UOp mod reduction (#5697)

test/unit/test_symbolic.py

@@ -153,7 +153,7 @@ class TestSymbolic(unittest.TestCase):
 
   def test_mod_to_sub(self):
     # This is mod reduction
-    self.helper_test_variable((1+Variable("a",1,2))%2, 0, 1, (Variable("a",1,2)-1).render())
+    self.helper_test_variable((1+Variable("a",1,2))%2, 0, 1, "(-1+a)")
 
   def test_sum_div_const(self):
     self.helper_test_variable(Node.sum([Variable("a", 0, 7)*4, NumNode(3)]) // 4, 0, 7, "a")

test/unit/test_uop_symbolic.py

@@ -209,10 +209,9 @@ class TestSymbolic(unittest.TestCase):
     # NOTE: even though the mod max is 50, it can't know this without knowing about the mul
     self.helper_test_variable(Node.sum([Variable("a", 0, 7)*100, Variable("b", 0, 3)*50]) % 100, 0, 99, "((b*50)%100)")
 
-  @unittest.expectedFailure
   def test_mod_to_sub(self):
     # This is mod reduction
-    self.helper_test_variable((1+Variable("a",1,2))%2, 0, 1, (Variable("a",1,2)-1).render())
+    self.helper_test_variable((1+Variable("a",1,2))%2, 0, 1, {"(-1+a)", "(a+(-1))"})
 
   @unittest.expectedFailure
   def test_sum_div_const(self):

tinygrad/codegen/uopgraph.py

@@ -250,6 +250,8 @@ constant_folder = PatternMatcher([
   (UOp.var('x') // UOp.cvar('c'), lambda x,c: x.const(0) if 0 <= x.vmin.arg <= x.vmax.arg < c.arg else None),
   # mod folding
   (UOp.var('x') % UOp.cvar('c'), lambda x,c: x if 0 <= x.vmin.arg <= x.vmax.arg < c.arg else None),
+  # mod reduction
+  (UOp.var('x') % UOp.cvar('c'), lambda x,c: (x-(x.vmin.arg//c.arg)*c.arg)%c if 0 < c.arg <= x.vmin.arg else None),
   # mul -> (sum) -> mod
   ((UOp.cvar('c0')*UOp.var('x')) % UOp.cvar('c1'), lambda x,c0,c1: x*(c0.arg%c1.arg)%c1 if c0.arg >= c1.arg > 0 else None),
   (((UOp.cvar('c')*UOp.var('x'))+UOp.var('x2')) % UOp.cvar('c'), lambda x,c,x2: x2%c),