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On 11/7/21 4:31 PM, Martin Sebor wrote:
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On 10/23/21 5:06 PM, Martin Sebor wrote:
On 10/4/21 3:37 PM, Jason Merrill wrote:
On 10/4/21 14:42, Martin Sebor wrote:
While resolving the recent -Waddress enhancement request (PR
PR102103) I came across a 2007 problem report about GCC 4 having
stopped warning for using the address of inline functions in
equality comparisons with null. With inline functions being
commonplace in C++ this seems like an important use case for
the warning.
The change that resulted in suppressing the warning in these
cases was introduced inadvertently in a fix for PR 22252.
To restore the warning, the attached patch enhances
the decl_with_nonnull_addr_p() function to return true also for
weak symbols for which a definition has been provided.
I think you probably want to merge this function with
fold-const.c:maybe_nonzero_address, which already handles more cases.
maybe_nonzero_address() doesn't behave quite like
decl_with_nonnull_addr_p() expects and I'm reluctant to muck
around with the former too much since it's used for codegen,
while the latter just for warnings. (There is even a case
where the functions don't behave the same, and would result
in different warnings between C and C++ without some extra
help.)
So in the attached revision I just have maybe_nonzero_address()
call decl_with_nonnull_addr_p() and then refine the failing
(or uncertain) cases separately, with some overlap between
them.
Since I worked on this someone complained that some instances
of the warning newly enhanced under PR102103 aren't suppresed
in code resulting from macro expansion. Since it's trivial,
I include the fix for that report in this patch as well.
Tested on x86_64-linux.
Martin
