> diff --git a/gcc/ipa-pure-const.c b/gcc/ipa-pure-const.c
> index 09ca3590039..0406d5588d2 100644
> --- a/gcc/ipa-pure-const.c
> +++ b/gcc/ipa-pure-const.c
> @@ -910,7 +910,8 @@ malloc_candidate_p (function *fun, bool ipa)
> #define DUMP_AND_RETURN(reason) \
> { \
> if (dump_file && (dump_flags & TDF_DETAILS)) \
> - fprintf (dump_file, "%s", (reason)); \
> + fprintf (dump_file, "\n%s is not a malloc candidate, reason: %s\n", \
> + (node->name()), (reason)); \
> return false; \
> }
>
> @@ -961,11 +962,14 @@ malloc_candidate_p (function *fun, bool ipa)
> for (unsigned i = 0; i < gimple_phi_num_args (phi); ++i)
> {
> tree arg = gimple_phi_arg_def (phi, i);
> + if (arg == null_pointer_node)
> + continue;
I think you want operand_equal_p here and also check for
flag_delete_null_pointer_checks
because otherwise 0 can be legal memory block addrss.
> +
> if (TREE_CODE (arg) != SSA_NAME)
> - DUMP_AND_RETURN("phi arg is not SSA_NAME.")
> - if (!(arg == null_pointer_node || check_retval_uses (arg, phi)))
> - DUMP_AND_RETURN("phi arg has uses outside phi"
> - " and comparisons against 0.")
> + DUMP_AND_RETURN ("phi arg is not SSA_NAME.");
> + if (!check_retval_uses (arg, phi))
> + DUMP_AND_RETURN ("phi arg has uses outside phi"
> + " and comparisons against 0.")
So the case of phi(0,0) is not really correctness issue just missed
optimization?
I would still add code to handle it (it is easy).
Do you also handle a case where parameter of phi is another phi?
Honza
>
> gimple *arg_def = SSA_NAME_DEF_STMT (arg);
> gcall *call_stmt = dyn_cast<gcall *> (arg_def);
> diff --git a/gcc/testsuite/gcc.dg/ipa/pr83648.c
> b/gcc/testsuite/gcc.dg/ipa/pr83648.c
> new file mode 100644
> index 00000000000..03b45de671b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/ipa/pr83648.c
> @@ -0,0 +1,9 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-local-pure-const-details" } */
> +
> +void *g(unsigned n)
> +{
> + return n ? __builtin_malloc (n) : 0;
> +}
> +
> +/* { dg-final { scan-tree-dump "Function found to be malloc: g"
> "local-pure-const1" } } */
