gcc.target/aarch64/sve/clastb_[57].c started failing after the increase
in the cost of vec_to_scalar (r278452). The problem is that we were
double-counting the cost of the CLASTB: once in vect_model_reduction_cost
as a vec_to_scalar and once in vectorizable_condition as a plain
vector_stmt.
Based on the TODO above vect_model_reduction_cost, I think the
preferred long-term direction is for vectorizable_* to cost these
things itself, so that's what the patch does (for this one case only).
Tested on aarch64-linux-gnu and x86_64-linux-gnu. OK to install?
Richard
2019-11-21 Richard Sandiford <richard.sandif...@arm.com>
gcc/
* tree-vect-stmts.c (vect_model_simple_cost): Take an optional
vect_cost_for_stmt.
(vectorizable_condition): Calculate the cost of EXTRACT_LAST_REDUCTION
here rather than...
* tree-vect-loop.c (vect_model_reduction_cost): ...here.
Index: gcc/tree-vect-stmts.c
===================================================================
--- gcc/tree-vect-stmts.c 2019-11-16 10:29:21.211212189 +0000
+++ gcc/tree-vect-stmts.c 2019-11-21 12:02:44.058240392 +0000
@@ -860,7 +860,8 @@ vect_model_simple_cost (stmt_vec_info st
enum vect_def_type *dt,
int ndts,
slp_tree node,
- stmt_vector_for_cost *cost_vec)
+ stmt_vector_for_cost *cost_vec,
+ vect_cost_for_stmt kind = vector_stmt)
{
int inside_cost = 0, prologue_cost = 0;
@@ -907,7 +908,7 @@ vect_model_simple_cost (stmt_vec_info st
}
/* Pass the inside-of-loop statements to the target-specific cost model. */
- inside_cost += record_stmt_cost (cost_vec, ncopies, vector_stmt,
+ inside_cost += record_stmt_cost (cost_vec, ncopies, kind,
stmt_info, 0, vect_body);
if (dump_enabled_p ())
@@ -10081,15 +10082,18 @@ vectorizable_condition (stmt_vec_info st
return false;
}
}
- if (expand_vec_cond_expr_p (vectype, comp_vectype,
- cond_code))
- {
- STMT_VINFO_TYPE (stmt_info) = condition_vec_info_type;
- vect_model_simple_cost (stmt_info, ncopies, dts, ndts, slp_node,
- cost_vec);
- return true;
- }
- return false;
+
+ vect_cost_for_stmt kind = vector_stmt;
+ if (reduction_type == EXTRACT_LAST_REDUCTION)
+ /* Count one reduction-like operation per vector. */
+ kind = vec_to_scalar;
+ else if (!expand_vec_cond_expr_p (vectype, comp_vectype, cond_code))
+ return false;
+
+ STMT_VINFO_TYPE (stmt_info) = condition_vec_info_type;
+ vect_model_simple_cost (stmt_info, ncopies, dts, ndts, slp_node,
+ cost_vec, kind);
+ return true;
}
/* Transform. */
Index: gcc/tree-vect-loop.c
===================================================================
--- gcc/tree-vect-loop.c 2019-11-19 16:25:24.882645490 +0000
+++ gcc/tree-vect-loop.c 2019-11-21 12:02:44.050240447 +0000
@@ -3924,8 +3924,11 @@ vect_model_reduction_cost (stmt_vec_info
code = gimple_assign_rhs_code (orig_stmt_info->stmt);
- if (reduction_type == EXTRACT_LAST_REDUCTION
- || reduction_type == FOLD_LEFT_REDUCTION)
+ if (reduction_type == EXTRACT_LAST_REDUCTION)
+ /* No extra instructions are needed in the prologue. The loop body
+ operations are costed in vectorizable_condition. */
+ inside_cost = 0;
+ else if (reduction_type == FOLD_LEFT_REDUCTION)
{
/* No extra instructions needed in the prologue. */
prologue_cost = 0;
