Fixed division in constant flding.

src/optimize/advanced.py

@@ -173,13 +173,11 @@ def fold_constants(block):
             # Move of `Hi' register to another register
             register[s[0]] = register['$hi']
             known.append((s[0], register[s[0]]))
-        elif s.name in ['mult', 'div'] \
-                and s[0]in register and s[1] in register:
+        elif s.name == 'mult' and s[0]in register and s[1] in register:
             # Multiplication/division with constants
             rs, rt = s
             a, b = register[rs], register[rt]
 
-            if s.name == 'mult':
             if not a or not b:
                 # Multiplication by 0
                 hi = lo = to_hex(0)
@@ -209,13 +207,11 @@ def fold_constants(block):
             block.replace(1, [S('command', 'li', '$hi', hi),
                                 S('command', 'li', '$lo', li)],
                             message=message)
-            elif s.name == 'div':
-                lo, hi = divmod(rs, rt)
 
             register['$lo'], register['$hi'] = lo, hi
             known += [('$lo', lo), ('$hi', hi)]
             changed = True
-        elif s.name in ['addu', 'subu']:
+        elif s.name in ['addu', 'subu', 'div']:
             # Addition/subtraction with constants
             rd, rs, rt = s
             rs_known = rs in register
@@ -239,6 +235,11 @@ def fold_constants(block):
                     message = 'Constant subtraction: %d - %d = %d' \
                               % (rs_val, rt_val, result)
 
+                if s.name == 'div':
+                    result = rs_val / rt_val
+                    message = 'Constant division: %d - %d = %d' \
+                              % (rs_val, rt_val, result)
+
                 block.replace(1, [S('command', 'li', rd, to_hex(result))],
                               message=message)
                 register[rd] = result