--- a/gcc/config/avr/avr.opt	Sun Aug 21 07:07:55 2011 +0900
+++ b/gcc/config/avr/avr.opt	Fri Oct 27 22:46:09 2017 +0900
@@ -1,6 +1,6 @@
 ; Options for the ATMEL AVR port of the compiler.
 
-; Copyright (C) 2005, 2007, 2008, 2010 Free Software Foundation, Inc.
+; Copyright (C) 2005-2017 Free Software Foundation, Inc.
 ;
 ; This file is part of GCC.
 ;
@@ -20,22 +20,49 @@
 
 mcall-prologues
 Target Report Mask(CALL_PROLOGUES)
-Use subroutines for function prologues and epilogues
+Use subroutines for function prologues and epilogues.
 
 mmcu=
-Target RejectNegative Joined Var(avr_mcu_name) Init("avr2")
--mmcu=MCU	Select the target MCU
+Target RejectNegative Joined Var(avr_mmcu) MissingArgError(missing device or architecture after %qs)
+-mmcu=MCU	Select the target MCU.
+
+mgas-isr-prologues
+Target Report Var(avr_gasisr_prologues) UInteger Init(0)
+Allow usage of __gcc_isr pseudo instructions in ISR prologues and epilogues.
+
+mn-flash=
+Target RejectNegative Joined Var(avr_n_flash) UInteger Init(-1)
+Set the number of 64 KiB flash segments.
+
+mskip-bug
+Target Report Mask(SKIP_BUG)
+Indicate presence of a processor erratum.
+
+mrmw
+Target Report Mask(RMW)
+Enable Read-Modify-Write (RMW) instructions support/use.
 
 mdeb
 Target Report Undocumented Mask(ALL_DEBUG)
 
+mlog=
+Target RejectNegative Joined Undocumented Var(avr_log_details)
+
+mshort-calls
+Target Report RejectNegative Mask(SHORT_CALLS)
+Use RJMP / RCALL even though CALL / JMP are available.
+
 mint8
 Target Report Mask(INT8)
-Use an 8-bit 'int' type
+Use an 8-bit 'int' type.
 
 mno-interrupts
 Target Report RejectNegative Mask(NO_INTERRUPTS)
-Change the stack pointer without disabling interrupts
+Change the stack pointer without disabling interrupts.
+
+mbranch-cost=
+Target Report Joined RejectNegative UInteger Var(avr_branch_cost) Init(0)
+Set the branch costs for conditional branch instructions.  Reasonable values are small, non-negative integers.  The default branch cost is 0.
 
 morder1
 Target Report Undocumented Mask(ORDER_1)
@@ -43,18 +70,47 @@
 morder2
 Target Report Undocumented Mask(ORDER_2)
 
-mshort-calls
-Target Report Mask(SHORT_CALLS)
-Use rjmp/rcall (limited range) on >8K devices
-
 mtiny-stack
 Target Report Mask(TINY_STACK)
-Change only the low 8 bits of the stack pointer
+Change only the low 8 bits of the stack pointer.
 
 mrelax
 Target Report
-Relax branches
+Relax branches.
 
 mpmem-wrap-around
 Target Report
 Make the linker relaxation machine assume that a program counter wrap-around occurs.
+
+maccumulate-args
+Target Report Mask(ACCUMULATE_OUTGOING_ARGS)
+Accumulate outgoing function arguments and acquire/release the needed stack space for outgoing function arguments in function prologue/epilogue.  Without this option, outgoing arguments are pushed before calling a function and popped afterwards.  This option can lead to reduced code size for functions that call many functions that get their arguments on the stack like, for example printf.
+
+mstrict-X
+Target Report Var(avr_strict_X) Init(0)
+When accessing RAM, use X as imposed by the hardware, i.e. just use pre-decrement, post-increment and indirect addressing with the X register.  Without this option, the compiler may assume that there is an addressing mode X+const similar to Y+const and Z+const and emit instructions to emulate such an addressing mode for X.
+
+;; For rationale behind -msp8 see explanation in avr.h.
+msp8
+Target Report RejectNegative Var(avr_sp8) Init(0)
+The device has no SPH special function register. This option will be overridden by the compiler driver with the correct setting if presence/absence of SPH can be deduced from -mmcu=MCU.
+
+Waddr-space-convert
+Warning C Report Var(avr_warn_addr_space_convert) Init(0)
+Warn if the address space of an address is changed.
+
+Wmisspelled-isr
+Warning C C++ Report Var(avr_warn_misspelled_isr) Init(1)
+Warn if the ISR is misspelled, i.e. without __vector prefix. Enabled by default.
+
+mfract-convert-truncate
+Target Report Mask(FRACT_CONV_TRUNC)
+Allow to use truncation instead of rounding towards zero for fractional fixed-point types.
+
+mabsdata
+Target Report Mask(ABSDATA)
+Assume that all data in static storage can be accessed by LDS / STS.  This option is only useful for reduced Tiny devices.
+
+nodevicelib
+Driver Target Report RejectNegative
+Do not link against the device-specific library lib<MCU>.a.