Hi, With the patch enabling the vectorization of early-breaks, we'd like to allow bitfield lowering in such loops, which requires the relaxation of allowing multiple exits when doing so. In order to avoid a similar issue to PR107275, the code that rejects loops with certain types of gimple_stmts was hoisted from 'if_convertible_loop_p_1' to 'get_loop_body_in_if_conv_order', to avoid trying to lower bitfields in loops we are not going to vectorize anyway. This also ensures 'ifcvt_local_dec' doesn't accidentally remove statements it shouldn't as it will never come across them. I made sure to add a comment to make clear that there is a direct connection between the two and if we were to enable vectorization of any other gimple statement we should make sure both handle it. NOTE: This patch accepted before but never committed because it is a no-op without the early break patch. This is a respun version of Andre's patch and rebased to changes in ifcvt and updated to handle multiple exits. Bootstrappend and regression tested on aarch64-none-linux-gnu and x86_64-pc-linux-gnu and no issues. gcc/ChangeLog: * tree-if-conv.cc (if_convertible_loop_p_1): Move check from here ... (get_loop_body_if_conv_order): ... to here. (if_convertible_loop_p): Remove single_exit check. (tree_if_conversion): Move single_exit check to if-conversion part and support multiple exits. gcc/testsuite/ChangeLog: * gcc.dg/vect/vect-bitfield-read-1-not.c: New test. * gcc.dg/vect/vect-bitfield-read-2-not.c: New test. * gcc.dg/vect/vect-bitfield-read-8.c: New test. * gcc.dg/vect/vect-bitfield-read-9.c: New test. Co-Authored-By: Andre Vieira --- inline copy of patch -- diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-1-not.c b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-1-not.c new file mode 100644 index 0000000000000000000000000000000000000000..0d91067ebb27b1db2b2352975c43bce8b4171e3f --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-1-not.c @@ -0,0 +1,60 @@ +/* { dg-require-effective-target vect_shift } */ +/* { dg-require-effective-target vect_long_long } */ +/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */ + +#include +#include "tree-vect.h" + +extern void abort(void); + +struct s { + char a : 4; +}; + +#define N 32 +#define ELT0 {0} +#define ELT1 {1} +#define ELT2 {2} +#define ELT3 {3} +#define RES 56 +struct s A[N] + = { ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3}; + +int __attribute__ ((noipa)) +f(struct s *ptr, unsigned n) { + int res = 0; + for (int i = 0; i < n; ++i) + { + switch (ptr[i].a) + { + case 0: + res += ptr[i].a + 1; + break; + case 1: + case 2: + case 3: + res += ptr[i].a; + break; + default: + return 0; + } + } + return res; +} + +int main (void) +{ + check_vect (); + + if (f(&A[0], N) != RES) + abort (); + + return 0; +} + +/* { dg-final { scan-tree-dump-not "Bitfield OK to lower." "ifcvt" } } */ + + diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-2-not.c b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-2-not.c new file mode 100644 index 0000000000000000000000000000000000000000..4ac7b3fc0dfd1c9d0b5e94a2ba6a745545577ec1 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-2-not.c @@ -0,0 +1,49 @@ +/* { dg-require-effective-target vect_shift } */ +/* { dg-require-effective-target vect_long_long } */ +/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */ + +#include +#include "tree-vect.h" + +extern void abort(void); + +struct s { + char a : 4; +}; + +#define N 32 +#define ELT0 {0} +#define ELT1 {1} +#define ELT2 {2} +#define ELT3 {3} +#define RES 48 +struct s A[N] + = { ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3}; + +int __attribute__ ((noipa)) +f(struct s *ptr, unsigned n) { + int res = 0; + for (int i = 0; i < n; ++i) + { + asm volatile ("" ::: "memory"); + res += ptr[i].a; + } + return res; +} + +int main (void) +{ + check_vect (); + + if (f(&A[0], N) != RES) + abort (); + + return 0; +} + +/* { dg-final { scan-tree-dump-not "Bitfield OK to lower." "ifcvt" } } */ + + diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-8.c b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-8.c new file mode 100644 index 0000000000000000000000000000000000000000..52cfd33d937ae90f3fe9556716c90e098b768ac8 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-8.c @@ -0,0 +1,49 @@ +/* { dg-require-effective-target vect_int } */ +/* { dg-require-effective-target vect_shift } */ +/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */ + +#include +#include "tree-vect.h" + +extern void abort(void); + +struct s { int i : 31; }; + +#define ELT0 {0} +#define ELT1 {1} +#define ELT2 {2} +#define ELT3 {3} +#define ELT4 {4} +#define N 32 +#define RES 25 +struct s A[N] + = { ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT4, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3}; + +int __attribute__ ((noipa)) +f(struct s *ptr, unsigned n) { + int res = 0; + for (int i = 0; i < n; ++i) + { + if (ptr[i].i == 4) + return res; + res += ptr[i].i; + } + + return res; +} + +int main (void) +{ + check_vect (); + + if (f(&A[0], N) != RES) + abort (); + + return 0; +} + +/* { dg-final { scan-tree-dump "Bitfield OK to lower." "ifcvt" } } */ + diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-9.c b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-9.c new file mode 100644 index 0000000000000000000000000000000000000000..ab814698131a5905def181eeed85d8a3c62b924b --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-9.c @@ -0,0 +1,51 @@ +/* { dg-require-effective-target vect_shift } */ +/* { dg-require-effective-target vect_long_long } */ +/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */ + +#include +#include "tree-vect.h" + +extern void abort(void); + +struct s { + unsigned i : 31; + char a : 4; +}; + +#define N 32 +#define ELT0 {0x7FFFFFFFUL, 0} +#define ELT1 {0x7FFFFFFFUL, 1} +#define ELT2 {0x7FFFFFFFUL, 2} +#define ELT3 {0x7FFFFFFFUL, 3} +#define ELT4 {0x7FFFFFFFUL, 4} +#define RES 9 +struct s A[N] + = { ELT0, ELT4, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3, + ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3}; + +int __attribute__ ((noipa)) +f(struct s *ptr, unsigned n) { + int res = 0; + for (int i = 0; i < n; ++i) + { + if (ptr[i].a) + return 9; + res += ptr[i].a; + } + return res; +} + +int main (void) +{ + check_vect (); + + if (f(&A[0], N) != RES) + abort (); + + return 0; +} + +/* { dg-final { scan-tree-dump "Bitfield OK to lower." "ifcvt" } } */ + diff --git a/gcc/tree-if-conv.cc b/gcc/tree-if-conv.cc index e342532a343a3c066142adeec5fdfaf736a653e5..cdb0fe4c29dfa531e3277925022d127b13ffcc16 100644 --- a/gcc/tree-if-conv.cc +++ b/gcc/tree-if-conv.cc @@ -586,7 +586,7 @@ add_to_dst_predicate_list (class loop *loop, edge e, /* Return true if one of the successor edges of BB exits LOOP. */ static bool -bb_with_exit_edge_p (class loop *loop, basic_block bb) +bb_with_exit_edge_p (const class loop *loop, basic_block bb) { edge e; edge_iterator ei; @@ -1268,6 +1268,44 @@ get_loop_body_in_if_conv_order (const class loop *loop) } free (blocks_in_bfs_order); BITMAP_FREE (visited); + + /* Go through loop and reject if-conversion or lowering of bitfields if we + encounter statements we do not believe the vectorizer will be able to + handle. If adding a new type of statement here, make sure + 'ifcvt_local_dce' is also able to handle it propertly. */ + for (index = 0; index < loop->num_nodes; index++) + { + basic_block bb = blocks[index]; + gimple_stmt_iterator gsi; + + bool may_have_nonlocal_labels + = bb_with_exit_edge_p (loop, bb) || bb == loop->latch; + for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) + switch (gimple_code (gsi_stmt (gsi))) + { + case GIMPLE_LABEL: + if (!may_have_nonlocal_labels) + { + tree label + = gimple_label_label (as_a (gsi_stmt (gsi))); + if (DECL_NONLOCAL (label) || FORCED_LABEL (label)) + { + free (blocks); + return NULL; + } + } + /* Fallthru. */ + case GIMPLE_ASSIGN: + case GIMPLE_CALL: + case GIMPLE_DEBUG: + case GIMPLE_COND: + gimple_set_uid (gsi_stmt (gsi), 0); + break; + default: + free (blocks); + return NULL; + } + } return blocks; } @@ -1438,36 +1476,6 @@ if_convertible_loop_p_1 (class loop *loop, vec *refs) exit_bb = bb; } - for (i = 0; i < loop->num_nodes; i++) - { - basic_block bb = ifc_bbs[i]; - gimple_stmt_iterator gsi; - - bool may_have_nonlocal_labels - = bb_with_exit_edge_p (loop, bb) || bb == loop->latch; - for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) - switch (gimple_code (gsi_stmt (gsi))) - { - case GIMPLE_LABEL: - if (!may_have_nonlocal_labels) - { - tree label - = gimple_label_label (as_a (gsi_stmt (gsi))); - if (DECL_NONLOCAL (label) || FORCED_LABEL (label)) - return false; - } - /* Fallthru. */ - case GIMPLE_ASSIGN: - case GIMPLE_CALL: - case GIMPLE_DEBUG: - case GIMPLE_COND: - gimple_set_uid (gsi_stmt (gsi), 0); - break; - default: - return false; - } - } - data_reference_p dr; innermost_DR_map @@ -1579,14 +1587,6 @@ if_convertible_loop_p (class loop *loop, vec *refs) return false; } - /* More than one loop exit is too much to handle. */ - if (!single_exit (loop)) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "multiple exits\n"); - return false; - } - /* If one of the loop header's edge is an exit edge then do not apply if-conversion. */ FOR_EACH_EDGE (e, ei, loop->header->succs) @@ -3566,9 +3566,6 @@ tree_if_conversion (class loop *loop, vec *preds) aggressive_if_conv = true; } - if (!single_exit (loop)) - goto cleanup; - /* If there are more than two BBs in the loop then there is at least one if to convert. */ if (loop->num_nodes > 2 @@ -3588,15 +3585,25 @@ tree_if_conversion (class loop *loop, vec *preds) if (loop->num_nodes > 2) { - need_to_ifcvt = true; + /* More than one loop exit is too much to handle. */ + if (!single_exit (loop)) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Can not ifcvt due to multiple exits\n"); + } + else + { + need_to_ifcvt = true; - if (!if_convertible_loop_p (loop, &refs) || !dbg_cnt (if_conversion_tree)) - goto cleanup; + if (!if_convertible_loop_p (loop, &refs) + || !dbg_cnt (if_conversion_tree)) + goto cleanup; - if ((need_to_predicate || any_complicated_phi) - && ((!flag_tree_loop_vectorize && !loop->force_vectorize) - || loop->dont_vectorize)) - goto cleanup; + if ((need_to_predicate || any_complicated_phi) + && ((!flag_tree_loop_vectorize && !loop->force_vectorize) + || loop->dont_vectorize)) + goto cleanup; + } } if ((flag_tree_loop_vectorize || loop->force_vectorize) @@ -3687,7 +3694,8 @@ tree_if_conversion (class loop *loop, vec *preds) PHIs, those are to be kept in sync with the non-if-converted copy. ??? We'll still keep dead stores though. */ exit_bbs = BITMAP_ALLOC (NULL); - bitmap_set_bit (exit_bbs, single_exit (loop)->dest->index); + for (edge exit : get_loop_exit_edges (loop)) + bitmap_set_bit (exit_bbs, exit->dest->index); bitmap_set_bit (exit_bbs, loop->latch->index); std::pair *name_pair; --