From: Bill Schmidt Date: Fri, 12 Aug 2016 15:23:34 +0000 (+0000) Subject: rs6000.c (rs6000_builtin_vectorization_cost): Correct costs for vec_construct. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=42b5ebf32cc8da61acd04925d8736c7827549dfa;p=gcc.git rs6000.c (rs6000_builtin_vectorization_cost): Correct costs for vec_construct. 2016-08-12 Bill Schmidt * config/rs6000/rs6000.c (rs6000_builtin_vectorization_cost): Correct costs for vec_construct. From-SVN: r239417 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index e0dab59f4c5..49f0b6d073c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2016-08-12 Bill Schmidt + + * config/rs6000/rs6000.c (rs6000_builtin_vectorization_cost): + Correct costs for vec_construct. + 2016-08-12 Bin Cheng PR tree-optimization/69848 diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c index 756e69df3c5..e58ede1e9f2 100644 --- a/gcc/config/rs6000/rs6000.c +++ b/gcc/config/rs6000/rs6000.c @@ -5266,16 +5266,20 @@ rs6000_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost, return 2; case vec_construct: - elements = TYPE_VECTOR_SUBPARTS (vectype); + /* This is a rough approximation assuming non-constant elements + constructed into a vector via element insertion. FIXME: + vec_construct is not granular enough for uniformly good + decisions. If the initialization is a splat, this is + cheaper than we estimate. Improve this someday. */ elem_type = TREE_TYPE (vectype); /* 32-bit vectors loaded into registers are stored as double - precision, so we need n/2 converts in addition to the usual - n/2 merges to construct a vector of short floats from them. */ + precision, so we need 2 permutes, 2 converts, and 1 merge + to construct a vector of short floats from them. */ if (SCALAR_FLOAT_TYPE_P (elem_type) && TYPE_PRECISION (elem_type) == 32) - return elements + 1; + return 5; else - return elements / 2 + 1; + return max (2, TYPE_VECTOR_SUBPARTS (vectype) - 1); default: gcc_unreachable ();