http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51931
Bug #: 51931
Summary: No support for MIPS16 long branches
Classification: Unclassified
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: rsand...@gcc.gnu.org
The MIPS port doesn't detect when MIPS16 branches are out of range,
and it doesn't provide the same kind of "branch around jump" fallback
as it does for non-MIPS16 code.
This has always been a problem, and shows up as a long-standing failure
in gcc.c-torture/compile/20001226-1.c and g++.dg/opt/longbranch1.C.
I've thought about various fixes, such as saving a MIPS16 register
to $1 before using it as a scratch, then restoring it in the branch
delay slot. But there are various ugly cases.
The bug only triggers for very large functions and at least these days
there's a workaround: add __attribute__((nomips16)).
