David Greene 8ad4c00c00 Have TableGen emit setSubgraphColor calls under control of a -gen-debug
flag.  Then in a debugger developers can set breakpoints at these calls
to see waht is about to be selected and what the resulting subgraph
looks like.  This really helps when debugging instruction selection.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58278 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-27 21:56:29 +00:00
..
2008-09-26 04:40:32 +00:00

***

add gcc builtins for alpha instructions


***

custom expand byteswap into nifty 
extract/insert/mask byte/word/longword/quadword low/high
sequences

***

see if any of the extract/insert/mask operations can be added

***

match more interesting things for cmovlbc cmovlbs (move if low bit clear/set)

***

lower srem and urem

remq(i,j):  i - (j * divq(i,j)) if j != 0
remqu(i,j): i - (j * divqu(i,j)) if j != 0
reml(i,j):  i - (j * divl(i,j)) if j != 0
remlu(i,j): i - (j * divlu(i,j)) if j != 0

***

add crazy vector instructions (MVI):

(MIN|MAX)(U|S)(B8|W4) min and max, signed and unsigned, byte and word
PKWB, UNPKBW pack/unpack word to byte
PKLB UNPKBL pack/unpack long to byte
PERR pixel error (sum accross bytes of bytewise abs(i8v8 a - i8v8 b))

cmpbytes bytewise cmpeq of i8v8 a and i8v8 b (not part of MVI extentions)

this has some good examples for other operations that can be synthesised well 
from these rather meager vector ops (such as saturating add).
http://www.alphalinux.org/docs/MVI-full.html