More progress on WhileOp codegen

rewrite-test/jit/if-else/if-else.py

@@ -0,0 +1,49 @@
+import triton
+
+@triton.jit
+def if_else(lb, ub, value):
+  if value > lb:
+    a = 0.0
+  else:
+    a = 1.0
+  c = a + a
+
+@triton.jit
+def only_if(lb, ub, value):
+  a = -1.0
+  if value > lb:
+    a = 0.0
+  c = a + a
+
+@triton.jit
+def only_if_invalid(lb, ub, value):
+  if value > lb:
+    a = 0.0
+  c = a + a
+
+@triton.jit
+def nested_if(lb, ub, value):
+  if value > lb:
+    if value < ub:
+      a = 2.0
+    else:
+      a = 1.0
+  else:
+    a = 0.0
+  c = a + a
+
+
+mod_if_else, ctx_if_else = if_else.compile_to_ttir(2, 4, 3, grid=(1,))
+mod_if_else.dump()
+
+mod_only_if, ctx_only_if = only_if.compile_to_ttir(2, 4, 3, grid=(1,))
+mod_only_if.dump()
+
+try:
+  mod_only_if_invalid, ctx_only_if = only_if_invalid.compile_to_ttir(2, 4, 3, grid=(1,))
+  mod_only_if_invalid.dump()
+except:
+  print('value error')
+
+mod_nested_if, ctx_nested_if = nested_if.compile_to_ttir(2, 4, 3, grid=(1,))
+mod_nested_if.dump()