https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78562
Bug ID: 78562 Summary: Wrong warning for built-in functions with -flto Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: lto Assignee: unassigned at gcc dot gnu.org Reporter: gjl at gcc dot gnu.org Target Milestone: --- Created attachment 40175 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40175&action=edit lto.c: C test case The attaches test case throws an incorrect warning when compiled with -flto $ avr-gcc -mmcu=atmega8 lto.c -Os -flto <built-in>: warning: type of '__builtin_avr_absr' does not match original declaration [-Wlto-type-mismatch] <built-in>: note: return value type mismatch <built-in>: note: '__builtin_avr_abshk' was previously declared here <built-in>: note: code may be misoptimized unless -fno-strict-aliasing is used Using GCC from v7 trunk Last Changed Rev: 242822 Last Changed Date: 2016-11-24 10:45:01 +0100 (Do, 24 Nov 2016) GCC configured as $ ../../gcc.gnu.org/trunk/configure --target=avr --prefix=/local/gnu/install/gcc-7 --disable-shared --disable-nls --with-dwarf2 --enable-target-optspace=yes --with-gnu-as --with-gnu-ld --enable-checking=release --enable-languages=c,c++