[gcc r13-1120] xtensa: Document new -mextra-l32r-costs= Xtensa-specific option

[Max Filippov <jcmvbkbc@gcc.gnu.org>]

https://gcc.gnu.org/g:96518f714e3fab53a966a05b8d48011e27c1a718

commit r13-1120-g96518f714e3fab53a966a05b8d48011e27c1a718
Author: Takayuki 'January June' Suwa <jjsuwa_sys3175@yahoo.co.jp>
Date:   Tue Jun 14 12:34:48 2022 +0900

    xtensa: Document new -mextra-l32r-costs= Xtensa-specific option
    
    gcc/ChangeLog:
            * doc/invoke.texi: Document -mextra-l32r-costs= option.

Diff:
---
 gcc/doc/invoke.texi | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 0eab7e4d31b..60b7b5a26bb 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -1474,7 +1474,8 @@ See RS/6000 and PowerPC Options.
 -mauto-litpools  -mno-auto-litpools @gol
 -mtarget-align  -mno-target-align @gol
 -mlongcalls  -mno-longcalls @gol
--mabi=@var{abi-type}}
+-mabi=@var{abi-type} @gol
+-mextra-l32r-costs=@var{cycles}}
 
 @emph{zSeries Options}
 See S/390 and zSeries Options.
@@ -33549,6 +33550,14 @@ by 8 registers on entry so that its arguments are found in registers
 pointer.  Register window is rotated 8 registers back upon return.
 When this version of the ABI is enabled the C preprocessor symbol
 @code{__XTENSA_WINDOWED_ABI__} is defined.
+
+@item -mextra-l32r-costs=@var{n}
+@opindex mextra-l32r-costs
+Specify an extra cost of instruction RAM/ROM access for @code{L32R}
+instructions, in clock cycles.  This affects, when optimizing for speed,
+whether loading a constant from literal pool using @code{L32R} or
+synthesizing the constant from a small one with a couple of arithmetic
+instructions.  The default value is 0.
 @end table
 
 @node zSeries Options