diff options
Diffstat (limited to 'gcc/tree-ssa-threadedge.c')
| -rw-r--r-- | gcc/tree-ssa-threadedge.c | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/gcc/tree-ssa-threadedge.c b/gcc/tree-ssa-threadedge.c index 5ca9458..da2fb1f 100644 --- a/gcc/tree-ssa-threadedge.c +++ b/gcc/tree-ssa-threadedge.c @@ -551,11 +551,13 @@ simplify_control_stmt_condition (edge e, || !is_gimple_min_invariant (cached_lhs)) cached_lhs = (*simplify) (dummy_cond, stmt, avail_exprs_stack); - /* If we were just testing that an integral type was != 0, and that - failed, just return the first operand. This gives the FSM code a - chance to optimize the path. */ - if (cached_lhs == NULL - && cond_code == NE_EXPR) + /* If we were testing an integer/pointer against a constant, then + we can use the FSM code to trace the value of the SSA_NAME. If + a value is found, then the condition will collapse to a constant. + + Return the SSA_NAME we want to trace back rather than the full + expression and give the FSM threader a chance to find its value. */ + if (cached_lhs == NULL) { /* Recover the original operands. They may have been simplified using context sensitive equivalences. Those context sensitive @@ -563,9 +565,10 @@ simplify_control_stmt_condition (edge e, tree op0 = gimple_cond_lhs (stmt); tree op1 = gimple_cond_rhs (stmt); - if (INTEGRAL_TYPE_P (TREE_TYPE (op0)) + if ((INTEGRAL_TYPE_P (TREE_TYPE (op0)) + || POINTER_TYPE_P (TREE_TYPE (op0))) && TREE_CODE (op0) == SSA_NAME - && integer_zerop (op1)) + && TREE_CODE (op1) == INTEGER_CST) return op0; } @@ -1046,11 +1049,19 @@ thread_through_normal_block (edge e, if (!flag_expensive_optimizations || optimize_function_for_size_p (cfun) - || TREE_CODE (cond) != SSA_NAME + || !(TREE_CODE (cond) == SSA_NAME + || (TREE_CODE_CLASS (TREE_CODE (cond)) == tcc_comparison + && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME + && TREE_CODE (TREE_OPERAND (cond, 1)) == INTEGER_CST)) || e->dest->loop_father != e->src->loop_father || loop_depth (e->dest->loop_father) == 0) return 0; + /* Extract the SSA_NAME we want to trace backwards if COND is not + already a bare SSA_NAME. */ + if (TREE_CODE (cond) != SSA_NAME) + cond = TREE_OPERAND (cond, 0); + /* When COND cannot be simplified, try to find paths from a control statement back through the PHI nodes which would affect that control statement. */ |