[AtomicExpand][RISCV] Call shouldExpandAtomicRMWInIR before widenPartwordAtomicRMW #80947
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…wordAtomicRMW. This gives the target a chance to keep an atomicrmw op that is smaller than the minimum cmpxchg size. This is needed to support the Zabha extension for RISC-V which provides i8/i16 atomicrmw operations, but does not provide an i8/i16 cmpxchg or LR/SC instructions. This moves the widening until after the target requests LLSC/CmpXChg/MaskedIntrinsic expansion. Once we widen, we call shouldExpandAtomicRMWInIR again to give the target another chance to make a decision about the widened operation. I considered making the targets return AtomicExpansionKind::Expand or a new expansion kind for And/Or/Xor, but that required the targets to special case And/Or/Xor which they weren't currently doing. This should make it easier to implement llvm#80192.
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Drop newline.
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This gives the target a chance to keep an atomicrmw op that is smaller than the minimum cmpxchg size. This is needed to support the Zabha extension for RISC-V which provides i8/i16 atomicrmw operations, but does not provide an i8/i16 cmpxchg or LR/SC instructions.
This moves the widening until after the target requests LLSC/CmpXChg/MaskedIntrinsic expansion. Once we widen, we call shouldExpandAtomicRMWInIR again to give the target another chance to make a decision about the widened operation.
I considered making the targets return AtomicExpansionKind::Expand or a new expansion kind for And/Or/Xor, but that required the targets to special case And/Or/Xor which they weren't currently doing.
This should make it easier to implement #80192.