On Thu, 2005-05-19 at 16:42 +0200, Davide Pozza wrote: > I'd need some help to develop a function, for a new gcc pass, > located after the value range propagation pass. > > I'm working on the last release of gcc 4.1. > > I'd like to have a function that receiving a stmt (that is > a CALL_EXPR) and an index (to specify the position of the > argument), has to return, for the argument specified, the variable > "defined" (i.e. the variable between those obtainable by code like > "FOR_EACH_SSA_TREE_OPERAND (def, ..., stmt, SSA_OP_ALL_DEFS)" ). > The function has to return a NULL_TREE, when there is not a > definition for the given argument. > > The function prototype should be: > static tree get_def_operand(tree stmt, int i); > > > To explain me better, I use an example. > > Supposing to have an fgets call. > > # stdin_12 = V_MAY_DEF <stdin_1>; > # buf_13 = V_MAY_DEF <buf_3>; > # dst_14 = V_MAY_DEF <dst_11>; > [test.c : 10] fgets (&buf, 10, stdin.23_2); > > Calling the get_def_operand for this statement with index 0, the > function has to return the tree corresponding to buf_13.
Uh, don't you mean buf? Or are you trying to match up call arguments with V_MAY_DEF's (if so, you are out of luck, you'll have to do it somewhat like get_call_expr_operands does it, which is to walk each real argument of the call, and see what the associated memory tag is) > > Thanks for the attention! > > Davide
