Add comment about passign 32-bit unsigned integers as vararg.
Copyright (C) 2020-2021 Vladimir Makarov <vmakarov.gcc@gmail.com>.
*/
+/* In MIR generated code unsigned 32-bit values are zero extended but
+ passing/returning such value is signed extended (which is their
+ riscv ABI representation).
+
+ In theory we should pass vararg unsigned as sign extended according
+ to ABI but gcc/clang va_arg code do the correct sign extension
+ anyway. So we can ignore sign extension for integer vararg
+ arguments. */
+
/* ??? TODO: o compressed riscv
o register allocation order for more compressed code
o implement generation for FLEN=128
