Re: Proposed targets to deprecate for 3.4

["Zack Weinberg" <zack at codesourcery dot com>]

Nathanael, are you interested in coordinating the development of the
obsoleted targets list for this cycle?  I'll be quite happy to let you
do it. ;-)

(Note preferred terminology - "obsoleted" not "deprecated")

You might find this chart of interest.  I was meaning to follow it up
with a similar chart of properties for individual targets but I ran
out of spare time.

zw

--- arch-obs-criteria.txt ---

I've begun to compile a giant table of criteria for deciding whether
or not any given architecture should be preserved.  The table lists
desirable characteristics for all architectures supported by gcc.
Each characteristic has a unique letter.  In all cases, a letter
appearing is the desirable case; no letter is the undesirable case;
and a question mark means I don't know whether the architecture has
the characteristic or not.

Characteristics describing fundamental properties of the architecture
or target use CAPITAL LETTERS; characteristics describing properties
of the GCC port to that architecture or target use small letters.

Yes, many of these things are quite trivial.

Architectures are identified by their gcc/config subdirectory, *not*
their CPU field in config.guess output.

Architecture characteristic key
-------------------------------
H       A hardware implementation exists.
M       A hardware implementation is currently being manufactured.
S       A Free simulator exists.
L       Integer registers are at least 32 bits wide.
Q       Integer registers are at least 64 bits wide.
N       Memory is byte addressable and bytes are eight bits.
F       Floating point arithmetic is supported
        (not necessarily by all implementations)
I       IEEE floating point is supported
        (possibly with software assistance for full conformance)
C       Architecture does not have a single condition code register.
B       Architecture does not have delay slots.
D       Architecture has a stack that grows downward.

l       Port can use ILP32 mode integer arithmetic.
q       Port can use LP64 mode integer arithmetic.
r       Port can switch between ILP32 and LP64 at runtime.
        (Not necessarily supported by all subtargets.)
c       Port does not use cc0.
p       Port does not use define_peephole.
f       Port defines prologue and/or epilogue RTL expanders.
g       Port does not define TARGET_ASM_FUNCTION_(PRO|EPI)LOGUE.
m       Port uses define_constants.
b       Port does not use '"* ..."' notation for output template code.
d       Port uses DFA scheduler descriptions.
h       Port does not contain old scheduler descriptions.
a       Port generates multiple inheritance thunks using
        TARGET_ASM_OUTPUT_MI(_VCALL)_THUNK.
t       All insns either produce exactly one assembly instruction, or
        trigger a define_split.
e       <arch>-elf is a supported target.
s       <arch>-elf is the correct target to use with the simulator
        in /cvs/src.

         | Characteristics
Target   | HMSLQNFICBD lqrcpfgmbdhates
---------+----------------------------
alpha    | H??LQNFICBD lq cpfgmbdha
arc      | ???L N    D l  cp        e
arm      | HMSL NFI BD l  c f m dha es
avr      | H??  N   BD           h  e
c4x      | H??L  F     l  c fgm    t
cris     | ???L N    D l         ha e
d30v     | ??SL N  CBD l  cpf       es
dsp16xx  | ???      B
fr30     | ??SL N    D l  c fg   h tes
frv      | ??SL NFI  D l  cpf m dha es
h8300    | ??SL N   BD l   pf m  h  e
i370     | H ?L NF  B  l   p     h
i386     | HM?LQNFI BD lq cpf m d a e
i860     | H ?L NFI BD l   p  m  h
i960     | H SL NFI B  l  c       a
ia64     | HM?LQNFICBD lqrcpf m dha e
ip2k     | ???  N   BD         b h  e
iq2000   | ???L N  C D l  cpfgm    te
m32r     | ??SL N   BD l  c f       es
m68hc11  | ??S  N   BD      f m  h tes
m68k     | HM?L NFI BD l      m  ha e
mcore    | H?SL N   BD l  c fg      es
mips     | HMSLQNFIC D lqrc f mbd   es
mmix     |   SLQNFICBD lq cpf mb ha
mn10300  | ??SL NFI BD l    fgm  h  es
ns32k    | H ?L NFI BD l         h
pa       | HM?LQNFIC   lqrc f   dha
pdp11    | H ?  NF  BD     p     h
rs6000   | HMSLQNFI BD lqrc f m dha e
s390     | HM?LQNFI BD lqrcpfgmbd a
sh       | HMSLQNFIC D lqrc f m d a e
sparc    | HMSLQNFI  D lqrc f mbdha e
stormy16 | ???  N  CB     cpf    hate
v850     | ??SL N   BD l   pfg      es
vax      | H ?L NF  BD l   pf m  ha
xtensa   | HM?L NFICBD l  cpf mb    e