The concept of G_GLOBAL_VALUE is nice and simple, but always using it as the
representation for global var addressing until selection time creates some
problems in optimizing accesses in certain code/relocation models.
The problem comes from trying to optimize adrp -> add -> load/store sequences
in the most common "small" code model. These accesses can be optimized into an
adrp -> load with the add offset being folded into the load's immediate field.
If we try to keep all global var references as a single generic instruction
then by the time we get to the complex operand trying to match these, we end up
generating an adrp at the point of use. The real issue here is that we don't
have any form of CSE during selection, so the code size will bloat from many
redundant adrp's.
This patch custom legalizes small code mode non-GOT G_GLOBALs into target ADRP
and a new "target specific generic opcode" G_ADD_LOW. We also teach the
localizer to localize these instructions via the custom hook that was added
recently. Finally, the complex pattern for indexed loads/stores is extended to
try to fold these G_ADD_LOW instructions into the load immediate.
On -O0 CTMark, we see a 0.8% geomean code size improvement. We should also see
some minor performance improvements too.
Differential Revision: https://reviews.llvm.org/D78465
Add a GISelPredicateCode to the stxr_* PatFrags in AArch64InstrAtomics.td.
This allows us to select these intrinsics.
Differential Revision: https://reviews.llvm.org/D65779
llvm-svn: 370382
Remove manual selection code for this intrinsic and use a GISelPredicateCode
instead.
This allows us to fully select this intrinsic without any tricky custom C++
matching.
Differential Revision: https://reviews.llvm.org/D65780
llvm-svn: 370380
Same thing as D66897, but for ldxr.* instead. Add a GISelPredicateCode to the
ldxr_* definitions, which allows us to import them.
Add select-ldxr-intrin.mir, and update arm64-ldxr-stxr.ll.
Differential Revision: https://reviews.llvm.org/D66898
llvm-svn: 370378
Add a GISelPredicateCode to ldaxr_*. This allows us to import the patterns for
@llvm.aarch64.ldaxr.*, and thus select them.
Add `isLoadStoreOfNumBytes` for the GISelPredicateCode, since each of these
intrinsics involves the same check.
Add select-ldaxr-intrin.mir, and update arm64-ldxr-stxr.ll.
Differential Revision: https://reviews.llvm.org/D66897
llvm-svn: 370377
Add partial instruction selection for intrinsics like this:
```
declare i32 @llvm.aarch64.stlxr(i64, i32*)
```
(This only handles the case where a G_ZEXT is feeding the intrinsic.)
Also make sure that the added store instruction actually has the memory op from
the original G_STORE.
Update select-stlxr-intrin.mir and arm64-ldxr-stxr.ll.
Differential Revision: https://reviews.llvm.org/D65355
llvm-svn: 367163
This adds partial instruction selection support for llvm.aarch64.stlxr. It also
factors out selection for G_INTRINSIC_W_SIDE_EFFECTS into its own function. The
new function removes the restriction that the intrinsic ID on the
G_INTRINSIC_W_SIDE_EFFECTS be on operand 0.
Also add a test, and add a GISel line to arm64-ldxr-stxr.ll.
Differential Revision: https://reviews.llvm.org/D60100
llvm-svn: 357518
This commit starts with a "git mv ARM64 AArch64" and continues out
from there, renaming the C++ classes, intrinsics, and other
target-local objects for consistency.
"ARM64" test directories are also moved, and tests that began their
life in ARM64 use an arm64 triple, those from AArch64 use an aarch64
triple. Both should be equivalent though.
This finishes the AArch64 merge, and everyone should feel free to
continue committing as normal now.
llvm-svn: 209577
Amara Emerson