[PATCH 0/9] S/390 rework shift count handling

[Andreas Krebbel <krebbel at linux dot vnet dot ibm dot com>]

On S/390 we have address style shift counts.  So it is possible to
have a reg + const_int shift count.  To address this it appeared to be
convenient to really handle this as address operand.  For that reason
the "Y" constraint used for shift counts is an extra memory
constraint.  Unfortunately a shift count is not necessarily Pmode.  So
even when compiling for 64 bit we had to allow SImode addresses for Y.
Since all extra memory constraints go through s390_decompose_address
we had to unconditionally enable SImode addresses everywhere:

https://gcc.gnu.org/ml/gcc-patches/2006-03/msg01495.html

Unfortunately this seems to cause some trouble in situations not
entirely clear to me yet:

https://gcc.gnu.org/ml/gcc/2015-05/msg00305.html

This patchset fixes this by getting rid of SImode - "Y" combinations
in our machine description.  To prevent us from losing performance in
situations where an reg + const_int can really be used as shift count
we have to make it explicit in the RTL patterns.  This unfortunately
requires us to duplicate a lot of patterns.  To compensate for that
I'm using the define_subst mechanism to keep the overhead limited.  In
fact the patchset reduces the number of lines in the md files.

I've tested the whole patchset with various CPU levels on s390 and
s390x.  No regressions.

Patch 1 is the only common code change which fixes a problem with the
renumbering of operands when performing substitutions.

While I only need a formal approval for patch 1 comments regarding the
other patches are welcome as well.

Ok to apply?

Bye,

-Andreas-

Andreas Krebbel (9):
  gensupport: Fix define_subst operand renumbering.
  S/390: Add disabled insn attribute
  S/390: Get rid of Y constraint in rotate patterns.
  S/390: Get rid of Y constraint in left and logical right shift
    patterns.
  S/390: Get rid of Y constraint in arithmetic right shift patterns.
  S/390: Get rid of Y constraint in tabort.
  S/390: Get rid of Y constraint in vector.md.
  S/390: Use define_subst for the setmem patterns.
  S/390: Disallow SImode in s390_decompose_address

 gcc/config/s390/predicates.md |  31 +++
 gcc/config/s390/s390.c        |   8 +-
 gcc/config/s390/s390.md       | 581 +++++++++++++++---------------------------
 gcc/config/s390/subst.md      | 180 +++++++++++++
 gcc/config/s390/vector.md     | 138 +++++-----
 gcc/gensupport.c              |  41 +--
 6 files changed, 520 insertions(+), 459 deletions(-)
 create mode 100644 gcc/config/s390/subst.md

-- 
1.9.1