2005-07-21 Atsushi Enomoto <atsushi@ximian.com>

[mono.git] / mono / mini / cfold.c

diff --git a/mono/mini/cfold.c b/mono/mini/cfold.c
index 340e5aad85214b36bd60738b6ef08e229baf70dd..c9daabdb7f6c5d4c781fafb13ba90adec44ec3c3 100644 (file)
--- a/mono/mini/cfold.c
+++ b/mono/mini/cfold.c
@@ -51,6 +51,12 @@ mono_is_power_of_two (guint32 val)
                                inst->inst_i1 = tmp;    \
                        } \
                } \
+               if (inst->inst_i1->opcode == OP_ICONST && inst->opcode == CEE_ADD) {    \
+                       if (inst->inst_i1->inst_c0 == 0) { \
+                               *inst = *(inst->inst_i0); \
+                               return; \
+                       } \
+               } \
                if (inst->inst_i1->opcode == OP_ICONST && inst->opcode == CEE_MUL) {    \
                        int power2;     \
                        if (inst->inst_i1->inst_c0 == 1) {      \
@@ -67,6 +73,11 @@ mono_is_power_of_two (guint32 val)
                } \
                 return;
 
+#ifndef G_MININT32
+#define MYGINT32_MAX 2147483647
+#define G_MININT32 (-MYGINT32_MAX -1)
+#endif
+
 /* 
  * We can't let this cause a division by zero exception since the division 
  * might not be executed during runtime.
@@ -243,3 +254,67 @@ mono_constant_fold (MonoCompile *cfg)
        }
 }
 
+/*
+ * If the arguments to the cond branch are constants, eval and
+ * return BRANCH_NOT_TAKEN for not taken, BRANCH_TAKEN for taken,
+ * BRANCH_UNDEF otherwise.
+ * If this code is changed to handle also non-const values, make sure
+ * side effects are handled in optimize_branches() in mini.c, by
+ * inserting pop instructions.
+ */
+int
+mono_eval_cond_branch (MonoInst *ins)
+{
+       MonoInst *left, *right;
+       /* FIXME: handle also 64 bit ints */
+       left = ins->inst_left->inst_left;
+       if (left->opcode != OP_ICONST && left->opcode != OP_PCONST)
+               return BRANCH_UNDEF;
+       right = ins->inst_left->inst_right;
+       if (right->opcode != OP_ICONST && right->opcode != OP_PCONST)
+               return BRANCH_UNDEF;
+       switch (ins->opcode) {
+       case CEE_BEQ:
+               if (left->inst_c0 == right->inst_c0)
+                       return BRANCH_TAKEN;
+               return BRANCH_NOT_TAKEN;
+       case CEE_BGE:
+               if (left->inst_c0 >= right->inst_c0)
+                       return BRANCH_TAKEN;
+               return BRANCH_NOT_TAKEN;
+       case CEE_BGT:
+               if (left->inst_c0 > right->inst_c0)
+                       return BRANCH_TAKEN;
+               return BRANCH_NOT_TAKEN;
+       case CEE_BLE:
+               if (left->inst_c0 <= right->inst_c0)
+                       return BRANCH_TAKEN;
+               return BRANCH_NOT_TAKEN;
+       case CEE_BLT:
+               if (left->inst_c0 < right->inst_c0)
+                       return BRANCH_TAKEN;
+               return BRANCH_NOT_TAKEN;
+       case CEE_BNE_UN:
+               if ((gsize)left->inst_c0 != (gsize)right->inst_c0)
+                       return BRANCH_TAKEN;
+               return BRANCH_NOT_TAKEN;
+       case CEE_BGE_UN:
+               if ((gsize)left->inst_c0 >= (gsize)right->inst_c0)
+                       return BRANCH_TAKEN;
+               return BRANCH_NOT_TAKEN;
+       case CEE_BGT_UN:
+               if ((gsize)left->inst_c0 > (gsize)right->inst_c0)
+                       return BRANCH_TAKEN;
+               return BRANCH_NOT_TAKEN;
+       case CEE_BLE_UN:
+               if ((gsize)left->inst_c0 <= (gsize)right->inst_c0)
+                       return BRANCH_TAKEN;
+               return BRANCH_NOT_TAKEN;
+       case CEE_BLT_UN:
+               if ((gsize)left->inst_c0 < (gsize)right->inst_c0)
+                       return BRANCH_TAKEN;
+               return BRANCH_NOT_TAKEN;
+       }
+       return BRANCH_UNDEF;
+}
+