introduce fp_no_float_fold flag for frontends which do not query the backends float...

[r24609]

diff --git a/include/libfirm/iropt.h b/include/libfirm/iropt.h
index e008ede..9203ef8 100644 (file)
--- a/include/libfirm/iropt.h
+++ b/include/libfirm/iropt.h
@@ -51,20 +51,24 @@
  * - fp_model_fast:
  *     Fastest mode. Associative and distributive law allowed at the expense
  *     of floating point accuracy and correctness. Explicit rounding is disabled.
+ * - fp_no_float_fold:
+ *     Avoid floating point constant folding. Usefull for frontends which do not
+ *     create arithmetic operations in the backends arithmetic mode.
  */
 typedef enum _fp_model_t {
-       fp_explicit_rounding  =  1,  /**< Explicit rounding at assignments, typecasts, return
+       fp_explicit_rounding  = (1u << 0),  /**< Explicit rounding at assignments, typecasts, return
                                          and function calls. Conv nodes may NOT be removed, even
                                          if they look useless. */
-       fp_strict_algebraic   =  2,  /**< Strict adherence to non-associative and non-distributive
+       fp_strict_algebraic   = (1u << 1),  /**< Strict adherence to non-associative and non-distributive
                                          algebra unless the same result is guaranteed. */
-       fp_contradictions     =  4,  /**< FP contradictions are enabled. Only for backend. */
-       fp_strict_eval_order  =  8,  /**< FP instructions must be strict evaluated in given order. */
-       fp_exceptions         = 16,  /**< FP exceptions are supported. No reordering that changes
+       fp_contradictions     = (1u << 2),  /**< FP contradictions are enabled. Only for backend. */
+       fp_strict_eval_order  = (1u << 3),  /**< FP instructions must be strict evaluated in given order. */
+       fp_exceptions         = (1u << 4),  /**< FP exceptions are supported. No reordering that changes
                                          the exception flow are allowed. Backends must generate
                                          synchronized exception code. */
-       fp_environment_access = 32,  /**< FPU environment can be accessed. Even Constant folding
+       fp_environment_access = (1u << 5),  /**< FPU environment can be accessed. Even Constant folding
                                          cannot be done. */
+       fp_no_float_fold      = (1u << 6),
 
        /** Precise floating point model. Default. */
        fp_model_precise = fp_explicit_rounding|fp_strict_algebraic|fp_contradictions,

diff --git a/ir/ir/iropt.c b/ir/ir/iropt.c
index 265daad..92df9f6 100644 (file)
--- a/ir/ir/iropt.c
+++ b/ir/ir/iropt.c
@@ -6343,7 +6343,8 @@ ir_node *optimize_node(ir_node *n) {
                        unsigned fp_model = get_irg_fp_model(current_ir_graph);
                        int old_fp_mode = tarval_fp_ops_enabled();
 
-                       tarval_enable_fp_ops((fp_model & fp_strict_algebraic) == 0);
+                       tarval_enable_fp_ops(! (fp_model & fp_no_float_fold));
+
                        /* try to evaluate */
                        tv = computed_value(n);
                        if (tv != tarval_bad) {