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2a3d1acd34
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. llvm-svn: 319691 |
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