Summary:
The assembler temporary is normally $at ($1) but can be reassigned using
'.set at=$reg'. Regardless of which register is nominated as the assembler
temporary, $at remains $1 when written by the user.
Adds warnings under the following conditions:
* The register nominated as the assembler temporary is used by the user.
* '.set noat' is in effect and $at is used by the user.
Both of these only work for named registers. I have a follow up commit that makes it work for numeric registers as well.
XFAIL set-at-directive.s since it incorrectly tests that $at is redefined by
'.set at=$reg'. Testcases will follow in a separate commit.
Patch by David Chisnall
His work was sponsored by: DARPA, AFRL
Differential Revision: http://llvm-reviews.chandlerc.com/D3167
llvm-svn: 204710
excluding visibility bits.
Mips specific standalone assembler directive "set at".
This directive changes the general purpose register
that the assembler will use when given the symbolic
register name $at.
This does not include negative testing. That will come
in a future patch.
A side affect of this patch recognizes the different
GPR register names for temporaries between old abi
and new abi so a test case for that is included.
Contributer: Vladimir Medic
llvm-svn: 175686
