https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72785
Bug ID: 72785
Summary: [7 Regression] kernel build error since r236831
Product: gcc
Version: 7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: trippels at gcc dot gnu.org
CC: law at gcc dot gnu.org
Target Milestone: ---
Since r236831 I get:
...
LD init/built-in.o
kernel/built-in.o:memremap.c:function update_wall_time: error: undefined
reference to '____ilog2_NaN'
make: *** [Makefile:955: vmlinux] Error 1
markus@x4 linux % cat timekeeping.i
int a, b;
extern int ____ilog2_NaN(void);
void by(void) {
int c = 1;
b = a ?: c;
__builtin_constant_p(b) ? b ? ____ilog2_NaN() : 0 : 0;
}
markus@x4 linux % icc -O2 -c timekeeping.i -S -o - | grep ____ilog2_NaN
markus@x4 linux % clang -O2 -c timekeeping.i -S -o - | grep ____ilog2_NaN
markus@x4 linux % gcc-6 -O2 -c timekeeping.i -S -o - | grep ____ilog2_NaN
markus@x4 linux % gcc-trunk -O2 -c timekeeping.i -S -o - | grep ____ilog2_NaN
jmp ____ilog2_NaN
