Commit Graph

15 Commits

Author SHA1 Message Date
Richard Sandiford 198ddf83c1 [SystemZ] Use LOAD AND TEST for comparisons with -0
...since it os equivalent to comparison with +0.

llvm-svn: 196580
2013-12-06 09:59:12 +00:00
Richard Sandiford f03789ca3f [SystemZ] Fix TMHH and TMHL usage for z10 with -O0
I've no idea why I decided to handle TMxx differently from all the other
high/low logic operations, but it was a stupid thing to do.  The high
registers aren't available as separate 32-bit registers on z10,
so subreg_h32 can't be used on a GR64 there.

I've normally been testing with z196 and with -O3 and so hadn't noticed
this until now.

llvm-svn: 195473
2013-11-22 17:28:28 +00:00
Richard Sandiford 2cac763544 [SystemZ] Extend test-under-mask support to high GR32s
llvm-svn: 191773
2013-10-01 14:41:52 +00:00
Richard Sandiford 87a4436456 [SystemZ] Rename subregs and add subreg_h32
Use subreg_hNN and subreg_lNN for the high and low NN bits of a register.
List the low registers first, so that subreg_l32 also means the low 32
bits of a 128-bit register.

Floats are stored in the upper 32 bits of a 64-bit register, so they
should use subreg_h32 rather than subreg_l32.

No behavioral change intended.

llvm-svn: 191659
2013-09-30 10:28:35 +00:00
Richard Sandiford 652784e29a [SystemZ] Define the GR64 low-word logic instructions as pseudo aliases.
Another patch to avoid duplication of encoding information.  Things like
NILF, NILL and NILH are used as both 32-bit and 64-bit instructions.
Here the 64-bit versions are defined as aliases of the 32-bit ones.

llvm-svn: 191369
2013-09-25 11:11:53 +00:00
Richard Sandiford 6cbd7f0c5d [SystemZ] Use subregs for 64-bit truncating stores
Another patch to reduce the duplication of encoding information.
Rather than define separate patterns for truncating 64-bit stores,
use the 32-bit stores with a subreg.  No behavioral changed intended.

llvm-svn: 191365
2013-09-25 10:29:47 +00:00
Richard Sandiford 5bc670bb55 [SystemZ] Tweak integer comparison code
The architecture has many comparison instructions, including some that
extend one of the operands.  The signed comparison instructions use sign
extensions and the unsigned comparison instructions use zero extensions.
In cases where we had a free choice between signed or unsigned comparisons,
we were trying to decide at lowering time which would best fit the available
instructions, taking things like extension type into account.  The code
to do that was getting increasingly hairy and was also making some bad
decisions.  E.g. when comparing the result of two LLCs, it is better to use
CR rather than CLR, since CR can be fused with a branch while CLR can't.

This patch removes the lowering code and instead adds an operand to
integer comparisons to say whether signed comparison is required,
whether unsigned comparison is required, or whether either is OK.
We can then leave the choice of instruction up to the normal isel code.

llvm-svn: 190138
2013-09-06 11:51:39 +00:00
Richard Sandiford 178273a174 [SystemZ] Add NC, OC and XC
For now these are just used to handle scalar ANDs, ORs and XORs in which
all operands are memory.

llvm-svn: 190041
2013-09-05 10:36:45 +00:00
Richard Sandiford 9f11bc1956 [SystemZ] Add floating-point load-and-test instructions
These instructions can also be used as comparisons with zero.

llvm-svn: 187882
2013-08-07 11:03:34 +00:00
Richard Sandiford ee8343822e [SystemZ] Be more careful about inverting CC masks (conditional loads)
Extend r187495 to conditional loads.  I split this out because the
easiest way seemed to be to force a particular operand order in
SystemZISelDAGToDAG.cpp.

llvm-svn: 187496
2013-07-31 12:38:08 +00:00
Richard Sandiford 3d768e334b [SystemZ] Be more careful about inverting CC masks
System z branches have a mask to select which of the 4 CC values should
cause the branch to be taken.  We can invert a branch by inverting the mask.
However, not all instructions can produce all 4 CC values, so inverting
the branch like this can lead to some oddities.  For example, integer
comparisons only produce a CC of 0 (equal), 1 (less) or 2 (greater).
If an integer EQ is reversed to NE before instruction selection,
the branch will test for 1 or 2.  If instead the branch is reversed
after instruction selection (by inverting the mask), it will test for
1, 2 or 3.  Both are correct, but the second isn't really canonical.
This patch therefore keeps track of which CC values are possible
and uses this when inverting a mask.

Although this is mostly cosmestic, it fixes undefined behavior
for the CIJNLH in branch-08.ll.  Another fix would have been
to mask out bit 0 when generating the fused compare and branch,
but the point of this patch is that we shouldn't need to do that
in the first place.

The patch also makes it easier to reuse CC results from other instructions.

llvm-svn: 187495
2013-07-31 12:30:20 +00:00
Richard Sandiford 09a8cf3604 [SystemZ] Add LOC and LOCG
As with the stores, these instructions can trap when the condition is false,
so they are only used for things like (cond ? x : *ptr).

llvm-svn: 187112
2013-07-25 09:04:52 +00:00
Richard Sandiford 9784649157 [SystemZ] Use MVC for simple load/store pairs
Look for patterns of the form (store (load ...), ...) in which the two
locations are known not to partially overlap.  (Identical locations are OK.)
These sequences are better implemented by MVC unless either the load or
the store could use RELATIVE LONG instructions.

The testcase showed that we weren't using LHRL and LGHRL for extload16,
only sextloadi16.  The patch fixes that too.

llvm-svn: 185919
2013-07-09 09:46:39 +00:00
Richard Sandiford b86a83488e [SystemZ] Add conditional store patterns
Add pseudo conditional store instructions, so that we use:

    branch foo:
    store
foo:

instead of:

    load
    branch foo:
    move
foo:
    store

z196 has real 32-bit and 64-bit conditional stores, but we don't use
any z196 instructions yet.

llvm-svn: 185065
2013-06-27 09:27:40 +00:00
Ulrich Weigand 5f613dfd1f [SystemZ] Add back end
This adds the actual lib/Target/SystemZ target files necessary to
implement the SystemZ target.  Note that at this point, the target
cannot yet be built since the configure bits are missing.  Those
will be provided shortly by a follow-on patch.

This version of the patch incorporates feedback from reviews by
Chris Lattner and Anton Korobeynikov.  Thanks to all reviewers!

Patch by Richard Sandiford.

llvm-svn: 181203
2013-05-06 16:15:19 +00:00