From 48df3fa66cf86d6da365a459aae689bb937128a3 Mon Sep 17 00:00:00 2001 From: Ira Rosen Date: Thu, 26 May 2011 07:50:09 +0000 Subject: [PATCH] re PR tree-optimization/49038 (-ftree-vectorise introduces reads past end of array) PR tree-optimization/49038 * tree-vect-loop-manip.c (vect_generate_tmps_on_preheader): Ensure at least one epilogue iteration if required by data accesses with gaps. * tree-vectorizer.h (struct _loop_vec_info): Add new field to mark loops that require peeling for gaps. * tree-vect-loop.c (new_loop_vec_info): Initialize new field. (vect_get_known_peeling_cost): Take peeling for gaps into account. (vect_transform_loop): Generate epilogue if required by data access with gaps. * tree-vect-data-refs.c (vect_analyze_group_access): Mark the loop as requiring an epilogue if there are gaps in the end of the strided group. From-SVN: r174265 --- gcc/ChangeLog | 17 +++ gcc/testsuite/ChangeLog | 6 + gcc/testsuite/gcc.dg/vect/pr49038.c | 38 +++++++ .../vect/vect-strided-u8-i8-gap4-unknown.c | 103 ++++++++++++++++++ gcc/tree-vect-data-refs.c | 24 +++- gcc/tree-vect-loop-manip.c | 34 +++++- gcc/tree-vect-loop.c | 8 +- gcc/tree-vectorizer.h | 6 + 8 files changed, 232 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/vect/pr49038.c create mode 100644 gcc/testsuite/gcc.dg/vect/vect-strided-u8-i8-gap4-unknown.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index ce1b46448bd..3e348cca419 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,20 @@ +2011-05-26 Ira Rosen + + PR tree-optimization/49038 + * tree-vect-loop-manip.c (vect_generate_tmps_on_preheader): + Ensure at least one epilogue iteration if required by data + accesses with gaps. + * tree-vectorizer.h (struct _loop_vec_info): Add new field + to mark loops that require peeling for gaps. + * tree-vect-loop.c (new_loop_vec_info): Initialize new field. + (vect_get_known_peeling_cost): Take peeling for gaps into + account. + (vect_transform_loop): Generate epilogue if required by data + access with gaps. + * tree-vect-data-refs.c (vect_analyze_group_access): Mark the + loop as requiring an epilogue if there are gaps in the end of + the strided group. + 2011-05-25 Ian Lance Taylor * godump.c (go_format_type): Output the first field with a usable diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 4703f568aac..44ab3d0bebd 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2011-05-26 Ira Rosen + + PR tree-optimization/49038 + * gcc.dg/vect/vect-strided-u8-i8-gap4-unknown.c: New test. + * gcc.dg/vect/pr49038.c: New test. + 2011-05-26 Fabien Chêne * g++.dg/init/pr25811-3.C: New. * g++.dg/init/pr25811-4.C: New. diff --git a/gcc/testsuite/gcc.dg/vect/pr49038.c b/gcc/testsuite/gcc.dg/vect/pr49038.c new file mode 100644 index 00000000000..ab440a38996 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr49038.c @@ -0,0 +1,38 @@ +#include +#include + +#define COUNT 320 +#define MMAP_SIZE 0x10000 +#define ADDRESS 0x1122000000 +#define TYPE unsigned short + +void __attribute__((noinline)) +foo (TYPE *__restrict a, TYPE *__restrict b) +{ + int n; + + for (n = 0; n < COUNT; n++) + a[n] = b[n * 2]; +} + +int +main (void) +{ + void *x; + size_t b_offset; + + x = mmap ((void *) ADDRESS, MMAP_SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (x == MAP_FAILED) + { + perror ("mmap"); + return 1; + } + + b_offset = MMAP_SIZE - (2 * COUNT - 1) * sizeof (TYPE); + foo ((unsigned short *) x, + (unsigned short *) ((char *) x + b_offset)); + return 0; +} + +/* { dg-final { cleanup-tree-dump "vect" } } */ diff --git a/gcc/testsuite/gcc.dg/vect/vect-strided-u8-i8-gap4-unknown.c b/gcc/testsuite/gcc.dg/vect/vect-strided-u8-i8-gap4-unknown.c new file mode 100644 index 00000000000..a13bc98ba05 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/vect-strided-u8-i8-gap4-unknown.c @@ -0,0 +1,103 @@ +/* { dg-require-effective-target vect_int } */ + +#include +#include +#include "tree-vect.h" + +#define N 160 + +typedef struct { + unsigned char a; + unsigned char b; + unsigned char c; + unsigned char d; + unsigned char e; + unsigned char f; + unsigned char g; + unsigned char h; +} s; + +__attribute__ ((noinline)) int +main1 (s *arr, int n) +{ + int i; + s *ptr = arr; + s res[N]; + unsigned char x; + + /* Check peeling for gaps for unknown loop bound. */ + for (i = 0; i < n; i++) + { + res[i].c = ptr->b + ptr->c; + x = ptr->c + ptr->f; + res[i].a = x + ptr->b; + res[i].d = ptr->b + ptr->c; + res[i].b = ptr->c; + res[i].f = ptr->f + ptr->e; + res[i].e = ptr->b + ptr->e; + res[i].h = ptr->c; + res[i].g = ptr->b + ptr->c; + ptr++; + } + + /* check results: */ + for (i = 0; i < n; i++) + { + if (res[i].c != arr[i].b + arr[i].c + || res[i].a != arr[i].c + arr[i].f + arr[i].b + || res[i].d != arr[i].b + arr[i].c + || res[i].b != arr[i].c + || res[i].f != arr[i].f + arr[i].e + || res[i].e != arr[i].b + arr[i].e + || res[i].h != arr[i].c + || res[i].g != arr[i].b + arr[i].c) + abort (); + } + + /* Check also that we don't do more iterations than needed. */ + for (i = n; i < N; i++) + { + if (res[i].c == arr[i].b + arr[i].c + || res[i].a == arr[i].c + arr[i].f + arr[i].b + || res[i].d == arr[i].b + arr[i].c + || res[i].b == arr[i].c + || res[i].f == arr[i].f + arr[i].e + || res[i].e == arr[i].b + arr[i].e + || res[i].h == arr[i].c + || res[i].g == arr[i].b + arr[i].c) + abort (); + } + + return 0; +} + + +int main (void) +{ + int i; + s arr[N]; + + check_vect (); + + for (i = 0; i < N; i++) + { + arr[i].a = 5; + arr[i].b = 6; + arr[i].c = 17; + arr[i].d = 3; + arr[i].e = 16; + arr[i].f = 16; + arr[i].g = 3; + arr[i].h = 56; + if (arr[i].a == 178) + abort(); + } + + main1 (arr, N-2); + + return 0; +} + +/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target vect_strided8 } } } */ +/* { dg-final { cleanup-tree-dump "vect" } } */ + diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c index 8d3b2533dc4..ee059977559 100644 --- a/gcc/tree-vect-data-refs.c +++ b/gcc/tree-vect-data-refs.c @@ -2043,7 +2043,7 @@ vect_analyze_group_access (struct data_reference *dr) loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); bb_vec_info bb_vinfo = STMT_VINFO_BB_VINFO (stmt_info); HOST_WIDE_INT dr_step = TREE_INT_CST_LOW (step); - HOST_WIDE_INT stride; + HOST_WIDE_INT stride, last_accessed_element = 1; bool slp_impossible = false; /* For interleaving, STRIDE is STEP counted in elements, i.e., the size of the @@ -2072,6 +2072,16 @@ vect_analyze_group_access (struct data_reference *dr) fprintf (vect_dump, " step "); print_generic_expr (vect_dump, step, TDF_SLIM); } + + if (loop_vinfo) + { + LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo) = true; + + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "Data access with gaps requires scalar " + "epilogue loop"); + } + return true; } @@ -2137,6 +2147,7 @@ vect_analyze_group_access (struct data_reference *dr) next = GROUP_NEXT_ELEMENT (vinfo_for_stmt (next)); continue; } + prev = next; /* Check that all the accesses have the same STEP. */ @@ -2167,6 +2178,8 @@ vect_analyze_group_access (struct data_reference *dr) gaps += diff - 1; } + last_accessed_element += diff; + /* Store the gap from the previous member of the group. If there is no gap in the access, GROUP_GAP is always 1. */ GROUP_GAP (vinfo_for_stmt (next)) = diff; @@ -2245,6 +2258,15 @@ vect_analyze_group_access (struct data_reference *dr) VEC_safe_push (gimple, heap, BB_VINFO_STRIDED_STORES (bb_vinfo), stmt); } + + /* There is a gap in the end of the group. */ + if (stride - last_accessed_element > 0 && loop_vinfo) + { + LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo) = true; + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "Data access with gaps requires scalar " + "epilogue loop"); + } } return true; diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c index 7619d74b910..89b45745364 100644 --- a/gcc/tree-vect-loop-manip.c +++ b/gcc/tree-vect-loop-manip.c @@ -1551,7 +1551,7 @@ vect_generate_tmps_on_preheader (loop_vec_info loop_vinfo, edge pe; basic_block new_bb; gimple_seq stmts; - tree ni_name; + tree ni_name, ni_minus_gap_name; tree var; tree ratio_name; tree ratio_mult_vf_name; @@ -1568,9 +1568,39 @@ vect_generate_tmps_on_preheader (loop_vec_info loop_vinfo, ni_name = vect_build_loop_niters (loop_vinfo, cond_expr_stmt_list); log_vf = build_int_cst (TREE_TYPE (ni), exact_log2 (vf)); + /* If epilogue loop is required because of data accesses with gaps, we + subtract one iteration from the total number of iterations here for + correct calculation of RATIO. */ + if (LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo)) + { + ni_minus_gap_name = fold_build2 (MINUS_EXPR, TREE_TYPE (ni_name), + ni_name, + build_one_cst (TREE_TYPE (ni_name))); + if (!is_gimple_val (ni_minus_gap_name)) + { + var = create_tmp_var (TREE_TYPE (ni), "ni_gap"); + add_referenced_var (var); + + stmts = NULL; + ni_minus_gap_name = force_gimple_operand (ni_minus_gap_name, &stmts, + true, var); + if (cond_expr_stmt_list) + gimple_seq_add_seq (&cond_expr_stmt_list, stmts); + else + { + pe = loop_preheader_edge (loop); + new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts); + gcc_assert (!new_bb); + } + } + } + else + ni_minus_gap_name = ni_name; + /* Create: ratio = ni >> log2(vf) */ - ratio_name = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ni_name), ni_name, log_vf); + ratio_name = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ni_minus_gap_name), + ni_minus_gap_name, log_vf); if (!is_gimple_val (ratio_name)) { var = create_tmp_var (TREE_TYPE (ni), "bnd"); diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index 98bb113629e..666bd9b0fa7 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -761,6 +761,7 @@ new_loop_vec_info (struct loop *loop) LOOP_VINFO_SLP_INSTANCES (res) = VEC_alloc (slp_instance, heap, 10); LOOP_VINFO_SLP_UNROLLING_FACTOR (res) = 1; LOOP_VINFO_PEELING_HTAB (res) = NULL; + LOOP_VINFO_PEELING_FOR_GAPS (res) = false; return res; } @@ -2333,6 +2334,10 @@ vect_get_known_peeling_cost (loop_vec_info loop_vinfo, int peel_iters_prologue, peel_iters_prologue = niters < peel_iters_prologue ? niters : peel_iters_prologue; *peel_iters_epilogue = (niters - peel_iters_prologue) % vf; + /* If we need to peel for gaps, but no peeling is required, we have to + peel VF iterations. */ + if (LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo) && !*peel_iters_epilogue) + *peel_iters_epilogue = vf; } return (peel_iters_prologue * scalar_single_iter_cost) @@ -4987,7 +4992,8 @@ vect_transform_loop (loop_vec_info loop_vinfo) do_peeling_for_loop_bound = (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo) || (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo) - && LOOP_VINFO_INT_NITERS (loop_vinfo) % vectorization_factor != 0)); + && LOOP_VINFO_INT_NITERS (loop_vinfo) % vectorization_factor != 0) + || LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo)); if (LOOP_REQUIRES_VERSIONING_FOR_ALIGNMENT (loop_vinfo) || LOOP_REQUIRES_VERSIONING_FOR_ALIAS (loop_vinfo)) diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h index a0aed8c849d..3a0a65e9317 100644 --- a/gcc/tree-vectorizer.h +++ b/gcc/tree-vectorizer.h @@ -255,6 +255,11 @@ typedef struct _loop_vec_info { /* Hash table used to choose the best peeling option. */ htab_t peeling_htab; + /* When we have strided data accesses with gaps, we may introduce invalid + memory accesses. We peel the last iteration of the loop to prevent + this. */ + bool peeling_for_gaps; + } *loop_vec_info; /* Access Functions. */ @@ -283,6 +288,7 @@ typedef struct _loop_vec_info { #define LOOP_VINFO_REDUCTIONS(L) (L)->reductions #define LOOP_VINFO_REDUCTION_CHAINS(L) (L)->reduction_chains #define LOOP_VINFO_PEELING_HTAB(L) (L)->peeling_htab +#define LOOP_VINFO_PEELING_FOR_GAPS(L) (L)->peeling_for_gaps #define LOOP_REQUIRES_VERSIONING_FOR_ALIGNMENT(L) \ VEC_length (gimple, (L)->may_misalign_stmts) > 0 -- 2.30.2