fix: order of evaluation for some builtins

ecadd, ecmul, addmod, mulmod

in the case that the arguments have side effects, they could be
evaluated out of order

chainsec june 2023 review 5.1

vyper/builtins/functions.py

@@ -814,7 +814,7 @@ def build_IR(self, expr, args, kwargs, context):
                 typ=SArrayT(UINT256_T, 2),
                 location=MEMORY,
             )
-            return b2.resolve(b1.resolve(o))
+            return b1.resolve(b2.resolve(o))
 
 
 class ECMul(BuiltinFunction):
@@ -844,7 +844,7 @@ def build_IR(self, expr, args, kwargs, context):
                 typ=SArrayT(UINT256_T, 2),
                 location=MEMORY,
             )
-            return b2.resolve(b1.resolve(o))
+            return b1.resolve(b2.resolve(o))
 
 
 def _generic_element_getter(op):
@@ -1525,13 +1525,14 @@ def evaluate(self, node):
 
     @process_inputs
     def build_IR(self, expr, args, kwargs, context):
-        c = args[2]
-
-        with c.cache_when_complex("c") as (b1, c):
-            ret = IRnode.from_list(
-                ["seq", ["assert", c], [self._opcode, args[0], args[1], c]], typ=UINT256_T
-            )
-            return b1.resolve(ret)
+        x, y, z = args
+        with x.cache_when_complex("x") as (b1, x):
+            with y.cache_when_complex("y") as (b2, y):
+                with z.cache_when_complex("z") as (b3, z):
+                    ret = IRnode.from_list(
+                        ["seq", ["assert", z], [self._opcode, x, y, z]], typ=UINT256_T
+                    )
+                    return b1.resolve(b2.resolve(b3.resolve(ret)))
 
 
 class AddMod(_AddMulMod):