-- See also Note [Take care] below
= do { id <- newId FSLIT("a") (exprType rhs)
; completeNonRecX env False id id rhs $ \ env ->
- thing_inside env (Cast (Var id) co) }
+ thing_inside env (Cast (substExpr env (Var id)) co) }
mkAtomicArgsE env is_strict rhs thing_inside
| (Var fun, args) <- collectArgs rhs, -- It's an application
| otherwise
= do { arg_id <- newId FSLIT("a") arg_ty
; completeNonRecX env False {- pessimistic -} arg_id arg_id arg $ \env ->
- go env (App fun (Var arg_id)) args }
+ go env (App fun (substExpr env (Var arg_id))) args }
-- Note [Take care]:
- -- This is sightly delicate. If completeNonRecX was to do a postInlineUnconditionally
+ -- If completeNonRecX was to do a postInlineUnconditionally
-- (undoing the effect of introducing the let-binding), we'd find arg_id had
- -- no binding. The exprIsTrivial is the only time that'll happen, though.
+ -- no binding; hence the substExpr. This happens if we see
+ -- C (D x `cast` g)
+ -- Then we start by making a variable a1, thus
+ -- let a1 = D x `cast` g in C a1
+ -- But then we deal with the rhs of a1, getting
+ -- let a2 = D x, a1 = a1 `cast` g in C a1
+ -- And now the preInlineUnconditionally kicks in, and we substitute for a1
+
where
arg_ty = exprType arg
no_float_arg = not is_strict && (isUnLiftedType arg_ty) && not (exprOkForSpeculation arg)