Record the vector mask precision in stmt_vec_info

Programming / Compilers / GCC - rsandifo [138bc75d-0d04-0410-961f-82ee72b054a4] - 29 November 2019 14:47 EST

search_type_for_mask uses a worklist to search a chain of boolean operations for a natural vector mask type. This patch instead does that in vect_determine_stmt_precisions, where we also look for overpromoted integer operations. We then only need to compute the precision once and can cache it in the stmt_vec_info.

The new function vect_determine_mask_precision is supposed to handle exactly the same cases as search_type_for_mask_1, and in the same way. There's a lot we could improve here, but that's not stage 3 material.

I wondered about sharing mask_precision with other fields like operation_precision, but in the end that seemed too dangerous. We have patterns to convert between boolean and non-boolean operations and it would be very easy to get mixed up about which case the fields are describing.

2019-11-29 Richard Sandiford

- tree-vectorizer.h (stmt_vec_info::mask_precision): New field. (vect_use_mask_type_p): New function.
- tree-vect-patterns.c (vect_init_pattern_stmt): Copy the mask precision to the pattern statement. (append_pattern_def_seq): Add a scalar_type_for_mask parameter and use it to initialize the new stmt's mask precision. (search_type_for_mask_1): Delete. (search_type_for_mask): Replace with... (integer_type_for_mask): ...this new function. Use the information cached in the stmt_vec_info. (vect_recog_bool_pattern): Update accordingly. (build_mask_conversion): Pass the scalar type associated with the mask type to append_pattern_def_seq. (vect_recog_mask_conversion_pattern): Likewise. Call integer_type_for_mask instead of search_type_for_mask. (vect_convert_mask_for_vectype): Call integer_type_for_mask instead of search_type_for_mask. (possible_vector_mask_operation_p): New function. (vect_determine_mask_precision): Likewise. (vect_determine_stmt_precisions): Call it.

1a7144eb381 Record the vector mask precision in stmt_vec_info
gcc/ChangeLog | 23 ++++
gcc/tree-vect-patterns.c | 283 +++++++++++++++++++++++++++++------------------
gcc/tree-vectorizer.h | 26 +++++
3 files changed, 226 insertions(+), 106 deletions(-)


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