[Bug jit/122443] Huge memory usage in walk_tree_1 with deeply nested expressions

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122443

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
And instead of ` build1 (CONVERT_EXPR,` use fold_convert ...