SME support routines expect that the reserved bytes of TPIDR2 (bytes
10-15) are zero. This patch ensures that the reserved bytes are cleared
when allocating a new TPIDR2 block.
Refresh of the generic scheduling model to use A510 instead of A55.
Main benefits are to the little core, and introducing SVE scheduling information.
Changes tested on various OoO cores, no performance degradation is seen.
Differential Revision: https://reviews.llvm.org/D156799
We already do this for most cases, with the exception of instructions that
get expanded to function calls (e.g. for lowering operations on fp128
values), in which case we temporarily allocate a lazy-save buffer.
The code that is generated in this case, is however incorrect, as it seems
to pass an incorrect address for the TPIDR2 object to the ZA restore
function. By always allocating the lazy-save buffer once, we avoid this
issue entirely.
The cost is that we also allocate such a buffer when it is not
needed. We could fix that in a follow-up patch, where we remove the
lazy-save buffer when it isn't used.
Reviewed By: paulwalker-arm
Differential Revision: https://reviews.llvm.org/D138208
This fixes a bug in 'allocateLazySaveBuffer' that led to the
buffer pointer being stored to the wrong address.
Reviewed By: david-arm
Differential Revision: https://reviews.llvm.org/D137734
Setting up a lazy-save mechanism around calls is done during SelectionDAG
because calls to intrinsics may be expanded into an actual function call
(e.g. calls to @llvm.cos()), and maintaining an allowed-list in the SMEABI
pass is not feasible.
The approach for conditionally restoring the lazy-save based on the runtime
value of TPIDR2_EL0 is similar to how we handle conditional smstart/smstop.
We create a pseudo-node which gets expanded into a conditional branch and
expands to a call to __arm_tpidr2_restore(%tpidr2_object_ptr).
The lazy-save buffer and TPIDR2 block are only allocated once at the start
of the function. For each call, the TPIDR2 block is initialised, and at
the end of the call, a pseudo node (RestoreZA) is planted.
Patch by Sander de Smalen.
Differential Revision: https://reviews.llvm.org/D133900
When a streaming mode change is (or may be) required for a call, it will
need to restore the original mode after the call, which prevents the use of
tail-call optimization. The same holds true for a call that requires the lazy-save
mechanism to be set up before the call, and possibly restored after.
More details about the SME attributes and design can be found
in D131562.
Reviewed By: aemerson
Differential Revision: https://reviews.llvm.org/D131579
