This patch splits atomics out of the generic G_LOAD/G_STORE and into their own
G_ATOMIC_LOAD/G_ATOMIC_STORE. This is a pragmatic decision rather than a
necessary one. Atomic load/store has little in implementation in common with
non-atomic load/store. They tend to be handled very differently throughout the
backend. It also has the nice side-effect of slightly improving the common-case
performance at ISel since there's no longer a need for an atomicity check in the
matcher table.
All targets have been updated to remove the atomic load/store check from the
G_LOAD/G_STORE path. AArch64 has also been updated to mark
G_ATOMIC_LOAD/G_ATOMIC_STORE legal.
There is one issue with this patch though which also affects the extending loads
and truncating stores. The rules only match when an appropriate G_ANYEXT is
present in the MIR. For example,
(G_ATOMIC_STORE (G_TRUNC:s16 (G_ANYEXT:s32 (G_ATOMIC_LOAD:s16 X))))
will match but:
(G_ATOMIC_STORE (G_ATOMIC_LOAD:s16 X))
will not. This shouldn't be a problem at the moment, but as we get better at
eliminating extends/truncates we'll likely start failing to match in some
cases. The current plan is to fix this in a patch that changes the
representation of extending-load/truncating-store to allow the MMO to describe
a different type to the operation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319691 91177308-0d34-0410-b5e6-96231b3b80d8
G_ATOMICRMW_* is generally legal on AArch64. The exception is G_ATOMICRMW_NAND.
G_ATOMIC_CMPXCHG_WITH_SUCCESS needs to be lowered to G_ATOMIC_CMPXCHG with an
external comparison.
Note that IRTranslator doesn't generate these instructions yet.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319466 91177308-0d34-0410-b5e6-96231b3b80d8
The IRTranslator cannot generate these instructions at the moment so there's no
issue with not having implemented ISel for them yet. D40092 will add
G_ATOMIC_CMPXCHG_WITH_SUCCESS and G_ATOMICRMW_* to the IRTranslator and a
further patch will add support for lowering G_ATOMIC_CMPXCHG_WITH_SUCCESS into
G_ATOMIC_CMPXCHG with an external success check via the `Lower` action.
The separation of G_ATOMIC_CMPXCHG_WITH_SUCCESS and G_ATOMIC_CMPXCHG is
to import SelectionDAG rules while still supporting targets that prefer to
custom lower the original LLVM-IR-like operation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319216 91177308-0d34-0410-b5e6-96231b3b80d8
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318490 91177308-0d34-0410-b5e6-96231b3b80d8
