Commit Graph

529 Commits

Author SHA1 Message Date
Richard Sandiford 113c870397 [SystemZ] Add support for TMHH, TMHL, TMLH and TMLL
For now this just handles simple comparisons of an ANDed value with zero.
The CC value provides enough information to do any comparison for a
2-bit mask, and some nonzero comparisons with more populated masks,
but that's all future work.

llvm-svn: 189819
2013-09-03 15:38:35 +00:00
Richard Sandiford 35b9be298a [SystemZ] Add support for TMHH, TMHL, TMLH and TMLL
For now just handles simple comparisons of an ANDed value with zero.
The CC value provides enough information to do any comparison for a
2-bit mask, and some nonzero comparisons with more populated masks,
but that's all future work.

llvm-svn: 189469
2013-08-28 10:31:43 +00:00
Richard Sandiford be133a8757 [SystemZ] Extend memcmp support to all constant lengths
This uses the infrastructure added for memcpy and memmove in r189331.

llvm-svn: 189458
2013-08-28 09:01:51 +00:00
Richard Sandiford 5e318f0bfe [SystemZ] Extend memcpy and memset support to all constant lengths
Lengths up to a certain threshold (currently 6 * 256) use a series of MVCs.
Lengths above that threshold use a loop to handle X*256 bytes followed
by a single MVC to handle the excess (if any).  This loop will also be
needed in future when support for variable lengths is added.

Because the same tablegen classes are used to define MVC and CLC,
the patch also has the side-effect of defining a pseudo loop instruction
for CLC.  That instruction isn't used yet (and wouldn't be handled correctly
if it were).  I'm planning to use it soon though.

llvm-svn: 189331
2013-08-27 09:54:29 +00:00
Richard Sandiford 03481334b5 [SystemZ] Add basic prefetch support
Just the instructions and intrinsics for now.

llvm-svn: 189100
2013-08-23 11:36:42 +00:00
Richard Sandiford 24e597b8c5 [SystemZ] Try reversing comparisons whose first operand is in memory
This allows us to make more use of the many compare reg,mem instructions.

llvm-svn: 189099
2013-08-23 11:27:19 +00:00
Richard Sandiford a481f58542 [SystemZ] Prefer LHI;ST... over LAY;MV...
If we had a store of an integer to memory, and the integer and store size
were suitable for a form of MV..., we used MV... no matter what.  We could
then have sequences like:

    lay %r2, 0(%r3,%r4)
    mvi 0(%r2), 4

In these cases it seems better to force the constant into a register
and use a normal store:

    lhi %r2, 4
    stc %r2, 0(%r3, %r4)

since %r2 is more likely to be hoisted and is easier to rematerialize.

llvm-svn: 189098
2013-08-23 11:18:53 +00:00
Richard Sandiford 37cd6cfba2 Turn MipsOptimizeMathLibCalls into a target-independent scalar transform
...so that it can be used for z too.  Most of the code is the same.
The only real change is to use TargetTransformInfo to test when a sqrt
instruction is available.

The pass is opt-in because at the moment it only handles sqrt.

llvm-svn: 189097
2013-08-23 10:27:02 +00:00
Richard Sandiford 7d86e47d04 [SystemZ] Define remainig *MUL_LOHI patterns
The initial port used MLG(R) for i64 UMUL_LOHI but left the other three
combinations as not-legal-or-custom.  Although 32x32->{32,32}
multiplications exist, they're not as quick as doing a normal 64-bit
multiplication, so it didn't seem like i32 SMUL_LOHI and UMUL_LOHI
would be useful.  There's also no direct instruction for i64 SMUL_LOHI,
so it needs to be implemented in terms of UMUL_LOHI.

However, not defining these patterns means that we don't convert
division by a constant into multiplication, so this patch fills
in the other cases.  The new i64 SMUL_LOHI sequence is simpler
than the one that we used previously for 64x64->128 multiplication,
so int-mul-08.ll now tests the full sequence.

llvm-svn: 188898
2013-08-21 09:34:56 +00:00
Richard Sandiford af5f66ac9e [SystemZ] Use FI[EDX]BRA for codegen
llvm-svn: 188895
2013-08-21 09:04:20 +00:00
Richard Sandiford 8e92c389e4 [SystemZ] Add FI[EDX]BRA
These are extensions of the existing FI[EDX]BR instructions, but use a spare
bit to suppress inexact conditions.

llvm-svn: 188894
2013-08-21 08:58:08 +00:00
Richard Sandiford 2bf7b8cc4e [SystemZ] Update README
We now use MVST, CLST and SRST for the obvious cases.

llvm-svn: 188781
2013-08-20 09:40:35 +00:00
Richard Sandiford 6f6d55161b [SystemZ] Use SRST to optimize memchr
SystemZTargetLowering::emitStringWrapper() previously loaded the character
into R0 before the loop and made R0 live on entry.  I'd forgotten that
allocatable registers weren't allowed to be live across blocks at this stage,
and it confused LiveVariables enough to cause a miscompilation of f3 in
memchr-02.ll.

This patch instead loads R0 in the loop and leaves LICM to hoist it
after RA.  This is actually what I'd tried originally, but I went for
the manual optimisation after noticing that R0 often wasn't being hoisted.
This bug forced me to go back and look at why, now fixed as r188774.

We should also try to optimize null checks so that they test the CC result
of the SRST directly.  The select between null and the SRST GPR result could
then usually be deleted as dead.

llvm-svn: 188779
2013-08-20 09:38:48 +00:00
Richard Sandiford 784a580312 [SystemZ] Add negative integer absolute (load negative)
For now this matches the equivalent of (neg (abs ...)), which did hit a few
times in projects/test-suite.  We should probably also match cases where
absolute-like selects are used with reversed arguments.

llvm-svn: 188671
2013-08-19 12:56:58 +00:00
Richard Sandiford 4b89705490 [SystemZ] Add integer absolute (load positive)
llvm-svn: 188670
2013-08-19 12:48:54 +00:00
Richard Sandiford 709bda66b9 [SystemZ] Add support for sibling calls
This first cut is pretty conservative.  The final argument register (R6)
is call-saved, so we would need to make sure that the R6 argument to a
sibling call is the same as the R6 argument to the calling function,
which seems worth keeping as a separate patch.

Saying that integer truncations are free means that we no longer
use the extending instructions LGF and LLGF for spills in int-conv-09.ll
and int-conv-10.ll.  Instead we treat the registers as 64 bits wide and
truncate them to 32-bits where necessary.  I think it's unlikely we'd
use LGF and LLGF for spills in other situations for the same reason,
so I'm removing the tests rather than replacing them.  The associated
code is generic and applies to many more instructions than just
LGF and LLGF, so there is no corresponding code removal.

llvm-svn: 188669
2013-08-19 12:42:31 +00:00
Richard Sandiford 0dec06a28c [SystemZ] Use SRST to implement strlen and strnlen
It would also make sense to use it for memchr; I'm working on that now.

llvm-svn: 188547
2013-08-16 11:41:43 +00:00
Richard Sandiford bb83a50f57 [SystemZ] Use MVST to implement strcpy and stpcpy
llvm-svn: 188546
2013-08-16 11:29:37 +00:00
Richard Sandiford ca23271010 [SystemZ] Use CLST to implement strcmp
llvm-svn: 188544
2013-08-16 11:21:54 +00:00
Richard Sandiford e3827751e2 [SystemZ] Fix handling of 64-bit memcmp results
Generalize r188163 to cope with return types other than MVT::i32, just
as the existing visitMemCmpCall code did.  I've split this out into a
subroutine so that it can be used for other upcoming patches.

I also noticed that I'd used the wrong API to record the out chain.
It's a load that uses DAG.getRoot() rather than getRoot(), so the out
chain should go on PendingLoads.  I don't have a testcase for that because
we don't do any interesting scheduling on z yet.

llvm-svn: 188540
2013-08-16 10:55:47 +00:00
Richard Sandiford a59012577c [SystemZ] Fix sign of integer memcmp result
r188163 used CLC to implement memcmp.  Code that compares the result
directly against zero can test the CC value produced by CLC, but code
that needs an integer result must use IPM.  The sequence I'd used was:

   ipm <reg>
   sll <reg>, 2
   sra <reg>, 30

but I'd forgotten that this inverts the order, so that CC==1 ("less")
becomes an integer greater than zero, and CC==2 ("greater") becomes
an integer less than zero.  This sequence should only be used if the
CLC arguments are reversed to compensate.  The problem then is that
the branch condition must also be reversed when testing the CLC
result directly.

Rather than do that, I went for a different sequence that works with
the natural CLC order:

   ipm <reg>
   srl <reg>, 28
   rll <reg>, <reg>, 31

One advantage of this is that it doesn't clobber CC.  A disadvantage
is that any sign extension to 64 bits must be done separately,
rather than being folded into the shifts.

llvm-svn: 188538
2013-08-16 10:22:54 +00:00
Richard Sandiford 564681c88d [SystemZ] Use CLC and IPM to implement memcmp
For now this is restricted to fixed-length comparisons with a length
in the range [1, 256], as for memcpy() and MVC.

llvm-svn: 188163
2013-08-12 10:28:10 +00:00
Richard Sandiford 761703a248 [SystemZ] Add a definition of the CLC instruction
llvm-svn: 188162
2013-08-12 10:17:33 +00:00
Richard Sandiford 87326c73c6 [SystemZ] Add a definition of the IPM instruction
llvm-svn: 188161
2013-08-12 10:05:58 +00:00
Richard Sandiford 9140910be8 [SystemZ] Update README
llvm-svn: 188062
2013-08-09 09:25:57 +00:00
Richard Sandiford 0897fce2f4 [SystemZ] Optimize floating-point comparisons with zero
This follows the same lines as the integer code.  In the end it seemed
easier to have a second 4-bit mask in TSFlags to specify the compare-like
CC values.  That eats one more TSFlags bit than adding a CCHasUnordered
would have done, but it feels more concise.

llvm-svn: 187883
2013-08-07 11:10:06 +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
NAKAMURA Takumi aaf66c7357 Target/*/CMakeLists.txt: Add the dependency to CommonTableGen explicitly for each corresponding CodeGen.
Without explicit dependencies, both per-file action and in-CommonTableGen action could run in parallel.
It races to emit *.inc files simultaneously.

llvm-svn: 187780
2013-08-06 06:38:37 +00:00
Richard Sandiford c212125d27 [SystemZ] Use BRCT and BRCTG to eliminate add-&-compare sequences
This patch just uses a peephole test for "add; compare; branch" sequences
within a single block.  The IR optimizers already convert loops to
decrement-and-branch-on-nonzero form in some cases, so even this
simplistic test triggers many times during a clang bootstrap and
projects/test-suite run.  It looks like there are still cases where we
need to more strongly prefer branches on nonzero though.  E.g. I saw a
case where a loop that started out with a check for 0 ended up with a
check for -1.  I'll try to look at that sometime.

I ended up adding the Reference class because MachineInstr::readsRegister()
doesn't check for subregisters (by design, as far as I could tell).

llvm-svn: 187723
2013-08-05 11:23:46 +00:00
Richard Sandiford 9795d8e611 [SystemZ] Add definitions for BRCT and BRCTG
llvm-svn: 187721
2013-08-05 11:07:38 +00:00
Richard Sandiford b49a3ab262 [SystemZ] Use LOAD AND TEST to eliminate comparisons against zero
llvm-svn: 187720
2013-08-05 11:03:20 +00:00
Richard Sandiford c62c64a038 [SystemZ] Add LOAD AND TEST instructions
Just the definitions and MC support.  The next patch uses them for codegen.

llvm-svn: 187719
2013-08-05 11:00:53 +00:00
Richard Sandiford bdbb8af7e6 [SystemZ] Split out comparison elimination into a separate pass
Perhaps predictably, doing comparison elimination on the fly during
SystemZLongBranch turned out to be a bad idea.  The next patches make
use of LOAD AND TEST and BRANCH ON COUNT, both of which require
changes to earlier instructions.

No functionality change intended.

llvm-svn: 187718
2013-08-05 10:58:53 +00:00
Richard Sandiford fd7f4ae6d4 [SystemZ] Reuse CC results for integer comparisons with zero
This also fixes a bug in the predication of LR to LOCR: I'd forgotten
that with these in-place instruction builds, the implicit operands need
to be added manually.  I think this was latent until now, but is tested
by int-cmp-45.c.  It also adds a CC valid mask to STOC, again tested by
int-cmp-45.c.

llvm-svn: 187573
2013-08-01 10:39:40 +00:00
Richard Sandiford a075708abe [SystemZ] Prefer comparisons with zero
Convert >= 1 to > 0, etc.  Using comparison with zero isn't a win on its own,
but it exposes more opportunities for CC reuse (the next patch).

llvm-svn: 187571
2013-08-01 10:29:45 +00:00
Richard Sandiford 791bea4182 [SystemZ] Implement isLegalAddressingMode()
The loop optimizers were assuming that scales > 1 were OK.  I think this
is actually a bug in TargetLoweringBase::isLegalAddressingMode(),
since it seems to be trying to reject anything that isn't r+i or r+r,
but it has no default case for scales other than 0, 1 or 2.  Implementing
the hook for z means that z can no longer test any change there though.

llvm-svn: 187497
2013-07-31 12:58:26 +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 8a757bba10 [SystemZ] Move compare-and-branch generation even later
r187116 moved compare-and-branch generation from the instruction-selection
pass to the peephole optimizer (via optimizeCompare).  It turns out that even
this is a bit too early.  Fused compare-and-branch instructions don't
interact well with predication, where a CC result is needed.  They also
make it harder to reuse the CC side-effects of earlier instructions
(not yet implemented, but the subject of a later patch).

Another problem was that the AnalyzeBranch family of routines weren't
handling compares and branches, so we weren't able to reverse the fused
form in cases where we would reverse a separate branch.  This could have
been fixed by extending AnalyzeBranch, but given the other problems,
I've instead moved the fusing to the long-branch pass, which is also
responsible for the opposite transformation: splitting out-of-range
compares and branches into separate compares and long branches.

I've added a test for the AnalyzeBranch problem.  A test for the
predication problem is included in the next patch, which fixes a bug
in the choice of CC mask.

llvm-svn: 187494
2013-07-31 12:11:07 +00:00
Richard Sandiford 6a06ba36ba [SystemZ] Postpone NI->RISBG conversion to convertToThreeAddress()
r186399 aggressively used the RISBG instruction for immediate ANDs,
both because it can handle some values that AND IMMEDIATE can't,
and because it allows the destination register to be different from
the source.  I realized later while implementing the distinct-ops
support that it would be better to leave the choice up to
convertToThreeAddress() instead.  The AND IMMEDIATE form is shorter
and is less likely to be cracked.

This is a problem for 32-bit ANDs because we assume that all 32-bit
operations will leave the high word untouched, whereas RISBG used in
this way will either clear the high word or copy it from the source
register.  The patch uses the z196 instruction RISBLG for this instead.

This means that z10 will be restricted to NILL, NILH and NILF for
32-bit ANDs, but I think that should be OK for now.  Although we're
using z10 as the base architecture, the optimization work is going
to be focused more on z196 and zEC12.

llvm-svn: 187492
2013-07-31 11:36:35 +00:00
Richard Sandiford 6cf80b3ec0 [SystemZ] Add RISBLG and RISBHG instruction definitions
The next patch will make use of RISBLG for codegen.

llvm-svn: 187490
2013-07-31 11:17:35 +00:00
Richard Sandiford c3f85d73ab [SystemZ] Rework compare and branch support
Before the patch we took advantage of the fact that the compare and
branch are glued together in the selection DAG and fused them together
(where possible) while emitting them.  This seemed to work well in practice.
However, fusing the compare so early makes it harder to remove redundant
compares in cases where CC already has a suitable value.  This patch
therefore uses the peephole analyzeCompare/optimizeCompareInstr pair of
functions instead.

No behavioral change intended, but it paves the way for a later patch.

llvm-svn: 187116
2013-07-25 09:34:38 +00:00
Richard Sandiford f2404164ba [SystemZ] Add LOCR and LOCGR
llvm-svn: 187113
2013-07-25 09:11:15 +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 a68e6f5660 [SystemZ] Add STOC and STOCG
These instructions are allowed to trap even if the condition is false,
so for now they are only used for "*ptr = (cond ? x : *ptr)"-style
constructs.

llvm-svn: 187111
2013-07-25 08:57:02 +00:00
Craig Topper 690d8ea181 Split generated asm mnemonic matching table into a separate table for each asm variant.
This removes the need to store the asm variant in each row of the single table that existed before. Shaves ~16K off the size of X86AsmParser.o.

llvm-svn: 187026
2013-07-24 07:33:14 +00:00
Richard Sandiford fac8b10a84 [SystemZ] Add ALRK, AGLRK, SLRK and SGLRK
Follows the same lines as r186686, but much more limited, since we only
use ADD LOGICAL for multi-i64 additions.

llvm-svn: 186689
2013-07-19 16:37:00 +00:00
Richard Sandiford 7d6a453623 [SystemZ] Add AHIK and AGHIK
I did these as a separate patch because it uses a slightly different
form of RIE layout.

llvm-svn: 186687
2013-07-19 16:32:12 +00:00
Richard Sandiford c575df6dcc [SystemZ] Add ARK, AGRK, SRK and SGRK
The testsuite changes follow the same lines as for r186683.

llvm-svn: 186686
2013-07-19 16:26:39 +00:00
Richard Sandiford c57e586792 [SystemZ] Add NGRK, OGRK and XGRK
Like r186683, but for 64 bits.

llvm-svn: 186685
2013-07-19 16:24:22 +00:00