The second register is the index register and should only be %si or %di if used with a base register. And in that case the base register should be %bp or %bx.
This makes us compatible with gas.
We do still need to support both orders with Intel syntax which uses [bp+si] and [si+bp]
llvm-svn: 335384
(%bp) can't be encoded without a displacement. The encoding is instead used for displacement alone. So a 1 byte displacement of 0 must be used. But if there is an index register we can encode without a displacement.
llvm-svn: 335379
This is not really expected to work right yet. Mostly because we will
still emit the OpSize (0x66) prefix in all the wrong places, along with
a number of other corner cases. Those will all be fixed in the subsequent
commits.
Patch from David Woodhouse.
llvm-svn: 198584
Add some tests to validate correct register selection, including a fix
to an existing test which was requiring the *wrong* output.
Patch from David Woodhouse.
llvm-svn: 198566
