Commit Graph

29684 Commits

Author SHA1 Message Date
b7239d3aa5 R600: Make FMIN/MAXNUM legal on all asics
v2: Add tests

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
reviewer: arsenm

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234716 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-12 23:45:05 +00:00
054db7df5b [MC] Write padding into fragments when -mc-relax-all flag is used
Summary:
When instruction bundling is enabled and the -mc-relax-all flag is
set, we can write bundle padding directly into fragments and avoid
creating large number of fragments significantly reducing LLVM MC
memory usage.

Test Plan: Regression test attached

Reviewers: eliben

Subscribers: jfb, mseaborn

Differential Revision: http://reviews.llvm.org/D8072

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234714 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-12 23:42:25 +00:00
2ae6c65416 [Orc] During module partitioning, rename anonymous and asm-private globals.
If they're not (re)named, these globals will fail to resolve when the
partitioned modules are linked.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234707 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-12 20:05:51 +00:00
ad96655905 [PowerPC] Really iterate over all loops in PPCLoopDataPrefetch/PPCLoopPreIncPrep
When I fixed these a couple of days ago to iterate over all loops, not just
depth == 1 loops, I inadvertently made it such that we'd only look at the first
top-level loop. Make sure that we really look at all of them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234705 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-12 17:18:56 +00:00
e0f4a11a89 [LoopUnrollRuntime] Clean up a predicate.
Clean up a predicate I added in r229731, fix the relevant comment and
add a test case.  The earlier version is confusing to read and was also
buggy (probably not a coincidence) till Alexey fixed it in r233881.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234701 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-12 01:24:01 +00:00
1cea397876 [PowerPC] Disable part-word atomics on the P7
As it turns out, even though these are part of ISA 2.06, the P7 does not
support them (or, at least, not any P7s we're tested so far).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234686 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-11 13:40:36 +00:00
9ca031b6c6 Add direct moves to/from VSR and exploit them for FP/INT conversions
This patch corresponds to review:
http://reviews.llvm.org/D8928

It adds direct move instructions to/from VSX registers to GPR's. These are
exploited for FP <-> INT conversions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234682 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-11 10:40:42 +00:00
ff49ef7838 [PowerPC] Fix PPCLoopPreIncPrep for depth > 1 loops
This pass had the same problem as the data-prefetching pass: it was only
checking for depth == 1 loops in practice. Fix that, add some debugging
statements, and make sure that, when we grab an AddRec, it is for the loop we
expect.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234670 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-11 00:33:08 +00:00
d2069333ee [CodeGen] Split -enable-global-merge into ARM and AArch64 options.
Currently, there's a single flag, checked by the pass itself.
It can't force-enable the pass (and is on by default), because it
might not even have been created, as that's the targets decision.
Instead, have separate explicit flags, so that the decision is
consistently made in the target.

Keep the flag as a last-resort "force-disable GlobalMerge" for now,
for backwards compatibility.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234666 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-11 00:06:36 +00:00
c127686d0e [WinEH] Recognize SEH finally block inserted by the frontend
This allows winehprepare to build sensible llvm.eh.actions calls for SEH
finally blocks.  The pattern matching in this change is brittle and
should be replaced with something more robust soon.  In the meantime,
this will let us write the code that produces __C_specific_handler xdata
tables, which we need regardless of how we decide to get finally blocks
through EH preparation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234663 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 23:12:29 +00:00
f894c7ecb2 [RewriteStatepointsForGC] test case missing from 234657
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234658 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 22:58:39 +00:00
d92e9ef170 [RewriteStatepointsForGC] Use an actual liveness algorithm
When rewriting statepoints to make relocations explicit, we need to have a conservative but consistent notion of where a particular pointer is live at a particular site. The old code just used dominance, which is correct, but decidedly more conservative then it needed to be. This patch implements a simple dataflow algorithm that's run one per function (well, twice counting fixup after base pointer insertion). There's still lots of room to make this faster, but it's fast enough for all practical purposes today.

Differential Revision: http://reviews.llvm.org/D8674



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234657 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 22:53:14 +00:00
82374f6b8a [RewriteStatepointsForGC] Preprocess the IR to remove unreachable blocks and single entry phis
Two related small changes:

    Various dominance based queries about liveness can get confused if we're talking about unreachable blocks. To avoid reasoning about such cases, just remove them before rewriting statepoints.
    Remove single entry phis (likely left behind by LCSSA) to reduce the number of live values.

Both of these are motivated by http://reviews.llvm.org/D8674 which will be submitted shortly.

Differential Revision: http://reviews.llvm.org/D8675



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234651 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 22:07:04 +00:00
cb148c8541 [RewriteStatepointsForGC] Limited support for vectors of pointers
This patch adds limited support for inserting explicit relocations when there's a vector of pointers live over the statepoint. This doesn't handle the case where the vector contains a mix of base and non-base pointers; that's future work.

The current implementation just scalarizes the vector over the gc.statepoint before doing the explicit rewrite. An alternate approach would be to plumb the vector all the way though the backend lowering, but doing that appears challenging. In particular, the size of the indirect spill slot is currently assumed to be sizeof(pointer) throughout the backend.

In practice, this is enough to allow running the SLP and Loop vectorizers before RewriteStatepointsForGC.

Differential Revision: http://reviews.llvm.org/D8671



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234647 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 21:48:25 +00:00
8aca90e5b6 [InstCombine][CodeGenPrep] Create llvm.uadd.with.overflow in CGP.
Summary:
This change moves creating calls to `llvm.uadd.with.overflow` from
InstCombine to CodeGenPrep.  Combining overflow check patterns into
calls to the said intrinsic in InstCombine inhibits optimization because
it introduces an intrinsic call that not all other transforms and
analyses understand.

Depends on D8888.

Reviewers: majnemer, atrick

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8889

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234638 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 21:07:09 +00:00
79db0a6fd9 Avoid spewing binary to stdout in some filetype=obj tests
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234627 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 19:36:55 +00:00
dc0ca89635 use update_llc_test_checks.py to tighten checking
test features, not CPUs

remove unnecessary cruft


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234622 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 18:31:42 +00:00
10d1d8a3bd [WinEH] Try to make outlining invokes work a little better
WinEH currently turns invokes into calls. Long term, we will reconsider
this, but for now, make sure we remap the operands and clone the
successors of the new terminator.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234608 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 16:26:42 +00:00
d4f643a5df [PowerPC] Prefetching should also consider depth > 1 loops
Iterating over loops from the LoopInfo instance only provides top-level loops.
We need to search the whole tree of loops to find the inner ones.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234603 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 15:05:02 +00:00
bb11bbe297 [mips] [IAS] Make the mips-expansions-bad.s test more readable. NFC.
Move the check lines below the code lines and change the indentation from 8
spaces to 2 spaces.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234584 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 10:46:59 +00:00
5733100450 Divergence analysis for GPU programs
Summary:
Some optimizations such as jump threading and loop unswitching can negatively
affect performance when applied to divergent branches. The divergence analysis
added in this patch conservatively estimates which branches in a GPU program
can diverge. This information can then help LLVM to run certain optimizations
selectively.

Test Plan: test/Analysis/DivergenceAnalysis/NVPTX/diverge.ll

Reviewers: resistor, hfinkel, eliben, meheff, jholewinski

Subscribers: broune, bjarke.roune, madhur13490, tstellarAMD, dberlin, echristo, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D8576

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234567 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 05:03:50 +00:00
36f934a207 [PowerPC] Don't crash on PPC32 i64 fp_to_uint on modern cores
When we have an instruction for this (and, thus, don't generate a runtime
call), we need to custom type legalize this (in a trivial way, just as we do
for fp_to_sint).

Fixes PR23173.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234561 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 03:39:00 +00:00
1810ca3110 [AArch64] Promote f16 operations to f32.
For the most common ones (such as fadd), we already did the promotion.
Do the same thing for all the others.

Currently, we'll just crash/assert on all these operations, as
there's no hardware or libcall support whatsoever.

f16 (half) is specified as an interchange - not arithmetic - format,
and is expected to be promoted to single-precision for arithmetic
operations.

While there, teach the legalizer about promoting some of the (mostly
floating-point) operations that we never needed before.

Differential Revision: http://reviews.llvm.org/D8648
See related discussion on the thread for: http://reviews.llvm.org/D8755


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234550 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 00:08:48 +00:00
c58b8f0b65 Add LLVM support for remaining integer divide and permute instructions from ISA 2.06
This is the patch corresponding to review:
http://reviews.llvm.org/D8406

It adds some missing instructions from ISA 2.06 to the PPC back end.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234546 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-09 23:54:37 +00:00
66649e00c9 [CodeGen] Combine concat_vector of trunc'd scalar to scalar_to_vector.
We already do:
  concat_vectors(scalar, undef) -> scalar_to_vector(scalar)
When the scalar is legal.
When it's not, but is a truncated legal scalar, we can also do:
  concat_vectors(trunc(scalar), undef) -> scalar_to_vector(scalar)
Which is equivalent, since the upper lanes are undef anyway.
While there, teach the combine to look at more than 2 operands.

Differential Revision: http://reviews.llvm.org/D8883


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234530 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-09 20:04:47 +00:00
117bf240ef [AArch64][FastISel] Fix integer extend optimization.
The integer extend optimization tries to fold the extend into the load
instruction. This requires us to identify if the extend has already been
emitted or not and act accordingly on it.

The check that was originally performed for this was not sufficient. Besides
checking the ValueMap for a mapped register we also need to check if the
virtual register has already an associated machine instruction that defines it.

This fixes rdar://problem/20470788.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234529 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-09 20:00:46 +00:00
57a24199de Revert "Refactoring and enhancement to FMA combine."
This reverts commit r234513. It was failing on the bots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234518 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-09 18:29:32 +00:00
ef67194fd2 Refactoring and enhancement to FMA combine.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234513 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-09 17:55:26 +00:00
28c2fda9df [ARM] support for Cortex-R4/R4F
Currently, llvm (backend) doesn't know cortex-r4, even though it is the
default target for armv7r. Using "--target=armv7r-arm-none-eabi" provokes
'cortex-r4' is not a recognized processor for this target' by llvm.
This patch adds support for cortex-r4 and, very closely related, r4f.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234486 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-09 14:07:28 +00:00
2a6ad5bfb2 [AArch64] Add support for dynamic stack alignment
Differential Revision: http://reviews.llvm.org/D8876



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234471 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-09 08:49:47 +00:00
64008ef318 [AArch64] Remove redundant -march option. Also fix a think-o from r234462.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234467 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-09 05:34:57 +00:00
7ca40334f1 Not all triples put _ before function names. Specify a triple to make this test pass on Linux.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234466 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-09 05:31:32 +00:00
174f04eefb [AArch64] Teach AArch64TargetLowering::getOptimalMemOpType to consider alignment
restrictions when choosing a type for small-memcpy inlining in
SelectionDAGBuilder.

This ensures that the loads and stores output for the memcpy won't be further
expanded during legalization, which would cause the total number of instructions
for the memcpy to exceed (often significantly) the inlining thresholds.

<rdar://problem/17829180>



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234462 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-09 03:40:33 +00:00
2c3c562b03 Use option -march instead of -mtriple to avoid overconditionalizing the test.
This fixes r234439, which was committed to fix the test failures caused by
r234430.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234451 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 23:02:45 +00:00
0400513fd3 Pass -mtriple to llc to appease buildbot.
This fixes the test case I committed in r234430.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234439 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 21:30:48 +00:00
a9180a2fac [WinEH] Minor bug fixes.
Fixed insert point for allocas created for demoted values.
Clear the nested landing pad list after it has been processed.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234433 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 20:57:22 +00:00
522877813a [DAGCombine] Fix a bug in MergeConsecutiveStores.
The bug manifests when there are two loads and two stores chained as follows in
a DAG,

(ld v3f32) -> (st f32) -> (ld v3f32) -> (st f32)

and the stores' values are extracted from the preceding vector loads.

MergeConsecutiveStores would replace the first store in the chain with the
merged vector store, which would create a cycle between the merged store node
and the last load node that appears in the chain.

This commits fixes the bug by replacing the last store in the chain instead.

rdar://problem/20275084

Differential Revision: http://reviews.llvm.org/D8849


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234430 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 20:34:53 +00:00
cd13a3808a [LoopAccesses] Allow analysis to complete in the presence of uniform stores
(Re-apply r234361 with a fix and a testcase for PR23157)

Both run-time pointer checking and the dependence analysis are capable
of dealing with uniform addresses. I.e. it's really just an orthogonal
property of the loop that the analysis computes.

Run-time pointer checking will only try to reason about SCEVAddRec
pointers or else gives up. If the uniform pointer turns out the be a
SCEVAddRec in an outer loop, the run-time checks generated will be
correct (start and end bounds would be equal).

In case of the dependence analysis, we work again with SCEVs. When
compared against a loop-dependent address of the same underlying object,
the difference of the two SCEVs won't be constant. This will result in
returning an Unknown dependence for the pair.

When compared against another uniform access, the difference would be
constant and we should return the right type of dependence
(forward/backward/etc).

The changes also adds support to query this property of the loop and
modify the vectorizer to use this.

Patch by Ashutosh Nema!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234424 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 17:48:40 +00:00
7e2bc24e05 [ARM] make vminnm/vmaxnm work with ?le, ?ge and no-nans-fp-math
Because -menable-no-nans causes fcmp conditions to be rewritten
without 'o' or 'u' the recognition code in needs to cope. Also
extended it to handle 'le' and 'ge.

Differential Revision: http://reviews.llvm.org/D8725


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234421 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 17:18:28 +00:00
912be27c05 fixed to test features, not CPU models
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234413 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 16:51:42 +00:00
739ca842aa [mips] [IAS] Do not generate redundant move when expanding lw/sw with symbol.
Summary:
Even though there is no 2nd register operand in the "lw/sw $8, symbol" case, we still try to find one, 
and we end up with $0, which makes us generate an unnecessary "addu $8, $8, $0" (a.k.a. "move $8, $8").

We can avoid this by checking if the 2nd register operand is different from $0, before generating the addu.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8055

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234406 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 13:52:41 +00:00
f716ca43ca [mips] [IAS] Add support for the BNEZL and BEQZL pseudo-instructions.
Summary:
They are of the form "bnezl/beqzl $rs, offset" and expand to "bnel/beql $rs, $zero, offset".

These instructions are used in Linux inline assembly.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8540

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234401 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 12:15:05 +00:00
541279fdf9 Write the section header in the end.
One could make the argument for writing it immediately after the ELF header,
but writing it in the middle of the sections like we were doing just makes
it harder for no reason.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234400 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 11:41:24 +00:00
a7512d1d4a [ARM][Debug Info] Restore emitting of .cfi_def_cfa_offset for functions without stack frame
Summary: Looks like new code from [[ http://reviews.llvm.org/rL222057 | rL222057 ]] doesn't account for early `return` in `ARMFrameLowering::emitPrologue`, which leads to loosing `.cfi_def_cfa_offset` directive for functions without stack frame.

Reviewers: echristo, rengolin, asl, t.p.northover

Reviewed By: t.p.northover

Subscribers: llvm-commits, rengolin, aemerson

Differential Revision: http://reviews.llvm.org/D8606

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234399 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 10:10:12 +00:00
39fedc9aa2 [mips] [IAS] Remove AssemblerPredicate's from RelocPIC and RelocStatic.
Summary:
These AssemblerPredicate's are unnecessary and actually make some instructions unusable when assembling pre-MIPS32 ISAs.
For example, this was causing the IAS to reject the 'j' instruction for MIPS I-V.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8300

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234398 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 10:06:45 +00:00
b343d1cd85 Revert "[LoopAccesses] Allow analysis to complete in the presence of uniform stores"
This reverts commit r234361.

It caused PR23157.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234387 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 04:16:55 +00:00
a787066317 R600/SI: Initial support for assembler and inline assembly
This is currently considered experimental, but most of the more
commonly used instructions should work.

So far only SI has been extensively tested, CI and VI probably work too,
but may be buggy.  The current set of tests cases do not give complete
coverage, but I think it is sufficient for an experimental assembler.

See the documentation in R600Usage for more information.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234381 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 01:09:26 +00:00
434e097df8 R600/SI: Don't print offset0/offset1 DS operands when they are 0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234379 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 01:09:19 +00:00
112102c7fe AArch64: disallow "fmov sD, #-0.0" during assembly.
We weren't checking the sign of the floating point immediate before translating
it to "fmov sD, wzr". Similarly for D-regs.

Technically "movi vD.2s, #0x80, lsl #24" would work most of the time, but it's
not a blessed alias (and I don't think it should be since people expect writing
sD to zero out the high lanes, and there's no dD equivalent). So an error it is.

rdar://20455398

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234372 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-07 22:49:47 +00:00
a0834f1d87 [LoopAccesses] Allow analysis to complete in the presence of uniform stores
Both run-time pointer checking and the dependence analysis are capable
of dealing with uniform addresses. I.e. it's really just an orthogonal
property of the loop that the analysis computes.

Run-time pointer checking will only try to reason about SCEVAddRec
pointers or else gives up. If the uniform pointer turns out the be a
SCEVAddRec in an outer loop, the run-time checks generated will be
correct (start and end bounds would be equal).

In case of the dependence analysis, we work again with SCEVs. When
compared against a loop-dependent address of the same underlying object,
the difference of the two SCEVs won't be constant. This will result in
returning an Unknown dependence for the pair.

When compared against another uniform access, the difference would be
constant and we should return the right type of dependence
(forward/backward/etc).

The changes also adds support to query this property of the loop and
modify the vectorizer to use this.

Patch by Ashutosh Nema!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234361 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-07 21:46:16 +00:00