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Diffstat (limited to 'gcc/tree-ssa-ccp.c')
| -rw-r--r-- | gcc/tree-ssa-ccp.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c index eeae4bfcd35..996296b4e36 100644 --- a/gcc/tree-ssa-ccp.c +++ b/gcc/tree-ssa-ccp.c @@ -646,6 +646,7 @@ static ccp_lattice_t likely_value (gimple stmt) { bool has_constant_operand, has_undefined_operand, all_undefined_operands; + bool has_nsa_operand; tree use; ssa_op_iter iter; unsigned i; @@ -668,6 +669,7 @@ likely_value (gimple stmt) has_constant_operand = false; has_undefined_operand = false; all_undefined_operands = true; + has_nsa_operand = false; FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) { ccp_prop_value_t *val = get_value (use); @@ -679,6 +681,10 @@ likely_value (gimple stmt) if (val->lattice_val == CONSTANT) has_constant_operand = true; + + if (SSA_NAME_IS_DEFAULT_DEF (use) + || !prop_simulate_again_p (SSA_NAME_DEF_STMT (use))) + has_nsa_operand = true; } /* There may be constants in regular rhs operands. For calls we @@ -751,8 +757,10 @@ likely_value (gimple stmt) /* We do not consider virtual operands here -- load from read-only memory may have only VARYING virtual operands, but still be - constant. */ + constant. Also we can combine the stmt with definitions from + operands whose definitions are not simulated again. */ if (has_constant_operand + || has_nsa_operand || gimple_references_memory_p (stmt)) return CONSTANT; |