[gcc(refs/vendors/riscv/heads/gcc-13-with-riscv-opts)] doc: Add doc for RISC-V Operand Modifiers

[gcc(refs/vendors/riscv/heads/gcc-13-with-riscv-opts)] doc: Add doc for RISC-V Operand Modifiers

[Jeff Law]

https://gcc.gnu.org/g:2a7540f86e3bd7df29785b62167752fb33ab246f

commit 2a7540f86e3bd7df29785b62167752fb33ab246f
Author: Kito Cheng <kito.cheng@sifive.com>
Date:   Mon Jul 10 21:57:36 2023 +0800

    doc: Add doc for RISC-V Operand Modifiers
    
    Document `z` and `i` operand modifiers, we have much more modifiers
    other than those two, but they are the only two implement on both
    GCC and LLVM, consider the compatibility I would like to document those
    two first, and then review other modifiers later to see if any other should
    expose and implement on RISC-V LLVM too.
    
    gcc/ChangeLog:
    
            * doc/extend.texi (RISC-V Operand Modifiers): New.

Diff:
---
 gcc/doc/extend.texi | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index a4c5fda9e71..0f5aa1a7a4b 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -11435,6 +11435,16 @@ The list below describes the supported modifiers and their effects for LoongArch
 @item @code{z} @tab Print the operand in its unmodified form, followed by a comma.
 @end multitable
 
+@anchor{riscvOperandmodifiers}
+@subsubsection RISC-V Operand Modifiers
+
+The list below describes the supported modifiers and their effects for RISC-V.
+
+@multitable @columnfractions .10 .90
+@headitem Modifier @tab Description
+@item @code{z} @tab Print ''@code{zero}'' instead of 0 if the operand is an immediate with a value of zero.
+@item @code{i} @tab Print the character ''@code{i}'' if the operand is an immediate.
+@end multitable
 
 @lowersections
 @include md.texi