On Thu, Aug 4, 2011 at 9:47 AM, Ira Rosen <ira.ro...@linaro.org> wrote: > On 19 July 2011 09:44, Ira Rosen <ira.ro...@linaro.org> wrote: >> Hi, >> >> This patch tries to reduce over-promotion of vector operations that >> could be done with narrower elements, e.g., for >> >> char a; >> int b, c; >> short d; >> >> b = (int) a; >> c = b << 2; >> d = (short) c; >> >> we currently produce six vec_unpack_lo/hi_expr statements for >> char->int conversion and then two vec_pack_trunc_expr for short->int. >> While the shift can be performed on short, using only two >> vec_unpack_lo/hi_expr operations for char->short conversion in this >> example. >> >> With this patch we detect such over-promoted sequences that start with >> a type promotion operation and end with a type demotion operation. The >> statements in between are checked if they can be performed using >> smaller type (this patch only adds a support for shifts and bit >> operations with a constant). If a sequence is detected we create a >> sequence of scalar pattern statements to be vectorized instead the >> original one. Since there may be two pattern statements created for >> the same original statement - the operation itself (on an intermediate >> type) and a type promotion (from a smaller type to the intermediate >> type) for the non-constant operand - this patch adds a new field to >> struct _stmt_vec_info to keep that pattern def statement. >> >> Bootstrapped and tested on powerpc64-suse-linux. >> Comments are welcome. > > I committed the attached version which incorporates Richard's comments > from here http://gcc.gnu.org/ml/gcc-patches/2011-08/msg00144.html. > > Thanks, > Ira > >> >> Thanks, >> Ira >> >> ChangeLog: >> >> * tree-vectorizer.h (struct _stmt_vec_info): Add new field for >> pattern def statement, and its access macro. >> (NUM_PATTERNS): Set to 5. >> * tree-vect-loop.c (vect_determine_vectorization_factor): Handle >> pattern def statement. >> (vect_transform_loop): Likewise. >> * tree-vect-patterns.c (vect_vect_recog_func_ptrs): Add new >> function vect_recog_over_widening_pattern (). >> (vect_operation_fits_smaller_type): New function. >> (vect_recog_over_widening_pattern, vect_mark_pattern_stmts): >> Likewise. >> (vect_pattern_recog_1): Move the code that marks pattern >> statements to vect_mark_pattern_stmts (), and call it. Update >> documentation. >> * tree-vect-stmts.c (vect_supportable_shift): New function. >> (vect_analyze_stmt): Handle pattern def statement. >> (new_stmt_vec_info): Initialize pattern def statement.
This caused: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53693 -- H.J.
