diff options
Diffstat (limited to 'gcc/tree-ssa-sccvn.c')
| -rw-r--r-- | gcc/tree-ssa-sccvn.c | 55 |
1 files changed, 34 insertions, 21 deletions
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index 2609f668942..07bfdcccb81 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -2715,18 +2715,13 @@ static tree valueize_expr (tree expr); static bool visit_copy (tree lhs, tree rhs) { - /* Follow chains of copies to their destination. */ - while (TREE_CODE (rhs) == SSA_NAME - && SSA_VAL (rhs) != rhs) - rhs = SSA_VAL (rhs); - /* The copy may have a more interesting constant filled expression (we don't, since we know our RHS is just an SSA name). */ - if (TREE_CODE (rhs) == SSA_NAME) - { - VN_INFO (lhs)->has_constants = VN_INFO (rhs)->has_constants; - VN_INFO (lhs)->expr = VN_INFO (rhs)->expr; - } + VN_INFO (lhs)->has_constants = VN_INFO (rhs)->has_constants; + VN_INFO (lhs)->expr = VN_INFO (rhs)->expr; + + /* And finally valueize. */ + rhs = SSA_VAL (rhs); return set_ssa_val_to (lhs, rhs); } @@ -3125,25 +3120,38 @@ expr_has_constants (tree expr) static bool stmt_has_constants (gimple stmt) { + tree tem; + if (gimple_code (stmt) != GIMPLE_ASSIGN) return false; switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt))) { - case GIMPLE_UNARY_RHS: - return is_gimple_min_invariant (gimple_assign_rhs1 (stmt)); + case GIMPLE_TERNARY_RHS: + tem = gimple_assign_rhs3 (stmt); + if (TREE_CODE (tem) == SSA_NAME) + tem = SSA_VAL (tem); + if (is_gimple_min_invariant (tem)) + return true; + /* Fallthru. */ case GIMPLE_BINARY_RHS: - return (is_gimple_min_invariant (gimple_assign_rhs1 (stmt)) - || is_gimple_min_invariant (gimple_assign_rhs2 (stmt))); - case GIMPLE_TERNARY_RHS: - return (is_gimple_min_invariant (gimple_assign_rhs1 (stmt)) - || is_gimple_min_invariant (gimple_assign_rhs2 (stmt)) - || is_gimple_min_invariant (gimple_assign_rhs3 (stmt))); + tem = gimple_assign_rhs2 (stmt); + if (TREE_CODE (tem) == SSA_NAME) + tem = SSA_VAL (tem); + if (is_gimple_min_invariant (tem)) + return true; + /* Fallthru. */ + case GIMPLE_SINGLE_RHS: /* Constants inside reference ops are rarely interesting, but it can take a lot of looking to find them. */ - return is_gimple_min_invariant (gimple_assign_rhs1 (stmt)); + case GIMPLE_UNARY_RHS: + tem = gimple_assign_rhs1 (stmt); + if (TREE_CODE (tem) == SSA_NAME) + tem = SSA_VAL (tem); + return is_gimple_min_invariant (tem); + default: gcc_unreachable (); } @@ -3561,8 +3569,13 @@ visit_use (tree use) We can value number 2 calls to the same function with the same vuse and the same operands which are not subsequent the same, because there is no code in the program that can - compare the 2 values. */ - || gimple_vdef (stmt))) + compare the 2 values... */ + || (gimple_vdef (stmt) + /* ... unless the call returns a pointer which does + not alias with anything else. In which case the + information that the values are distinct are encoded + in the IL. */ + && !(gimple_call_return_flags (stmt) & ERF_NOALIAS)))) changed = visit_reference_op_call (lhs, stmt); else changed = defs_to_varying (stmt); |