Commit Graph

13962 Commits

Author SHA1 Message Date
Artyom Skrobov 7fd67e25aa Adding support for TargetLoweringBase::LibCall
Summary:
TargetLoweringBase::Expand is defined as "Try to expand this to other ops,
otherwise use a libcall." For ISD::UDIV and ISD::SDIV, the choice between
the two possibilities was defined in a rather convoluted way:

- if DIVREM is legal, expand to DIVREM
- if DIVREM has a custom lowering, expand to DIVREM
- if DIVREM libcall is defined and a remainder from the same division is
  computed elsewhere, expand to a DIVREM libcall
- else, expand to a DIV libcall

This had the undesirable effect that if both DIV and DIVREM are implemented
as libcalls, then ISD::UDIV and ISD::SDIV are expanded to the heavier DIVREM
libcall, even when the remainder isn't used.

The new code adds a new LegalizeAction, TargetLoweringBase::LibCall, so that
backends can directly control whether they prefer an expansion or a conversion
to a libcall. This makes the generic lowering code even more generic,
allowing its reuse in a wider range of target-specific configurations.

The useful effect is that ARM backend will now generate a call
to __aeabi_{i,u}div rather than __aeabi_{i,u}divmod in cases where
it doesn't need the remainder. There's no functional change outside
the ARM backend.

Reviewers: t.p.northover, rengolin

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

Differential Revision: http://reviews.llvm.org/D13862

llvm-svn: 250826
2015-10-20 13:14:52 +00:00
Igor Breger 21296d230a AVX512: Implemented encoding and intrinsics for VPBROADCASTB/W/D/Q instructions.
Differential Revision: http://reviews.llvm.org/D13884

llvm-svn: 250819
2015-10-20 11:56:42 +00:00
Andrea Di Biagio 9a85b7abe0 [x86] Fix AVX maskload/store intrinsic prototypes.
The mask value type for maskload/maskstore GCC builtins is never a vector of
packed floats/doubles.

This patch fixes the following issues:
1. The mask argument for builtin_ia32_maskloadpd and builtin_ia32_maskstorepd
   should be of type llvm_v2i64_ty and not llvm_v2f64_ty.
2. The mask argument for builtin_ia32_maskloadpd256 and
   builtin_ia32_maskstorepd256 should be of type llvm_v4i64_ty and not
   llvm_v4f64_ty.
3. The mask argument for builtin_ia32_maskloadps and builtin_ia32_maskstoreps
   should be of type llvm_v4i32_ty and not llvm_v4f32_ty.
4. The mask argument for builtin_ia32_maskloadps256 and
   builtin_ia32_maskstoreps256 should be of type llvm_v8i32_ty and not
   llvm_v8f32_ty.

Differential Revision: http://reviews.llvm.org/D13776

llvm-svn: 250817
2015-10-20 11:20:13 +00:00
Matt Arsenault 8f18917a90 AMDGPU: Stop reserving v[254:255]
This wasn't doing anything useful. They weren't explicitly used
anywhere, and the RegScavenger ignores reserved registers.

This for some reason caused a random scheduling change in the test.
Getting the check lines to pass is too frustrating, and there's probably
not too much value in checking the vector case's operands N times.

llvm-svn: 250794
2015-10-20 03:59:58 +00:00
JF Bastien c8f89e86d5 WebAssembly: fix call/return syntax.
They are now typeless, unlike other operations.

llvm-svn: 250793
2015-10-20 01:26:54 +00:00
JF Bastien 3b0177c542 WebAssembly: fix syntax for br_if.
llvm-svn: 250777
2015-10-20 00:37:42 +00:00
Cong Hou 7745dbc5c4 Enhance loop rotation with existence of profile data in MachineBlockPlacement pass.
Currently, in MachineBlockPlacement pass the loop is rotated to let the best exit to be the last BB in the loop chain, to maximize the fall-through from the loop to outside. With profile data, we can determine the cost in terms of missed fall through opportunities when rotating a loop chain and select the best rotation. Basically, there are three kinds of cost to consider for each rotation:

1. The possibly missed fall through edge (if it exists) from BB out of the loop to the loop header.
2. The possibly missed fall through edges (if they exist) from the loop exits to BB out of the loop.
3. The missed fall through edge (if it exists) from the last BB to the first BB in the loop chain.

Therefore, the cost for a given rotation is the sum of costs listed above. We select the best rotation with the smallest cost. This is only for PGO mode when we have more precise edge frequencies.

Differential revision: http://reviews.llvm.org/D10717

llvm-svn: 250754
2015-10-19 23:16:40 +00:00
Jun Bum Lim d3548303ec [AArch64]Merge halfword loads into a 32-bit load
Convert two halfword loads into a single 32-bit word load with bitfield extract
instructions. For example :
  ldrh w0, [x2]
  ldrh w1, [x2, #2]
becomes
  ldr w0, [x2]
  ubfx w1, w0, #16, #16
  and  w0, w0, #ffff

llvm-svn: 250719
2015-10-19 18:34:53 +00:00
Krzysztof Parzyszek db8677067c [Hexagon] Delay emission of CFI instructions
Emit the CFI instructions after all code transformation have been done.
This will avoid any interference between CFI instructions and packetization.

llvm-svn: 250714
2015-10-19 17:46:01 +00:00
Asiri Rathnayake 1040a53be3 Fix mapping of @llvm.arm.ssat/usat intrinsics to ssat/usat instructions
The mapping of these two intrinsics in ARMInstrInfo.td had a small
omission which lead to their operands not being validated/transformed
before being lowered into usat and ssat instructions. This can cause
incorrect instructions to be emitted.

I've also added tests for the remaining two saturating arithmatic
intrinsics @llvm.arm.qadd and @llvm.arm.qsub as they are missing
codegen tests.

llvm-svn: 250697
2015-10-19 11:44:24 +00:00
Simon Pilgrim 4708060e94 [X86][SSE] Add vector bit rotation tests.
llvm-svn: 250656
2015-10-18 12:54:37 +00:00
Asaf Badouh 696e8e0bb7 [X86][AVX512DQ] add scalar fpclass
Differential Revision: http://reviews.llvm.org/D13769

llvm-svn: 250650
2015-10-18 11:04:38 +00:00
Igor Breger cbb9550537 AVX512: Lowering i8/i16 vector CTLZ using the dword LZCNT vector instruction
Differential Revision: http://reviews.llvm.org/D13632

llvm-svn: 250649
2015-10-18 09:56:39 +00:00
Simon Pilgrim 4773763bb0 [X86][XOP] Add VPROT rotate by immediate intrinsics tests
llvm-svn: 250618
2015-10-17 18:21:53 +00:00
Simon Pilgrim 5b65f28fe7 [X86][FastISel] Teach how to select SSE4A nontemporal stores.
Add FastISel support for SSE4A scalar float / double non-temporal stores

Follow up to D13698

Differential Revision: http://reviews.llvm.org/D13773

llvm-svn: 250610
2015-10-17 13:04:42 +00:00
Colin LeMahieu 68d155be8e [Hexagon] Reverting test file change.
llvm-svn: 250601
2015-10-17 01:58:51 +00:00
Colin LeMahieu 7c9587136d [Hexagon] Adding skeleton of HVX extension instructions.
llvm-svn: 250600
2015-10-17 01:33:04 +00:00
JF Bastien 3428ed4f53 WebAssembly: don't omit dead vregs from locals
Summary:
This is a temporary hack until we get around to remapping the vreg
numbers to local numbers. Dead vregs cause bad numbering and make
consumers sad.

We could also just look at debug info an use named locals instead, but
vregs have to work properly anyways so there!

Reviewers: binji, sunfish

Subscribers: jfb, llvm-commits, dschuff

Differential Revision: http://reviews.llvm.org/D13839

llvm-svn: 250594
2015-10-17 00:25:38 +00:00
JF Bastien 4f43e80ece WebAssembly: fix the syntax for comparisons
Summary: It has also slightly changed.

Reviewers: binji

Subscribers: jfb, dschuff, llvm-commits, sunfish

Differential Revision: http://reviews.llvm.org/D13837

llvm-svn: 250591
2015-10-17 00:12:29 +00:00
Joseph Tremoulet 55b51e9dcc [WinEH] Fix eh.exceptionpointer intrinsic lowering
Summary:
Some shared code for handling eh.exceptionpointer and eh.exceptioncode
needs to not share the part that truncates to 32 bits, which is intended
just for exception codes.

Reviewers: rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D13747

llvm-svn: 250588
2015-10-17 00:08:08 +00:00
Reid Kleckner 28e490342b [WinEH] Fix stack alignment in funclets and ParentFrameOffset calculation
Our previous value of "16 + 8 + MaxCallFrameSize" for ParentFrameOffset
is incorrect when CSRs are involved. We were supposed to have a test
case to catch this, but it wasn't very rigorous.

The main effect here is that calling _CxxThrowException inside a
catchpad doesn't immediately crash on MOVAPS when you have an odd number
of CSRs.

llvm-svn: 250583
2015-10-16 23:43:27 +00:00
Sanjay Patel bbd524496c [x86] promote 'add nsw' to a wider type to allow more combines
The motivation for this patch starts with PR20134:
https://llvm.org/bugs/show_bug.cgi?id=20134

void foo(int *a, int i) {
  a[i] = a[i+1] + a[i+2];
}

It seems better to produce this (14 bytes):

movslq	%esi, %rsi
movl	0x4(%rdi,%rsi,4), %eax
addl	0x8(%rdi,%rsi,4), %eax
movl	%eax, (%rdi,%rsi,4)

Rather than this (22 bytes):

leal	0x1(%rsi), %eax
cltq             
leal	0x2(%rsi), %ecx      
movslq	%ecx, %rcx     
movl	(%rdi,%rcx,4), %ecx
addl	(%rdi,%rax,4), %ecx
movslq	%esi, %rax       
movl	%ecx, (%rdi,%rax,4)

The most basic problem (the first test case in the patch combines constants) should also be fixed in InstCombine, 
but it gets more complicated after that because we need to consider architecture and micro-architecture. For
example, AArch64 may not see any benefit from the more general transform because the ISA solves the sexting in
hardware. Some x86 chips may not want to replace 2 ADD insts with 1 LEA, and there's an attribute for that: 
FeatureSlowLEA. But I suspect that doesn't go far enough or maybe it's not getting used when it should; I'm 
also not sure if FeatureSlowLEA should also mean "slow complex addressing mode".

I see no perf differences on test-suite with this change running on AMD Jaguar, but I see small code size
improvements when building clang and the LLVM tools with the patched compiler.

A more general solution to the sext(add nsw(x, C)) problem that works for multiple targets is available
in CodeGenPrepare, but it may take quite a bit more work to get that to fire on all of the test cases that
this patch takes care of.

Differential Revision: http://reviews.llvm.org/D13757

llvm-svn: 250560
2015-10-16 22:14:12 +00:00
Joseph Tremoulet d11a998e81 [WinEH] Fix CatchRetSuccessorColorMap accounting
Summary:
We now use the block for the catchpad itself, rather than its normal
successor, as the funclet entry.
Putting the normal successor in the map leads downstream funclet
membership computations to erroneous results.

Reviewers: majnemer, rnk

Subscribers: rnk, llvm-commits

Differential Revision: http://reviews.llvm.org/D13798

llvm-svn: 250552
2015-10-16 21:22:54 +00:00
Andrew Kaylor 09b39acc03 Fix assertion failure with fp128 to unsigned i64 conversion
Patch by Mitch Bodart

Differential Revision: http://reviews.llvm.org/D13780

llvm-svn: 250550
2015-10-16 20:39:20 +00:00
Krzysztof Parzyszek a7c5f0409c [Hexagon] Split double registers
llvm-svn: 250549
2015-10-16 20:38:54 +00:00
Krzysztof Parzyszek 5b7dd0cdf9 [Hexagon] Merge adjacent stores
llvm-svn: 250542
2015-10-16 19:43:56 +00:00
JF Bastien 6126d2b883 WebAssembly: fix load/store syntax
Summary: The syntax has changed a bit recently.

Reviewers: binji

Subscribers: llvm-commits, jfb, sunfish, dschuff

Differential Revision: http://reviews.llvm.org/D13821

llvm-svn: 250535
2015-10-16 18:24:42 +00:00
Joseph Tremoulet 53e9cbd95a [WinEH] Fix endpad coloring/numbering
Summary:
When a cleanup's cleanupendpad or cleanupret targets a catchendpad, stop
trying to propagate the cleanup's parent's color to the catchendpad, since
what's needed is the cleanup's grandparent's color and the catchendpad
will get that color from the catchpad linkage already.  We already had
this exclusion for invokes, but were missing it for
cleanupendpad/cleanupret.

Also add a missing line that tags cleanupendpads' states in the
EHPadStateMap, without with lowering invokes that target cleanupendpads
which unwind to other handlers (and so don't have the -1 state) will fail.

This fixes the reduced IR repro in PR25163.


Reviewers: majnemer, andrew.w.kaylor, rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D13797

llvm-svn: 250534
2015-10-16 18:08:16 +00:00
Charlie Turner 434d4599d4 [AArch64] Implement vector splitting on UADDV.
Summary: Fixes PR25056.

Reviewers: mcrosier, junbuml, jmolloy

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: http://reviews.llvm.org/D13466

llvm-svn: 250520
2015-10-16 15:38:25 +00:00
Craig Topper 09b6598572 [X86] Add fxsr feature flag for fxsave/fxrestore instructions.
llvm-svn: 250497
2015-10-16 06:03:09 +00:00
JF Bastien 1d20a5e9e8 WebAssembly: update syntax
Summary:
Follow the same syntax as for the spec repo. Both have evolved slightly
independently and need to converge again.

This, along with wasmate changes, allows me to do the following:

  echo "int add(int a, int b) { return a + b; }" > add.c
  ./out/bin/clang -O2 -S --target=wasm32-unknown-unknown add.c -o add.wack
  ./experimental/prototype-wasmate/wasmate.py add.wack > add.wast
  ./sexpr-wasm-prototype/out/sexpr-wasm add.wast -o add.wasm
  ./sexpr-wasm-prototype/third_party/v8-native-prototype/v8/v8/out/Release/d8 -e "print(WASM.instantiateModule(readbuffer('add.wasm'), {print:print}).add(42, 1337));"

As you'd expect, the d8 shell prints out the right value.

Reviewers: sunfish

Subscribers: jfb, llvm-commits, dschuff

Differential Revision: http://reviews.llvm.org/D13712

llvm-svn: 250480
2015-10-16 00:53:49 +00:00
JF Bastien 2cdd5e4710 x86: preserve flags when folding atomic operations
D4796 taught LLVM to fold some atomic integer operations into a single
instruction. The pattern was unaware that the instructions clobbered
flags. I fixed some of this issue in D13680 but had missed INC/DEC.

This patch adds the missing EFLAGS definition.

llvm-svn: 250438
2015-10-15 18:24:52 +00:00
Kevin B. Smith 89760f04f9 Change test to use FileCheck rather than grep.
Differential Revision: http://reviews.llvm.org/D13751

llvm-svn: 250431
2015-10-15 17:05:12 +00:00
JF Bastien 5b327712b0 x86 FP atomic codegen: don't drop globals, stack
Summary:
x86 codegen is clever about generating good code for relaxed
floating-point operations, but it was being silly when globals and
immediates were involved, forgetting where the global was and
loading/storing from/to the wrong place. The same applied to hard-coded
address immediates.

Don't let it forget about the displacement.

This fixes https://llvm.org/bugs/show_bug.cgi?id=25171

A very similar bug when doing floating-points atomics to the stack is
also fixed by this patch.

This fixes https://llvm.org/bugs/show_bug.cgi?id=25144

Reviewers: pete

Subscribers: llvm-commits, majnemer, rsmith

Differential Revision: http://reviews.llvm.org/D13749

llvm-svn: 250429
2015-10-15 16:46:29 +00:00
Daniel Sanders 8008de5551 [mips][mips16] MIPS16 is not a CPU/Architecture but is an ASE.
Summary:
The -mcpu=mips16 option caused the Integrated Assembler to crash because
it couldn't figure out the architecture revision number to write to the
.MIPS.abiflags section. This CPU definition has been removed because, like
microMIPS, MIPS16 is an ASE to a base architecture.

Reviewers: vkalintiris

Subscribers: rkotler, llvm-commits, dsanders

Differential Revision: http://reviews.llvm.org/D13656

llvm-svn: 250407
2015-10-15 14:34:23 +00:00
Igor Breger d7bae451de AVX512: Implemented DAG lowering for shuff62x2/shufi62x2 instructions ( shuffle packed values at 128-bit granularity )
Differential Revision: http://reviews.llvm.org/D13648

llvm-svn: 250400
2015-10-15 13:29:07 +00:00
Igor Breger b4bb190eed AVX512: Implemented encoding and intrinsics for vpternlogd/q.
Differential Revision: http://reviews.llvm.org/D13768

llvm-svn: 250396
2015-10-15 12:33:24 +00:00
Elena Demikhovsky ecff21b297 AVX-512: Fixed a bug in shuffle lowering 32-bit mode
AVX-512 bit shuffle fails on 32 bit since we create a vector of 64-bit constants.
I split 8x64-bit const vector to 16x32 on 32-bit mode.

Differential Revision: http://reviews.llvm.org/D13644

llvm-svn: 250390
2015-10-15 11:35:33 +00:00
Andrea Di Biagio 6a61cecef0 [x86] Merge test pr24562.ll into x86-fold-pshufb.ll. NFC.
llvm-svn: 250387
2015-10-15 09:54:25 +00:00
Akira Hatanaka 8ad7399f8e [MachO] Stop generating *coal* sections.
Recommit r250342: move coal-sections-powerpc.s to subdirectory for powerpc.

Some background on why we don't have to use *coal* sections anymore:
Long ago when C++ was new and "weak" had not been standardized, an attempt was
made in cctools to support C++ inlines that can be coalesced by putting them
into their own section (TEXT/textcoal_nt instead of TEXT/text).

The current macho linker supports the weak-def bit on any symbol to allow it to
be coalesced, but the compiler still puts weak-def functions/data into alternate
section names, which the linker must map back to the base section name.

This patch makes changes that are necessary to prevent the compiler from using
the "coal" sections and have it use the non-coal sections instead when the
target architecture is not powerpc:

TEXT/textcoal_nt instead use TEXT/text
TEXT/const_coal instead use TEXT/const
DATA/datacoal_nt instead use DATA/data

If the target is powerpc, we continue to use the *coal* sections since anyone
targeting powerpc is probably using an old linker that doesn't have support for
the weak-def bits.

Also, have the assembler issue a warning if it encounters a *coal* section in
the assembly file and inform the users to use the non-coal sections instead.

rdar://problem/14265330

Differential Revision: http://reviews.llvm.org/D13188

llvm-svn: 250370
2015-10-15 05:28:38 +00:00
Quentin Colombet 5084e44d71 [ARM] Make sure we do not dereference the end iterator when accessing debug
information.
Although the problem was always here, it would only be exposed when
shrink-wrapping is enable.

rdar://problem/23110493

llvm-svn: 250352
2015-10-15 00:41:26 +00:00
Akira Hatanaka 276332b47f Revert r250349.
Test case coal-sections-powerpc.s is still failing on some buildbots.

llvm-svn: 250351
2015-10-15 00:11:03 +00:00
Akira Hatanaka 1cea644114 [MachO] Stop generating *coal* sections.
Recommit r250342: add -arch=ppc32 to the RUN lines of powerpc tests.

Some background on why we don't have to use *coal* sections anymore:
Long ago when C++ was new and "weak" had not been standardized, an attempt was
made in cctools to support C++ inlines that can be coalesced by putting them
into their own section (TEXT/textcoal_nt instead of TEXT/text).

The current macho linker supports the weak-def bit on any symbol to allow it to
be coalesced, but the compiler still puts weak-def functions/data into alternate
section names, which the linker must map back to the base section name.

This patch makes changes that are necessary to prevent the compiler from using
the "coal" sections and have it use the non-coal sections instead when the
target architecture is not powerpc:

TEXT/textcoal_nt instead use TEXT/text
TEXT/const_coal instead use TEXT/const
DATA/datacoal_nt instead use DATA/data

If the target is powerpc, we continue to use the *coal* sections since anyone
targeting powerpc is probably using an old linker that doesn't have support for
the weak-def bits.

Also, have the assembler issue a warning if it encounters a *coal* section in
the assembly file and inform the users to use the non-coal sections instead.

rdar://problem/14265330

Differential Revision: http://reviews.llvm.org/D13188

llvm-svn: 250349
2015-10-14 23:48:10 +00:00
Akira Hatanaka d58d347e42 Revert r250342.
Investigate why coal-sections-powerpc.s is failing on some buildbots.

llvm-svn: 250346
2015-10-14 23:29:10 +00:00
Akira Hatanaka c078ae3e4f [MachO] Stop generating *coal* sections.
Some background on why we don't have to use *coal* sections anymore:
Long ago when C++ was new and "weak" had not been standardized, an attempt was
made in cctools to support C++ inlines that can be coalesced by putting them
into their own section (TEXT/textcoal_nt instead of TEXT/text).

The current macho linker supports the weak-def bit on any symbol to allow it to
be coalesced, but the compiler still puts weak-def functions/data into alternate
section names, which the linker must map back to the base section name.

This patch makes changes that are necessary to prevent the compiler from using
the "coal" sections and have it use the non-coal sections instead when the
target architecture is not powerpc:

TEXT/textcoal_nt instead use TEXT/text
TEXT/const_coal instead use TEXT/const
DATA/datacoal_nt instead use DATA/data

If the target is powerpc, we continue to use the *coal* sections since anyone
targeting powerpc is probably using an old linker that doesn't have support for
the weak-def bits.

Also, have the assembler issue a warning if it encounters a *coal* section in
the assembly file and inform the users to use the non-coal sections instead.

rdar://problem/14265330

Differential Revision: http://reviews.llvm.org/D13188

llvm-svn: 250342
2015-10-14 22:45:36 +00:00
Sanjay Patel e2b528074d add x86 codegen tests for 'add nsw' followed by 'sext'
llvm-svn: 250332
2015-10-14 21:47:03 +00:00
Bill Schmidt 048cc97fb1 [PowerPC] Fix invalid lxvdsx optimization (PR25157)
PR25157 identifies a bug where a load plus a vector shuffle is
incorrectly converted into an LXVDSX instruction.  That optimization
is only valid if the load is of a doubleword, and in the noted case,
it was not.  This corrects that problem.

Joint patch with Eric Schweitz, who provided the bugpoint-reduced test
case.

llvm-svn: 250324
2015-10-14 20:45:00 +00:00
Andrea Di Biagio c47edbef4c [x86][FastISel] Teach how to select nontemporal stores.
This patch teaches x86 fast-isel how to select nontemporal stores.

On x86, we can use MOVNTI for nontemporal stores of doublewords/quadwords.
Instructions (V)MOVNTPS/PD/DQ can be used for SSE2/AVX aligned nontemporal
vector stores.

Before this patch, fast-isel always selected 'movd/movq' instead of 'movnti'
for doubleword/quadword nontemporal stores. In the case of nontemporal stores
of aligned vectors, fast-isel always selected movaps/movapd/movdqa instead of
movntps/movntpd/movntdq.

With this patch, if we use SSE2/AVX intrinsics for nontemporal stores we now
always get the expected (V)MOVNT instructions.
The lack of fast-isel support for nontemporal stores was spotted when analyzing
the -O0 codegen for nontemporal stores.

Differential Revision: http://reviews.llvm.org/D13698

llvm-svn: 250285
2015-10-14 10:03:13 +00:00
Joseph Tremoulet 28c89bbb36 [WinEH] Add CoreCLR EH table emission
Summary:
Emit the handler and clause locations immediately after the standard
xdata.
Clauses are emitted in the same order and format used to communiate them
to the CLR Execution Engine.
Add a lit test to verify correct table generation on a small but
interesting example function.

Reviewers: majnemer, andrew.w.kaylor, rnk

Subscribers: pgavlin, AndyAyers, llvm-commits

Differential Revision: http://reviews.llvm.org/D13451

llvm-svn: 250219
2015-10-13 20:18:27 +00:00
Matt Arsenault e5d9515fb7 DAGCombiner: Don't stop finding better chain on 2 aliases
The comment says this was stopped because it was unlikely to be
profitable. This is not true if you want to combine vector loads
with multiple components.

For a simple case that looks like

t0 = load t0 ...
t1 = load t0 ...
t2 = load t0 ...
t3 = load t0 ...

t4 = store t0:1, t0:1
  t5 = store t4, t1:0
    t6 = store t5, t2:0
	  t7 = store t6, t3:0

We want to get all of these stores onto a chain
that is a TokenFactor of these N loads. This mostly
solves the AMDGPU merge-stores.ll regressions
with -combiner-alias-analysis for merging vector
stores of vector loads.

llvm-svn: 250138
2015-10-13 00:49:00 +00:00