[llvm] [VP][RISCV] Add a vp.load.ff intrinsic for fault only first load. (PR #128593)

[Luke Lau via llvm-commits]

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@@ -587,6 +587,12 @@ VP_PROPERTY_FUNCTIONAL_OPC(Load)
 VP_PROPERTY_FUNCTIONAL_INTRINSIC(masked_load)
 END_REGISTER_VP(vp_load, VP_LOAD)
 
+BEGIN_REGISTER_VP_INTRINSIC(vp_load_ff, 1, 2)
+// val,chain = VP_LOAD_FF chain,base,mask,evl
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lukel97 wrote:

I was going to ask why this doesn't have an offset operand like the others so it could inherit from `VPBaseLoadStoreSDNode`, but then I realised we don't use the offset in RISCVISelLowering for regular vp.load/store.

SelectionDAGBuilder doesn't set it, I think it's always undef. Not for this PR but can we remove it?

https://github.com/llvm/llvm-project/pull/128593