[llvm] [GISel][RISCV]Implement indirect parameter passing for large scalars (PR #95429)

[Sergei Barannikov via llvm-commits]

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@@ -790,6 +804,36 @@ bool CallLowering::handleAssignments(ValueHandler &Handler,
       CCValAssign &VA = ArgLocs[j + Idx];
       const ISD::ArgFlagsTy Flags = Args[i].Flags[Part];
 
+      // We found an indirect parameter passing and we are at the first part of
+      // the value being passed. In this case copy the incoming pointer into a
+      // virtual register so later we can load it.
+      if (VA.getLocInfo() == CCValAssign::Indirect && Flags.isSplit()) {
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s-barannikov wrote:

In p4 we can decide that one register is enough, in which case isSplit will be false.
This is probably not applicable to RISC-V, but this is a generic code and should support such scenario.
If this is not going to be supported in this patch, I'd expect a fatal error if isSplit is false when Indirect is set.


https://github.com/llvm/llvm-project/pull/95429