cranelift: Fix implicit pointer argument register use (#5301)

* Fix arg handling to write to VRegs instead of physical regs

* Make is_included_in_clobbers required, and handle Args on x64 and riscv64

cranelift/codegen/src/isa/aarch64/inst/mod.rs

@@ -1142,6 +1142,7 @@ impl MachInst for Inst {
         // See the note in [crate::isa::aarch64::abi::is_caller_save_reg] for
         // more information on this ABI-implementation hack.
         match self {
+            &Inst::Args { .. } => false,
             &Inst::Call { ref info } => info.caller_callconv != info.callee_callconv,
             &Inst::CallInd { ref info } => info.caller_callconv != info.callee_callconv,
             _ => true,

cranelift/codegen/src/isa/riscv64/inst/mod.rs

@@ -657,7 +657,10 @@ impl MachInst for Inst {
     }
 
     fn is_included_in_clobbers(&self) -> bool {
-        true
+        match self {
+            &Inst::Args { .. } => false,
+            _ => true,
+        }
     }
 
     fn is_args(&self) -> bool {

cranelift/codegen/src/isa/s390x/inst/mod.rs

@@ -1109,6 +1109,7 @@ impl MachInst for Inst {
         // half-caller-save, half-callee-save SysV ABI for some vector
         // registers.
         match self {
+            &Inst::Args { .. } => false,
             &Inst::Call { ref info, .. } => info.caller_callconv != info.callee_callconv,
             &Inst::CallInd { ref info, .. } => info.caller_callconv != info.callee_callconv,
             _ => true,

cranelift/codegen/src/isa/x64/inst/mod.rs

@@ -2236,6 +2236,13 @@ impl MachInst for Inst {
         }
     }
 
+    fn is_included_in_clobbers(&self) -> bool {
+        match self {
+            &Inst::Args { .. } => false,
+            _ => true,
+        }
+    }
+
     fn is_args(&self) -> bool {
         match self {
             Self::Args { .. } => true,