On 4/10/19 4:51 PM, Segher Boessenkool wrote:
[ Please keep replies on the list. Thanks. ]
On Wed, Apr 10, 2019 at 06:04:30PM +0200, phi gcc wrote:
I can't really change the Makefile so the --no-builtin is not too easy for me.
The pragma seems not work on my gcc
TC$ gcc --version
gcc (Ubuntu 7.3.0-27ubuntu1~18.04) 7.3.0
TC$ echo "#pragma GCC diagnostic ignored \"-Wbuiltin-declaration-mismatch\"
int exp;" | cc -c -x c -
<stdin>:2:5: warning: built-in function 'exp' declared as non-function
Disabling the built-in is far safer than disabling these warnings.
Some optimizations transform calls to library functions made by
the program and recognized as built-ins to those to other functions
that the program never explicitly calls. When an incompatible symbol
with the same name as one of the other built-in functions is defined
in a program, calls to the other built-in will very likely crash.
It ought to be possible to disable built-ins using an attribute
or #pragma, like #pragma GCC optimize, but it doesn't work. If
there isn't a way to do it, filing an enhancement request might
help.
Martin
