[Bug target/63312] FAIL: gcc.dg/torture/float128-exact-underflow.c -O0 execution test

[sch...@linux-m68k.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63312

--- Comment #2 from Andreas Schwab <sch...@linux-m68k.org> ---
This fixes the test for all opt levels, no regressions.