Commit Graph

688 Commits

Author SHA1 Message Date
Elena Demikhovsky 5e2f8c4231 AVX-512: Added all forms of VPABS instruction
Added all intrinsics, tests for encoding, tests for intrinsics.

llvm-svn: 240386
2015-06-23 08:19:46 +00:00
Alexander Kornienko 70bc5f1398 Fixed/added namespace ending comments using clang-tidy. NFC
The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!

llvm-svn: 240137
2015-06-19 15:57:42 +00:00
Asaf Badouh 81f03c30a5 [AVX512]
add instructions: VPAVGB and VPAVGW


review
http://reviews.llvm.org/D10504

llvm-svn: 240012
2015-06-18 12:30:53 +00:00
Simon Pilgrim cae7b94cbd [X86][SSE] Vectorize v2i32 to v2f64 conversions
This patch enables support for the conversion of v2i32 to v2f64 to use the CVTDQ2PD xmm instruction and stay on the SSE unit instead of scalarizing, sign extending to i64 and using CVTSI2SDQ scalar conversions.

Differential Revision: http://reviews.llvm.org/D10433

llvm-svn: 239855
2015-06-16 21:40:28 +00:00
Igor Breger abe4a79b75 AVX-512: Implemented cvtsi2ss/d cvtusi2ss/d instructions with round control for KNL.
Added intrinsics for cvtsi2ss/d instructions.
Added tests for intrinsics and encoding.

Differential Revision: http://reviews.llvm.org/D10430

llvm-svn: 239694
2015-06-14 12:44:55 +00:00
Asaf Badouh 402ebb34af re-apply 238809
AVX-512: Implemented GETEXP instruction for KNL and SKX
Added rounding mode modifier for SQRTPS/PD
Added tests for encoding and intrinsics.
CR:
http://reviews.llvm.org/D9991

llvm-svn: 238923
2015-06-03 13:41:48 +00:00
Elena Demikhovsky 9e38086534 AVX-512: Implemented SHUFF32x4/SHUFF64x2/SHUFI32x4/SHUFI64x2 instructions for SKX and KNL.
Added tests for encoding.

By Igor Breger (igor.breger@intel.com)

llvm-svn: 238917
2015-06-03 10:56:40 +00:00
Simon Pilgrim 452252e6c8 [X86] Removed (unused) FSRL x86 operation
This patch removes the old X86ISD::FSRL op - which allowed float vectors to use the byte right shift operations (causing a domain switch....).

Since the refactoring of the shuffle lowering code this no longer has any use.

Differential Revision: http://reviews.llvm.org/D10169

llvm-svn: 238906
2015-06-03 08:32:36 +00:00
Asaf Badouh 8d897dd05f revert 238809
llvm-svn: 238810
2015-06-02 07:45:19 +00:00
Asaf Badouh 17de10f37e AVX-512: Implemented GETEXP instruction for KNL and SKX
Added rounding mode modifier for SQRTPS/PD
Added tests for encoding and intrinsics.

llvm-svn: 238809
2015-06-02 07:18:14 +00:00
Elena Demikhovsky 3582eb3b39 AVX-512: Implemented VRANGEPD and VRANGEPD instructions for SKX.
Implemented DAG lowering for all these forms.
Added tests for encoding.

By Igor Breger (igor.breger@intel.com)

llvm-svn: 238738
2015-06-01 11:05:34 +00:00
Elena Demikhovsky 42c96d9c0a AVX-512: Implemented VFIXUPIMMPD and VFIXUPIMMPS instructions for KNL and SKX
Implemented DAG lowering for all these forms.
Added tests for encoding.

by Igor Breger (igor.breger@intel.com)

llvm-svn: 238728
2015-06-01 06:50:49 +00:00
Matt Arsenault bd7d80a4a6 Add address space argument to isLegalAddressingMode
This is important because of different addressing modes
depending on the address space for GPU targets.

This only adds the argument, and does not update
any of the uses to provide the correct address space.

llvm-svn: 238723
2015-06-01 05:31:59 +00:00
Chandler Carruth 6ba9730a4e [x86] Implement a faster vector population count based on the PSHUFB
in-register LUT technique.

Summary:
A description of this technique can be found here:
http://wm.ite.pl/articles/sse-popcount.html

The core of the idea is to use an in-register lookup table and the
PSHUFB instruction to compute the population count for the low and high
nibbles of each byte, and then to use horizontal sums to aggregate these
into vector population counts with wider element types.

On x86 there is an instruction that will directly compute the horizontal
sum for the low 8 and high 8 bytes, giving vNi64 popcount very easily.
Various tricks are used to get vNi32 and vNi16 from the vNi8 that the
LUT computes.

The base implemantion of this, and most of the work, was done by Bruno
in a follow up to D6531. See Bruno's detailed post there for lots of
timing information about these changes.

I have extended Bruno's patch in the following ways:

0) I committed the new tests with baseline sequences so this shows
   a diff, and regenerated the tests using the update scripts.

1) Bruno had noticed and mentioned in IRC a redundant mask that
   I removed.

2) I introduced a particular optimization for the i32 vector cases where
   we use PSHL + PSADBW to compute the the low i32 popcounts, and PSHUFD
   + PSADBW to compute doubled high i32 popcounts. This takes advantage
   of the fact that to line up the high i32 popcounts we have to shift
   them anyways, and we can shift them by one fewer bit to effectively
   divide the count by two. While the PSHUFD based horizontal add is no
   faster, it doesn't require registers or load traffic the way a mask
   would, and provides more ILP as it happens on different ports with
   high throughput.

3) I did some code cleanups throughout to simplify the implementation
   logic.

4) I refactored it to continue to use the parallel bitmath lowering when
   SSSE3 is not available to preserve the performance of that version on
   SSE2 targets where it is still much better than scalarizing as we'll
   still do a bitmath implementation of popcount even in scalar code
   there.

With #1 and #2 above, I analyzed the result in IACA for sandybridge,
ivybridge, and haswell. In every case I measured, the throughput is the
same or better using the LUT lowering, even v2i64 and v4i64, and even
compared with using the native popcnt instruction! The latency of the
LUT lowering is often higher than the latency of the scalarized popcnt
instruction sequence, but I think those latency measurements are deeply
misleading. Keeping the operation fully in the vector unit and having
many chances for increased throughput seems much more likely to win.

With this, we can lower every integer vector popcount implementation
using the LUT strategy if we have SSSE3 or better (and thus have
PSHUFB). I've updated the operation lowering to reflect this. This also
fixes an issue where we were scalarizing horribly some AVX lowerings.

Finally, there are some remaining cleanups. There is duplication between
the two techniques in how they perform the horizontal sum once the byte
population count is computed. I'm going to factor and merge those two in
a separate follow-up commit.

Differential Revision: http://reviews.llvm.org/D10084

llvm-svn: 238636
2015-05-30 03:20:59 +00:00
Elena Demikhovsky ad9c396838 AVX-512: Added VBROADCASTF64X4, VBROADCASTF64X2, VBROADCASTI32X8, and other instructions from this set
Added encoding tests.

llvm-svn: 237557
2015-05-18 06:42:57 +00:00
Daniel Sanders d049669546 [x86] Distinguish the 'o', 'v', 'X', and 'i' inline assembly memory constraints.
Summary:
But still handle them the same way since I don't know how they differ on
this target.

Of these, 'o' and 'v' are not tested but were already implemented.

I'm not sure why 'i' is required for X86 since it's supposed to be an
immediate constraint rather than a memory constraint. A test asserts
without it so I've included it for now.

No functional change intended.

Reviewers: nadav

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8254

llvm-svn: 237517
2015-05-16 12:09:54 +00:00
Eric Christopher 824f42f209 Migrate existing backends that care about software floating point
to use the information in the module rather than TargetOptions.

We've had and clang has used the use-soft-float attribute for some
time now so have the backends set a subtarget feature based on
a particular function now that subtargets are created based on
functions and function attributes.

For the one middle end soft float check go ahead and create
an overloadable TargetLowering::useSoftFloat function that
just checks the TargetSubtargetInfo in all cases.

Also remove the command line option that hard codes whether or
not soft-float is set by using the attribute for all of the
target specific test cases - for the generic just go ahead and
add the attribute in the one case that showed up.

llvm-svn: 237079
2015-05-12 01:26:05 +00:00
Elena Demikhovsky 0d7e9364d1 AVX-512: Added SKX instructions and intrinsics:
{add/sub/mul/div/} x {ps/pd} x {128/256} 2. max/min with sae

By Asaf Badouh (asaf.badouh@intel.com)

llvm-svn: 236971
2015-05-11 06:05:05 +00:00
Pat Gavlin cc0431d1c0 Extend the statepoint intrinsic to allow statepoints to be marked as transitions from GC-aware code to code that is not GC-aware.
This changes the shape of the statepoint intrinsic from:

  @llvm.experimental.gc.statepoint(anyptr target, i32 # call args, i32 unused, ...call args, i32 # deopt args, ...deopt args, ...gc args)

to:

  @llvm.experimental.gc.statepoint(anyptr target, i32 # call args, i32 flags, ...call args, i32 # transition args, ...transition args, i32 # deopt args, ...deopt args, ...gc args)

This extension offers the backend the opportunity to insert (somewhat) arbitrary code to manage the transition from GC-aware code to code that is not GC-aware and back.

In order to support the injection of transition code, this extension wraps the STATEPOINT ISD node generated by the usual lowering lowering with two additional nodes: GC_TRANSITION_START and GC_TRANSITION_END. The transition arguments that were passed passed to the intrinsic (if any) are lowered and provided as operands to these nodes and may be used by the backend during code generation.

Eventually, the lowering of the GC_TRANSITION_{START,END} nodes should be informed by the GC strategy in use for the function containing the intrinsic call; for now, these nodes are instead replaced with no-ops.

Differential Revision: http://reviews.llvm.org/D9501

llvm-svn: 236888
2015-05-08 18:07:42 +00:00
Matthias Braun d04893fa36 Change getTargetNodeName() to produce compiler warnings for missing cases, fix them
llvm-svn: 236775
2015-05-07 21:33:59 +00:00
Elena Demikhovsky 29792e9a80 AVX-512: Added all forms of FP compare instructions for KNL and SKX.
Added intrinsics for the instructions. CC parameter of the intrinsics was changed from i8 to i32 according to the spec.

By Igor Breger (igor.breger@intel.com)

llvm-svn: 236714
2015-05-07 11:24:42 +00:00
Elena Demikhovsky 60eb9db7bb AVX-512: added calling convention for i1 vectors in 32-bit mode.
Fixed some bugs in extend/truncate for AVX-512 target.
Removed VBROADCASTM (masked broadcast) node, since it is not used any more.

llvm-svn: 236420
2015-05-04 12:40:50 +00:00
Elena Demikhovsky 52266388f8 AVX-512: added integer "add" and "sub" instructions with saturation for SKX
with intrinsics and tests

by Asaf Badouh (asaf.badouh@intel.com)

llvm-svn: 236418
2015-05-04 12:35:55 +00:00
Sanjay Patel 7024b8121a [x86] Implement combineRepeatedFPDivisors
Set the transform bar at 2 divisions because the fastest current
x86 FP divider circuit is in SandyBridge / Haswell at 10 cycle
latency (best case) relative to a 5 cycle multiplier. 
So that's the worst case for this transform (no latency win), 
but multiplies are obviously pipelined while divisions are not,
so there's still a big throughput win which we would expect to
show up in typical FP code.

These are the sequences I'm comparing:

  divss   %xmm2, %xmm0
  mulss   %xmm1, %xmm0
  divss   %xmm2, %xmm0

Becomes:

  movss   LCPI0_0(%rip), %xmm3    ## xmm3 = mem[0],zero,zero,zero
  divss   %xmm2, %xmm3
  mulss   %xmm3, %xmm0
  mulss   %xmm1, %xmm0
  mulss   %xmm3, %xmm0

[Ignore for the moment that we don't optimize the chain of 3 multiplies
into 2 independent fmuls followed by 1 dependent fmul...this is the DAG
version of: https://llvm.org/bugs/show_bug.cgi?id=21768 ...if we fix that,
then the transform becomes even more profitable on all targets.]

Differential Revision: http://reviews.llvm.org/D8941

llvm-svn: 235012
2015-04-15 15:22:55 +00:00
Daniel Sanders bf5b80f5f9 Make each target map all inline assembly memory constraints to InlineAsm::Constraint_m. NFC.
Summary:
This is instead of doing this in target independent code and is the last
non-functional change before targets begin to distinguish between
different memory constraints when selecting code for the ISD::INLINEASM
node.

Next, each target will individually move away from the idea that all
memory constraints behave like 'm'.

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D8173

llvm-svn: 232373
2015-03-16 13:13:41 +00:00
JF Bastien f14889ee34 Mutate TargetLowering::shouldExpandAtomicRMWInIR to specifically dictate how AtomicRMWInsts are expanded.
Summary:
In PNaCl, most atomic instructions have their own @llvm.nacl.atomic.* function, each one, with a few exceptions, represents a consistent behaviour across all NaCl-supported targets. Unfortunately, the atomic RMW operations nand, [u]min, and [u]max aren't directly represented by any such @llvm.nacl.atomic.* function. This patch refines shouldExpandAtomicRMWInIR in TargetLowering so that a future `Le32TargetLowering` class can selectively inform the caller how the target desires the atomic RMW instruction to be expanded (ie via load-linked/store-conditional for ARM/AArch64, via cmpxchg for X86/others?, or not at all for Mips) if at all.

This does not represent a behavioural change and as such no tests were added.

Patch by: Richard Diamond.

Reviewers: jfb

Reviewed By: jfb

Subscribers: jfb, aemerson, t.p.northover, llvm-commits

Differential Revision: http://reviews.llvm.org/D7713

llvm-svn: 231250
2015-03-04 15:47:57 +00:00
Sanjay Patel 36a2dc895f remove enum value names from comments; NFC
llvm-svn: 231129
2015-03-03 20:58:35 +00:00
Eric Christopher 11e4df73c8 getRegForInlineAsmConstraint wants to use TargetRegisterInfo for
a lookup, pass that in rather than use a naked call to getSubtargetImpl.
This involved passing down and around either a TargetMachine or
TargetRegisterInfo. Update all callers/definitions around the targets
and SelectionDAG.

llvm-svn: 230699
2015-02-26 22:38:43 +00:00
Eric Christopher 23a3a7c871 Remove an argument-less call to getSubtargetImpl from TargetLoweringBase.
This required plumbing a TargetRegisterInfo through computeRegisterProperties
and into findRepresentativeClass which uses it for register class
iteration. This required passing a subtarget into a few target specific
initializations of TargetLowering.

llvm-svn: 230583
2015-02-26 00:00:24 +00:00
Elena Demikhovsky 52e81bc499 AVX-512: recommitted 229837 + bugfix + test
llvm-svn: 230223
2015-02-23 15:12:31 +00:00
Benjamin Kramer cd8e4ebadb Remove dead prototype.
llvm-svn: 230137
2015-02-21 14:35:00 +00:00
Eric Christopher 0d94fa98e5 Revert "AVX-512: Full implementation for VRNDSCALESS/SD instructions and intrinsics."
The instructions were being generated on architectures that don't support avx512.

This reverts commit r229837.

llvm-svn: 229942
2015-02-20 00:45:28 +00:00
Elena Demikhovsky 69e8b45b13 AVX-512: Full implementation for VRNDSCALESS/SD instructions and intrinsics.
llvm-svn: 229837
2015-02-19 10:48:04 +00:00
Elena Demikhovsky 714f23bcdb AVX-512: Added support for FP instructions with embedded rounding mode.
By Asaf Badouh <asaf.badouh@intel.com>

llvm-svn: 229645
2015-02-18 07:59:20 +00:00
Ahmed Bougacha e892d13d90 [CodeGen] Add hook/combine to form vector extloads, enabled on X86.
The combine that forms extloads used to be disabled on vector types,
because "None of the supported targets knows how to perform load and
sign extend on vectors in one instruction."

That's not entirely true, since at least SSE4.1 X86 knows how to do
those sextloads/zextloads (with PMOVS/ZX).
But there are several aspects to getting this right.
First, vector extloads are controlled by a profitability callback.
For instance, on ARM, several instructions have folded extload forms,
so it's not always beneficial to create an extload node (and trying to
match extloads is a whole 'nother can of worms).

The interesting optimization enables folding of s/zextloads to illegal
(splittable) vector types, expanding them into smaller legal extloads.

It's not ideal (it introduces some legalization-like behavior in the
combine) but it's better than the obvious alternative: form illegal
extloads, and later try to split them up.  If you do that, you might
generate extloads that can't be split up, but have a valid ext+load
expansion.  At vector-op legalization time, it's too late to generate
this kind of code, so you end up forced to scalarize. It's better to
just avoid creating egregiously illegal nodes.

This optimization is enabled unconditionally on X86.

Note that the splitting combine is happy with "custom" extloads. As
is, this bypasses the actual custom lowering, and just unrolls the
extload. But from what I've seen, this is still much better than the
current custom lowering, which does some kind of unrolling at the end
anyway (see for instance load_sext_4i8_to_4i64 on SSE2, and the added
FIXME).

Also note that the existing combine that forms extloads is now also
enabled on legal vectors.  This doesn't have a big effect on X86
(because sext+load is usually combined to sext_inreg+aextload).
On ARM it fires on some rare occasions; that's for a separate commit.

Differential Revision: http://reviews.llvm.org/D6904

llvm-svn: 228325
2015-02-05 18:31:02 +00:00
Bruno Cardoso Lopes ab9ae87623 [X86][MMX] Handle i32->mmx conversion using movd
Implement a BITCAST dag combine to transform i32->mmx conversion patterns
into a X86 specific node (MMX_MOVW2D) and guarantee that moves between
i32 and x86mmx are better handled, i.e., don't use store-load to do the
conversion..

llvm-svn: 228293
2015-02-05 13:23:07 +00:00
Eric Christopher 05b819718c Reuse a bunch of cached subtargets and remove getSubtarget calls
without a Function argument.

llvm-svn: 227814
2015-02-02 17:38:43 +00:00
Eric Christopher 295596a0a7 Remove the last vestiges of resetOperationActions.
llvm-svn: 227648
2015-01-31 00:21:17 +00:00
Elena Demikhovsky 7b0dd39db6 AVX-512: Added FMA intrinsics with rounding mode
By Asaf Badouh and Elena Demikhovsky

Added special nodes for rounding: FMADD_RND, FMSUB_RND..
It will prevent merge between nodes with rounding and other standard nodes.

llvm-svn: 227303
2015-01-28 10:21:27 +00:00
David Majnemer 29c52f7449 X86: Don't make illegal GOTTPOFF relocations
"ELF Handling for Thread-Local Storage" specifies that R_X86_64_GOTTPOFF
relocation target a movq or addq instruction.

Prohibit the truncation of such loads to movl or addl.

This fixes PR22083.

Differential Revision: http://reviews.llvm.org/D6839

llvm-svn: 225250
2015-01-06 07:12:52 +00:00
Andrea Di Biagio 22ee3f63b9 [CodeGenPrepare] Teach when it is profitable to speculate calls to @llvm.cttz/ctlz.
If the control flow is modelling an if-statement where the only instruction in
the 'then' basic block (excluding the terminator) is a call to cttz/ctlz,
CodeGenPrepare can try to speculate the cttz/ctlz call and simplify the control
flow graph.

Example:
\code
entry:
  %cmp = icmp eq i64 %val, 0
  br i1 %cmp, label %end.bb, label %then.bb

then.bb:
  %c = tail call i64 @llvm.cttz.i64(i64 %val, i1 true)
  br label %end.bb

end.bb:
  %cond = phi i64 [ %c, %then.bb ], [ 64, %entry]
\code

In this example, basic block %then.bb is taken if value %val is not zero.
Also, the phi node in %end.bb would propagate the size-of in bits of %val
only if %val is equal to zero.

With this patch, CodeGenPrepare will try to hoist the call to cttz from %then.bb
into basic block %entry only if cttz is cheap to speculate for the target.

Added two new hooks in TargetLowering.h to let targets customize the behavior
(i.e. decide whether it is cheap or not to speculate calls to cttz/ctlz). The
two new methods are 'isCheapToSpeculateCtlz' and 'isCheapToSpeculateCttz'.
By default, both methods return 'false'.
On X86, method 'isCheapToSpeculateCtlz' returns true only if the target has
LZCNT. Method 'isCheapToSpeculateCttz' only returns true if the target has BMI.

Differential Revision: http://reviews.llvm.org/D6728

llvm-svn: 224899
2014-12-28 11:07:35 +00:00
Michael Kuperstein 047b1a0400 [DAGCombine] Slightly improve lowering of BUILD_VECTOR into a shuffle.
This handles the case of a BUILD_VECTOR being constructed out of elements extracted from a vector twice the size of the result vector. Previously this was always scalarized. Now, we try to construct a shuffle node that feeds on extract_subvectors.

This fixes PR15872 and provides a partial fix for PR21711.

Differential Revision: http://reviews.llvm.org/D6678

llvm-svn: 224429
2014-12-17 12:32:17 +00:00
Elena Demikhovsky 908dbf48c8 AVX-512: Added all forms of COMPRESS instruction
+ intrinsics + tests

llvm-svn: 224019
2014-12-11 15:02:24 +00:00
Elena Demikhovsky be8808dc3f AVX-512: Intrinsics for ERI
3 instructions: vrcp28, vrsqrt28, vexp2, only vector forms.
Intrinsics include SAE (Suppres All Exceptions) parameter.

http://reviews.llvm.org/D6214

llvm-svn: 221774
2014-11-12 07:31:03 +00:00
Sanjay Patel e2e589288f Use rcpss/rcpps (X86) to speed up reciprocal calcs (PR21385).
This is a first step for generating SSE rcp instructions for reciprocal
calcs when fast-math allows it. This is very similar to the rsqrt optimization
enabled in D5658 ( http://reviews.llvm.org/rL220570 ).

For now, be conservative and only enable this for AMD btver2 where performance
improves significantly both in terms of latency and throughput.

We may never enable this codegen for Intel Core* chips because the divider circuits
are just too fast. On SandyBridge, divss can be as fast as 10 cycles versus the 21
cycle critical path for the rcp + mul + sub + mul + add estimate.

Follow-on patches may allow configuration of the number of Newton-Raphson refinement
steps, add AVX512 support, and enable the optimization for more chips.

More background here: http://llvm.org/bugs/show_bug.cgi?id=21385

Differential Revision: http://reviews.llvm.org/D6175

llvm-svn: 221706
2014-11-11 20:51:00 +00:00
Quentin Colombet dbe33e7aa4 [X86] Lower VSELECT into SHRUNKBLEND when we shrink the bits used into the
condition to match a blend.
This prevents optimizations that work on VSELECT to perform invalid
transformations. Indeed, the optimized condition does not match the vector
boolean content that is expected and bad things may happen.

This patch yields the exact same code on the whole test-suite + specs (-O3 and
-O3 -march=core-avx2), it improves one test case (vector-blend.ll) and fixes a
bug reduced in vselect-avx.ll.

<rdar://problem/18819506>

llvm-svn: 221429
2014-11-06 02:25:03 +00:00
Ahmed Bougacha 12eb558bd9 [X86] 8bit divrem: Improve codegen for AH register extraction.
For 8-bit divrems where the remainder is used, we used to generate:
    divb  %sil
    shrw  $8, %ax
    movzbl  %al, %eax

That was to avoid an H-reg access, which is problematic mainly because
it isn't possible in REX-prefixed instructions.

This patch optimizes that to:
    divb  %sil
    movzbl  %ah, %eax

To do that, we explicitly extend AH, and extract the L-subreg in the
resulting register.  The extension is done using the NOREX variants of
MOVZX.  To support signed operations, MOVSX_NOREX is also added.
Further, this introduces a new SDNode type, [us]divrem_ext_hreg, which is
then lowered to a sequence containing a single zext (rather than 2).

Differential Revision: http://reviews.llvm.org/D6064

llvm-svn: 221176
2014-11-03 20:26:35 +00:00
Sanjay Patel 957efc23bb Use rsqrt (X86) to speed up reciprocal square root calcs
This is a first step for generating SSE rsqrt instructions for
reciprocal square root calcs when fast-math is allowed.

For now, be conservative and only enable this for AMD btver2
where performance improves significantly - for example, 29%
on llvm/projects/test-suite/SingleSource/Benchmarks/BenchmarkGame/n-body.c
(if we convert the data type to single-precision float).

This patch adds a two constant version of the Newton-Raphson
refinement algorithm to DAGCombiner that can be selected by any target
via a parameter returned by getRsqrtEstimate()..

See PR20900 for more details:
http://llvm.org/bugs/show_bug.cgi?id=20900

Differential Revision: http://reviews.llvm.org/D5658

llvm-svn: 220570
2014-10-24 17:02:16 +00:00
Ahmed Bougacha 5175bcf43a [X86] Improve mul w/ overflow codegen, to MUL8+SETO.
Currently, @llvm.smul.with.overflow.i8 expands to 9 instructions, where
3 are really needed.

This adds X86ISD::UMUL8/SMUL8 SD nodes, and custom lowers them to
MUL8/IMUL8 + SETO.

i8 is a special case because there is no two/three operand variants of
(I)MUL8, so the first operand and return value need to go in AL/AX.

Also, we can't write patterns for these instructions: TableGen refuses
patterns where output operands don't match SDNode results. In this case,
instructions where the output operand is an implicitly defined register.

A related special case (and FIXME) exists for MUL8 (X86InstrArith.td):

  // FIXME: Used for 8-bit mul, ignore result upper 8 bits.
  // This probably ought to be moved to a def : Pat<> if the
  // syntax can be accepted.
  [(set AL, (mul AL, GR8:$src)), (implicit EFLAGS)]

Ideally, these go away with UMUL8, but we still need to improve TableGen
support of implicit operands in patterns.

Before this change:
  movsbl  %sil, %eax
  movsbl  %dil, %ecx
  imull   %eax, %ecx
  movb    %cl, %al
  sarb    $7, %al
  movzbl  %al, %eax
  movzbl  %ch, %esi
  cmpl    %eax, %esi
  setne   %al

After:
  movb    %dil, %al
  imulb   %sil
  seto    %al

Also, remove a made-redundant testcase for PR19858, and enable more FastISel
ALU-overflow tests for SelectionDAG too.

Differential Revision: http://reviews.llvm.org/D5809

llvm-svn: 220516
2014-10-23 21:55:31 +00:00
Eric Christopher 12f4a78581 constify TargetMachine parameter for X86TargetLowering.
llvm-svn: 218804
2014-10-01 20:38:22 +00:00