Improve code generation for constants, 'f' vs no trailing 'f', integer vs non-integer.

MEMO

@@ -65,7 +65,6 @@ To-do
 
 - Scalar insn priority
 
-- What to do about constants in codegen? (...f suffix, complex types)
 
 - If finding a maximum proves troublesome, move parameters into the domain
 
@@ -123,6 +122,9 @@ Future ideas
 Dealt with
 ^^^^^^^^^^
 
+- What to do about constants in codegen? (...f suffix, complex types)
+  -> dealt with by type contexts
+
 - relating to Multi-Domain
   - Make sure that variables that enter into loop bounds are only written
     exactly once. [DONE]

loopy/codegen/bounds.py

@@ -173,7 +173,7 @@ def wrap_in_for_from_constraints(ccm, iname, constraint_bset, stmt):
             from pymbolic import var
             rhs += iname_coeff*var(iname)
             end_conds.append("%s >= 0" %
-                    ccm(cfm(rhs)))
+                    ccm(cfm(rhs), 'i'))
         else: #  iname_coeff > 0
             kind, bound = solve_constraint_for_bound(cns, iname)
             assert kind == ">="
@@ -205,7 +205,7 @@ def wrap_in_for_from_constraints(ccm, iname, constraint_bset, stmt):
         from cgen import For
         from loopy.codegen import wrap_in
         return wrap_in(For,
-                "int %s = %s" % (iname, ccm(start_expr)),
+                "int %s = %s" % (iname, ccm(start_expr, 'i')),
                 " && ".join(end_conds),
                 "++%s" % iname,
                 stmt)

loopy/codegen/instruction.py

@@ -12,11 +12,18 @@ def generate_instruction_code(kernel, insn, codegen_state):
     expr = insn.expression
 
     from loopy.codegen.expression import perform_cast
-    expr = perform_cast(ccm, expr, expr_dtype=ccm.infer_type(expr),
-            target_dtype=kernel.get_var_descriptor(insn.get_assignee_var_name()).dtype)
+    target_dtype = kernel.get_var_descriptor(insn.get_assignee_var_name()).dtype
+    expr_dtype = ccm.infer_type(expr)
+
+    expr = perform_cast(ccm, expr,
+            expr_dtype=expr_dtype,
+            target_dtype=target_dtype)
 
     from cgen import Assign
-    insn_code = Assign(ccm(insn.assignee), ccm(expr))
+    from loopy.codegen.expression import dtype_to_type_context
+    insn_code = Assign(
+            ccm(insn.assignee, prec=None, type_context=None),
+            ccm(expr, prec=None, type_context=dtype_to_type_context(target_dtype)))
     from loopy.codegen.bounds import wrap_in_bounds_checks
     insn_inames = kernel.insn_inames(insn)
     insn_code, impl_domain = wrap_in_bounds_checks(