_niter += 1; + if (!multiple_p (LOOP_VINFO_INT_NITERS (loop_vinfo) - peel_niter, LOOP_VINFO_VECT_FACTOR (loop_vinfo))) LOOP_VINFO_PEELING_FOR_NITER (loop_vinfo) = true; } else if (LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo) + /* ??? When peeling for gaps but not alignment, we could + try to check whether the (variable) niters is known to be + VF * N + 1. That's something of a niche case though. */ + || LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo) || !LOOP_VINFO_VECT_FACTOR (loop_vinfo).is_constant (&const_vf) || ((tree_ctz (LOOP_VINFO_NITERS (loop_vinfo)) < (unsigned) exact_log2 (const_vf))