[Bug target/99581] [11 Regression] internal compiler error: during RTL pass: final - void QTWTF::TCMalloc_PageHeap::scavengerThread() since r11-7526

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99581

--- Comment #5 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Thanks Vladimir.  It is indeed a problem in LRA (or triggered by it).
We have
    8: {[r121:DI+low(unspec[`*.LANCHOR0',%2:DI]
47+0x92a4)]=asm_operands;clobber

so this is an offset that is too big for a machine instruction, those can take
-32768..32767.

Changing the constraint to "m" you get in LRA
    Inserting insn reload before:
   13: r121:DI=high(unspec[`*.LANCHOR0',%2:DI] 47+0x92a4)

but this doesn't happen if you keep it "o", and it dies later.