https://gcc.gnu.org/g:363b29a9cfbb470d6987fb395035c56bae30c64b
commit r16-2193-g363b29a9cfbb470d6987fb395035c56bae30c64b
Author: Richard Biener <rguent...@suse.de>
Date: Thu Jul 10 13:30:30 2025 +0200
properly compute fp/mode for scalar ops for vectorizer costing
The x86 add_stmt_hook relies on the passed vectype to determine
the mode and whether it is FP for a scalar operation. This is
unreliable now for stmts involving patterns and in the future when
there is no vector type passed for scalar operations.
To be least disruptive I've kept using the vector type if it is passed.
* config/i386/i386.cc (ix86_vector_costs::add_stmt_cost): Use
the LHS of a scalar stmt to determine mode and whether it is FP.
Diff:
---
gcc/config/i386/i386.cc | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index ad7360ec71a4..313522b88e3c 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -25798,6 +25798,14 @@ ix86_vector_costs::add_stmt_cost (int count,
vect_cost_for_stmt kind,
if (scalar_p)
mode = TYPE_MODE (TREE_TYPE (vectype));
}
+ /* When we are costing a scalar stmt use the scalar stmt to get at the
+ type of the operation. */
+ else if (scalar_p && stmt_info)
+ if (tree lhs = gimple_get_lhs (stmt_info->stmt))
+ {
+ fp = FLOAT_TYPE_P (TREE_TYPE (lhs));
+ mode = TYPE_MODE (TREE_TYPE (lhs));
+ }
if ((kind == vector_stmt || kind == scalar_stmt)
&& stmt_info
