Rename MIR_VA_STACK_ARG into MIR_VA_BLOCK_ARG in MIR.md.
* The first insn saves the stack pointer in the operand
* The second insn restores stack pointer from the operand
-### MIR_VA_START, MIR_VA_ARG, MIR_VA_STACK_ARG, and MIR_VA_END insns
+### MIR_VA_START, MIR_VA_ARG, MIR_VA_BLOCK_ARG, and MIR_VA_END insns
* These insns are only for variable number arguments functions
* `MIR_VA_START` and `MIR_VA_END` have one input operand, an address
of va_list structure (see C stdarg.h for more details). Unlike C
* `MIR_VA_ARG` takes va_list and any memory operand and returns
address of the next argument in the 1st insn operand. The memory
operand type defines the type of the argument
- * `MIR_VA_STACK_ARG` takes va_list and integer operand and returns
+ * `MIR_VA_BLOCK_ARG` takes va_list and integer operand and returns
address of the next argument passed as a block argument
of the size given by the integer operand
* va_list operand can be memory with undefined type. In this case
