Print AST tree

[Andy via Gcc-help <gcc-help@xxxxxxxxxxx>]

Which option is to print AST?
I have b.c:
int *fun0_1(){}

gcc -std=c90 -pedantic-errors -fdump-ast b.c
- not recognized -fdump-ast

gcc -std=c90 -pedantic-errors -fdump-tree-ast b.c
- not recognized -fdump-tree-ast

gcc -std=c90 -pedantic-errors -fdump-tree-all b.c
- generates many files