https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79778
Bug ID: 79778
Summary: [7 regression] missed optimization causes linux kernel
build failure since r245135
Product: gcc
Version: 7.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: arnd at linaro dot org
Target Milestone: ---
With the latest gcc-7.0.1 snapshot, I got lots of these failures building
random linux kernel configurations:
kernel/built-in.o: In function `update_wall_time':
(.text+0x418a0): undefined reference to `____ilog2_NaN'
Variations of this symptom have happened in the past, e.g. pr36359, pr78653,
pr78879, pr49642, pr72785, but for all I can tell, this one is slightly
different again.
I have bisected the problem to r245135, and have confirmed that reverting this
on top of r245806 (today's HEAD commit) fixes the problem for builds that ran
into this on my test box.
