diff options
Diffstat (limited to 'gcc/tree-ssa-dom.c')
| -rw-r--r-- | gcc/tree-ssa-dom.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c index e8b1551..57b814c 100644 --- a/gcc/tree-ssa-dom.c +++ b/gcc/tree-ssa-dom.c @@ -1135,6 +1135,33 @@ record_equivalences_from_incoming_edge (basic_block bb) if (lhs) record_equality (lhs, rhs); + /* If LHS is an SSA_NAME and RHS is a constant and LHS was set + via a widening type conversion, then we may be able to record + additional equivalences. */ + if (lhs + && TREE_CODE (lhs) == SSA_NAME + && is_gimple_constant (rhs)) + { + gimple defstmt = SSA_NAME_DEF_STMT (lhs); + + if (defstmt + && is_gimple_assign (defstmt) + && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (defstmt))) + { + tree old_rhs = gimple_assign_rhs1 (defstmt); + tree newval = fold_convert (TREE_TYPE (old_rhs), rhs); + + /* If this was a widening conversion and if RHS is converted + to the type of OLD_RHS and has the same value, then we + can record an equivalence between OLD_RHS and the + converted representation of RHS. */ + if ((TYPE_PRECISION (TREE_TYPE (lhs)) + > TYPE_PRECISION (TREE_TYPE (old_rhs))) + && operand_equal_p (rhs, newval, 0)) + record_equality (old_rhs, newval); + } + } + for (i = 0; edge_info->cond_equivalences.iterate (i, &eq); ++i) record_cond (eq); } |