From ea60dd34cd352452eeab30aba4b84a204f2caef5 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Thu, 29 Sep 2016 07:16:10 +0000 Subject: [PATCH] tree-vect-stmts.c (vectorizable_load): Avoid emitting vector constructors with vector elements. 2016-09-29 Richard Biener * tree-vect-stmts.c (vectorizable_load): Avoid emitting vector constructors with vector elements. From-SVN: r240611 --- gcc/ChangeLog | 5 +++++ gcc/tree-vect-stmts.c | 41 ++++++++++++++++++++++++++++++++++++----- 2 files changed, 41 insertions(+), 5 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index eac95464ee0..56f7255a2b0 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2016-09-29 Richard Biener + + * tree-vect-stmts.c (vectorizable_load): Avoid emitting vector + constructors with vector elements. + 2016-09-29 Richard Biener PR tree-optimization/77768 diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c index 47770adcdc0..d698785a547 100644 --- a/gcc/tree-vect-stmts.c +++ b/gcc/tree-vect-stmts.c @@ -6862,17 +6862,40 @@ vectorizable_load (gimple *stmt, gimple_stmt_iterator *gsi, gimple **vec_stmt, int nloads = nunits; int lnel = 1; tree ltype = TREE_TYPE (vectype); + tree lvectype = vectype; auto_vec dr_chain; if (memory_access_type == VMAT_STRIDED_SLP) { - nloads = nunits / group_size; if (group_size < nunits) { - lnel = group_size; - ltype = build_vector_type (TREE_TYPE (vectype), group_size); + /* Avoid emitting a constructor of vector elements by performing + the loads using an integer type of the same size, + constructing a vector of those and then re-interpreting it + as the original vector type. This works around the fact + that the vec_init optab was only designed for scalar + element modes and thus expansion goes through memory. + This avoids a huge runtime penalty due to the general + inability to perform store forwarding from smaller stores + to a larger load. */ + unsigned lsize + = group_size * TYPE_PRECISION (TREE_TYPE (vectype)); + enum machine_mode elmode = mode_for_size (lsize, MODE_INT, 0); + enum machine_mode vmode = mode_for_vector (elmode, + nunits / group_size); + /* If we can't construct such a vector fall back to + element loads of the original vector type. */ + if (VECTOR_MODE_P (vmode) + && optab_handler (vec_init_optab, vmode) != CODE_FOR_nothing) + { + nloads = nunits / group_size; + lnel = group_size; + ltype = build_nonstandard_integer_type (lsize, 1); + lvectype = build_vector_type (ltype, nloads); + } } else { + nloads = 1; lnel = nunits; ltype = vectype; } @@ -6925,9 +6948,17 @@ vectorizable_load (gimple *stmt, gimple_stmt_iterator *gsi, gimple **vec_stmt, } if (nloads > 1) { - tree vec_inv = build_constructor (vectype, v); - new_temp = vect_init_vector (stmt, vec_inv, vectype, gsi); + tree vec_inv = build_constructor (lvectype, v); + new_temp = vect_init_vector (stmt, vec_inv, lvectype, gsi); new_stmt = SSA_NAME_DEF_STMT (new_temp); + if (lvectype != vectype) + { + new_stmt = gimple_build_assign (make_ssa_name (vectype), + VIEW_CONVERT_EXPR, + build1 (VIEW_CONVERT_EXPR, + vectype, new_temp)); + vect_finish_stmt_generation (stmt, new_stmt, gsi); + } } if (slp) -- 2.30.2