Do not materialise the "strict"-part of strictConv(int) unless the source mode has...

[r20955]

diff --git a/ir/be/ia32/ia32_transform.c b/ir/be/ia32/ia32_transform.c
index 44149e4..c9dc1de 100644 (file)
--- a/ir/be/ia32/ia32_transform.c
+++ b/ir/be/ia32/ia32_transform.c
@@ -3483,9 +3483,21 @@ static ir_node *gen_Conv(ir_node *node) {
                        } else {
                                res = gen_x87_gp_to_fp(node, src_mode);
                                if(get_Conv_strict(node)) {
-                                       res = gen_x87_strict_conv(tgt_mode, res);
-                                       SET_IA32_ORIG_NODE(get_Proj_pred(res),
-                                                          ia32_get_old_node_name(env_cg, node));
+                                       /* The strict-Conv is only necessary, if the int mode has more bits
+                                        * than the float mantissa */
+                                       size_t int_mantissa = get_mode_size_bits(src_mode) - (mode_is_signed(src_mode) ? 1 : 0);
+                                       size_t float_mantissa;
+                                       /* FIXME There is no way to get the mantissa size of a mode */
+                                       switch (get_mode_size_bits(tgt_mode)) {
+                                               case 32: float_mantissa = 23 + 1; break; // + 1 for implicit 1
+                                               case 64: float_mantissa = 52 + 1; break;
+                                               case 80: float_mantissa = 64 + 1; break;
+                                               default: float_mantissa = 0;      break;
+                                       }
+                                       if (float_mantissa < int_mantissa) {
+                                               res = gen_x87_strict_conv(tgt_mode, res);
+                                               SET_IA32_ORIG_NODE(get_Proj_pred(res), ia32_get_old_node_name(env_cg, node));
+                                       }
                                }
                                return res;
                        }