diff options
Diffstat (limited to 'gcc/tree-vect-data-refs.c')
| -rw-r--r-- | gcc/tree-vect-data-refs.c | 84 |
1 files changed, 77 insertions, 7 deletions
diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c index 2408b45..c76c60b 100644 --- a/gcc/tree-vect-data-refs.c +++ b/gcc/tree-vect-data-refs.c @@ -322,6 +322,64 @@ vect_equal_offsets (tree offset1, tree offset2) } +/* Check dependence between DRA and DRB for basic block vectorization. */ + +static bool +vect_drs_dependent_in_basic_block (struct data_reference *dra, + struct data_reference *drb) +{ + HOST_WIDE_INT type_size_a, type_size_b, init_a, init_b; + gimple earlier_stmt; + + /* We only call this function for pairs of loads and stores, but we verify + it here. */ + if (DR_IS_READ (dra) == DR_IS_READ (drb)) + { + if (DR_IS_READ (dra)) + return false; + else + return true; + } + + /* Check that the data-refs have same bases and offsets. If not, we can't + determine if they are dependent. */ + if ((DR_BASE_ADDRESS (dra) != DR_BASE_ADDRESS (drb) + && (TREE_CODE (DR_BASE_ADDRESS (dra)) != ADDR_EXPR + || TREE_CODE (DR_BASE_ADDRESS (drb)) != ADDR_EXPR + || TREE_OPERAND (DR_BASE_ADDRESS (dra), 0) + != TREE_OPERAND (DR_BASE_ADDRESS (drb),0))) + || !vect_equal_offsets (DR_OFFSET (dra), DR_OFFSET (drb))) + return true; + + /* Check the types. */ + type_size_a = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dra)))); + type_size_b = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (drb)))); + + if (type_size_a != type_size_b + || !types_compatible_p (TREE_TYPE (DR_REF (dra)), + TREE_TYPE (DR_REF (drb)))) + return true; + + init_a = TREE_INT_CST_LOW (DR_INIT (dra)); + init_b = TREE_INT_CST_LOW (DR_INIT (drb)); + + /* Two different locations - no dependence. */ + if (init_a != init_b) + return false; + + /* We have a read-write dependence. Check that the load is before the store. + When we vectorize basic blocks, vector load can be only before + corresponding scalar load, and vector store can be only after its + corresponding scalar store. So the order of the acceses is preserved in + case the load is before the store. */ + earlier_stmt = get_earlier_stmt (DR_STMT (dra), DR_STMT (drb)); + if (DR_IS_READ (STMT_VINFO_DATA_REF (vinfo_for_stmt (earlier_stmt)))) + return false; + + return true; +} + + /* Function vect_check_interleaving. Check if DRA and DRB are a part of interleaving. In case they are, insert @@ -495,7 +553,8 @@ vect_mark_for_runtime_alias_test (ddr_p ddr, loop_vec_info loop_vinfo) static bool vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr, - loop_vec_info loop_vinfo, int *max_vf) + loop_vec_info loop_vinfo, int *max_vf, + bool *data_dependence_in_bb) { unsigned int i; struct loop *loop = NULL; @@ -554,10 +613,14 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr, print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); } - /* Mark the statements as unvectorizable. */ - STMT_VINFO_VECTORIZABLE (stmtinfo_a) = false; - STMT_VINFO_VECTORIZABLE (stmtinfo_b) = false; + /* We do not vectorize basic blocks with write-write dependencies. */ + if (!DR_IS_READ (dra) && !DR_IS_READ (drb)) + return true; + /* We deal with read-write dependencies in basic blocks later (by + verifying that all the loads in the basic block are before all the + stores). */ + *data_dependence_in_bb = true; return false; } @@ -577,7 +640,12 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr, print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); } - return true; + /* Do not vectorize basic blcoks with write-write dependences. */ + if (!DR_IS_READ (dra) && !DR_IS_READ (drb)) + return true; + + /* Check if this dependence is allowed in basic block vectorization. */ + return vect_drs_dependent_in_basic_block (dra, drb); } /* Loop-based vectorization and known data dependence. */ @@ -678,7 +746,8 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr, bool vect_analyze_data_ref_dependences (loop_vec_info loop_vinfo, - bb_vec_info bb_vinfo, int *max_vf) + bb_vec_info bb_vinfo, int *max_vf, + bool *data_dependence_in_bb) { unsigned int i; VEC (ddr_p, heap) *ddrs = NULL; @@ -693,7 +762,8 @@ vect_analyze_data_ref_dependences (loop_vec_info loop_vinfo, ddrs = BB_VINFO_DDRS (bb_vinfo); FOR_EACH_VEC_ELT (ddr_p, ddrs, i, ddr) - if (vect_analyze_data_ref_dependence (ddr, loop_vinfo, max_vf)) + if (vect_analyze_data_ref_dependence (ddr, loop_vinfo, max_vf, + data_dependence_in_bb)) return false; return true; |