Commit Graph

29371 Commits

Author SHA1 Message Date
Ahmed Bougacha
252c120f4a [SimplifyLibCalls] Ignore nobuiltin/unavailable fortified libcalls.
We used to do this before refactorings around r225640.
Some clang users checked for _chk libcall availability using:
  __has_builtin(__builtin___memcpy_chk)
When compiling with -fno-builtin, this is always true.
When passing -ffreestanding/-mkernel, which both imply -fno-builtin, we
end up with fortified libcalls, which isn't acceptable in a freestanding
environment which only provides their non-fortified counterparts.

Until we change clang and/or teach external users to check for availability
differently, disregard the "nobuiltin" attribute and TLI::has.

Workaround for PR23093.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233776 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-01 00:45:09 +00:00
Hal Finkel
54ab6ce385 [PowerPC] FastISel can't handle i1 return values when using CR bits
Under normal circumstances, use of CR bits is disabled when running at -O0, but
it is enabled by default otherwise, and if you have optnone functions, they'll
still generally be generated with crbits turned on (because nothing else turns
them off). FastISel can't handle most things dealing with i1 values when using
CR bits, and checks for that, but was not checking the return type on
functions; we can't fast-isel function calls with i1 return values either when
using CR bits for boolean values.

Fixes PR22664.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233775 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-01 00:40:48 +00:00
David Majnemer
64386621ec [WinEH] Generate .xdata for catch handlers
This lets us catch exceptions in simple cases.

N.B. Things that do not work include (but are not limited to):
- Throwing from within a catch handler.
- Catching an object with a named catch parameter.
- 'CatchHigh' is fictitious, we aren't sure of its purpose.
- We aren't entirely efficient with regards to the number of EH states
  that we generate.
- IP-to-State tables are sensitive to the order of emission.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233767 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 22:35:44 +00:00
Duncan P. N. Exon Smith
9ce8e7ea73 Verifier: Add a testcase for verifying type refs
r233664 fixed the `Verifier` so that it doesn't crash on bad type refs.
This deserves a test!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233756 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 20:57:56 +00:00
Hal Finkel
72cce21049 [PowerPC] Don't use a vector preferred memory type at -O0
Even at -O0, we fall back to SDAG when we hit intrinsics, and if the intrinsic
is a memset/memcpy/etc. we might normally use vector types. At -O0, this is
probably not a good idea (because, if there is a bug in the lowering code,
there would be no good way to turn it off). At -O0, only use scalar preferred
types.

Related to PR22754.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233755 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 20:56:09 +00:00
Quentin Colombet
6aebd393f0 [AArch64] Enable the codegenprepare optimization that promotes operation to form
extended loads.
Implement the related target lowering hook so that the optimization has a better
estimation of the cost of an extension.

rdar://problem/19267165


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233753 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 20:52:32 +00:00
Hal Finkel
20fc6ac99e [SDAG] Handle non-integer preferred memset types for non-constant values
The existing code in getMemsetValue only handled integer-preferred types when
the fill value was not a constant. Make this more robust in two ways:

  1. If the preferred type is a floating-point value, do the mul-splat trick on
     the corresponding integer type and then bitcast.
  2. If the preferred type is a vector, do the mul-splat trick on one vector
     element, and then build a vector out of them.

Fixes PR22754 (although, we should also turn off use of vector types at -O0).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233749 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 20:35:26 +00:00
Sanjay Patel
1b10376319 [X86, AVX] fix zero-extending integer operand load patterns to use integer instructions
This is a follow-on to r233704 and another partial fix for PR22685:
https://llvm.org/bugs/show_bug.cgi?id=22685



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233724 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 18:43:43 +00:00
Lang Hames
89ddc1b326 [Orc][MCJIT] Remove the small code model regression tests.
These regression tests are supposed to test small code model support, but have
been XFAIL'd because we don't have an in-tree memory manager that can guarantee
a small-code-model compatible memory layout. Unfortunately, they can
occasionally pass if they get lucky with memory allocation, causing unexpected
passes on the bots. That's not very helpful.

I'm going to remove these until we have the infrastructure (small-code-model
compatible memory manager) to run them properly.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233722 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 18:19:25 +00:00
Tim Northover
5b8131701d AArch64: fix v8.1 sqrdmlah tests on Darwin platforms
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233709 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 16:41:38 +00:00
Sanjay Patel
7ea151449d [X86, AVX] try to lowerVectorShuffleAsElementInsertion() for all 256-bit vector sub-types
I suggested this change in D7898 (http://llvm.org/viewvc/llvm-project?view=revision&revision=231354)

It improves the v4i64 case although not optimally. This AVX codegen:

  vmovq {{.*#+}} xmm0 = mem[0],zero
  vxorpd %ymm1, %ymm1, %ymm1
  vblendpd {{.*#+}} ymm0 = ymm0[0],ymm1[1,2,3]

Becomes:

  vmovsd {{.*#+}} xmm0 = mem[0],zero

Unfortunately, this doesn't completely solve PR22685. There are still at least 2 problems under here:

    We're not handling v32i8 / v16i16.
    We're not getting the FP / int domains right for instruction selection.

But since this patch alone appears to do no harm, reduces code duplication, and helps v4i64, 
I'm submitting this patch ahead of fixing the above.

Differential Revision: http://reviews.llvm.org/D8341



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233704 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 16:32:11 +00:00
Krzysztof Parzyszek
4654bc762e Expand MUX instructions early on Hexagon
This time with all files included.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233696 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 13:35:12 +00:00
Krzysztof Parzyszek
b7c19b3cc9 Revert 233694. Weak SVN-fu.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233695 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 13:32:32 +00:00
Krzysztof Parzyszek
af4ad2d843 Expand MUX instructions early on Hexagon
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233694 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 13:29:17 +00:00
Vladimir Sukharev
e99524cf52 [AArch64] Add v8.1a "Rounding Double Multiply Add/Subtract" extension
Reviewers: t.p.northover, jmolloy

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8502


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233693 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 13:15:48 +00:00
Ulrich Weigand
cb1b3ad4e1 [SystemZ] Support RISBGN instruction on zEC12
So far, we do not yet support any instruction specific to zEC12.
Most of the facilities added with zEC12 are indeed not very useful
to compiler code generation, but there is one exception: the
miscellaneous-extensions facility provides the RISBGN instruction,
which is a variant of RISBG that does not set the condition code.

Add support for this facility, MC support for RISBGN, and CodeGen
support for prefering RISBGN over RISBG on zEC12, unless we can
actually make use of the condition code set by RISBG.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233690 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 12:58:17 +00:00
Ulrich Weigand
ee84973420 [SystemZ] Use POPCNT instruction on z196
We already exploit a number of instructions specific to z196,
but not yet POPCNT.  Add support for the population-count
facility, MC support for the POPCNT instruction, CodeGen
support for using POPCNT, and implement the getPopcntSupport
TargetTransformInfo hook.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233689 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 12:56:33 +00:00
Ulrich Weigand
64aa9d8b4c [SystemZ] Provide basic TargetTransformInfo implementation
This hooks up the TargetTransformInfo machinery for SystemZ,
and provides an implementation of getIntImmCost.

In addition, the patch adds the isLegalICmpImmediate and
isLegalAddImmediate TargetLowering overrides, and updates
a couple of test cases where we now generate slightly
better code.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233688 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 12:52:27 +00:00
Rafael Espindola
378981499a Fix the operand encoding in the test instruction.
Fixes pr22995.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233686 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 12:31:55 +00:00
James Molloy
369ee1b1f4 [SDAG] Move TRUNCATE splitting logic into a helper, and use
it more liberally.

SplitVecOp_TRUNCATE has logic for recursively splitting oversize vectors
that need more than one round of splitting to become legal. There are many
other ISD nodes that could benefit from this logic, so factor it out and
use it for FP_TO_UINT,FP_TO_SINT,SINT_TO_FP,UINT_TO_FP and FTRUNC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233681 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 10:20:58 +00:00
Ahmed Bougacha
18128bd376 [X86] Generate MOVNT for all vector types.
We used to miss non-Q YMM integer vectors, and, non-Q/D XMM integer
vectors.
While there, change the v4i32 patterns to prefer MOVNTDQ.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233668 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 03:16:51 +00:00
Duncan P. N. Exon Smith
4e5fdbfc61 tools: Unify how verifyModule() is called
Unify the error messages for the various tools when `verifyModule()`
fails on an input module.  The "brave new way" is:

    lltool: path/to/input.ll: error: input module is broken!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233667 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 03:07:23 +00:00
Alexei Starovoitov
8ffc5ca532 [bpf] mark mov instructions as ReMaterializable
loading immediate into register is cheap, so take advantage of remat.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233666 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 02:49:58 +00:00
Duncan P. N. Exon Smith
c0bf4a0671 Verifier: Move more debug info checks away from Verify()
Most of these checks were already in the `Verifier` so this is more of a
cleanup.  Now almost everything is over there.

Now that require a `name:` for `MDGlobalVariable`, add a check in
`LLParser` for it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233657 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 01:28:22 +00:00
Duncan P. N. Exon Smith
2f5cbb5947 Verifier: Move checks over from DIDescriptor::Verify()
Move over some more checks from `DIDescriptor::Verify()`, and change
`LLParser` to require non-null `file:` fields in compile units.

I've ignored the comment in test/Assembler/metadata-null-operands.ll
since I disagree with it.  At the time that test was written (r229960),
the debug info verifier wasn't on by default, so my comment there is in
the context of not expecting the verifier to be useful.  It is now, and
besides that, since r233394 we can check when parsing textual IR whether
an operand is null that shouldn't be.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233654 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 00:47:15 +00:00
Quentin Colombet
9e5f04d219 [AArch64] Fix poor codegen for add immediate.
We used to match the register variant before the immediate when the register
argument could be implicitly zero-extended.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233653 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-31 00:31:13 +00:00
David Majnemer
0a8ff297ad [WinEH] Run cleanup handlers when an exception is thrown
Generate tables in the .xdata section representing what actions to take
when an exception is thrown.  This currently fills in state for
cleanups, catch handlers are still unfinished.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233636 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 22:58:10 +00:00
Juergen Ributzka
1c8595529b Transfer implicit operands when expanding the RET_ReallyLR pseudo instruction.
When we expand the RET_ReallyLR pseudo instruction we also need to transfer the
implicit operands.

The return register is an implicit operand and without it the liveness
calculation generates an incorrect live-out set for the patchpoint.

This fixes rdar://problem/19068476.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233635 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 22:45:56 +00:00
Alexei Starovoitov
5ca9ec70fd [bpf] add support for bswap instructions
BPF has cpu_to_be and cpu_to_le instructions.
For now assume little endian and generate cpu_to_be for ISD::BSWAP.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233620 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 22:40:40 +00:00
Peter Collingbourne
07ee8d2fc1 MC: For variable symbols, maintain MCSymbol::Section as a cache.
This fixes the visibility of symbols in certain edge cases involving aliases
with multiple levels of indirection.

Fixes PR19582.

Differential Revision: http://reviews.llvm.org/D8586

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233595 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 20:41:21 +00:00
Paul Robinson
103d622517 Verify 'optnone' can run DAG combiner when appropriate.
Adds a test to verify the behavior that r233153 restored: 'optnone'
does not spuriously disable the DAG combiner, and in fact there are
cases where the DAG combiner must run (even at -O0 or 'optnone') in
order for codegen to succeed.

Differential Revision: http://reviews.llvm.org/D8614


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233584 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 19:37:44 +00:00
Justin Holewinski
e6d6461067 [NVPTX] Associate a minimum PTX version for each SM architecture
When a new SM architecture is introduced, it is only supported by the
current PTX version and later.  Make sure we are using at least the
minimum PTX version for the target architecture.

This also removes support for PTX ISA < 3.2.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233583 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 19:30:55 +00:00
Justin Holewinski
d85053fc3f [NVPTX] Add options for PTX 4.1/4.2 and SM 3.2/3.7/5.2/5.3
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233575 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 18:12:50 +00:00
Duncan P. N. Exon Smith
7380257f0e Verifier: Add operand checks for remaining debug info
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233565 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 17:21:38 +00:00
Duncan P. N. Exon Smith
d3ec0ca17e Verifier: Add operand checks for MDLexicalBlock
Add operand checks for `MDLexicalBlock` and `MDLexicalBlockFile`.  Like
`MDLocalVariable` and `MDLocation`, these nodes always require a scope.

There was no test bitrot to fix here (just updated the serialization
tests in test/Assembler/mdlexicalblock.ll).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233561 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 16:37:48 +00:00
Duncan P. N. Exon Smith
0c251f74ef DebugInfo: Rename some testcases
Momentarily (but never in tree), the `scope:` field was called
`parent:`.  Apparently a few testcases were left behind with "parent" in
the name, so rename them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233560 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 16:21:28 +00:00
Simon Pilgrim
d8f2918479 [X86] Ensure integer domain on scalar i64 load/store stack folding tests. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233553 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 15:25:51 +00:00
Ulrich Weigand
5738b77176 [SystemZ] Fix LLVM crash on unoptimized code
Compiling the following function with -O0 would crash, since LLVM would
hit an assertion in getTestUnderMaskCond:

  int test(unsigned long x)
  {
    return x >= 0 && x <= 15;
  }

Fixed by detecting the case in the caller of getTestUnderMaskCond.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233541 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 13:46:59 +00:00
Daniel Sanders
35efeb5e16 [mips] Support 9-bit offsets for the 'R' inline assembly memory constraint.
Summary:
The 'R' constraint is actually supposed to be much more complicated than
this and is defined in terms of whether it will cause macro expansion in
the assembler. 'R' is getting less useful due to architecture changes and
ought to be replaced by other constraints. We therefore implement 9-bit
offsets which will work for all subtargets and all instructions.

Reviewers: vkalintiris

Reviewed By: vkalintiris

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8440


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233537 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 13:27:25 +00:00
Daniel Jasper
a4b389c125 Revert "[SCEV] Look at backedge dominating conditions."
This leads to terribly slow compile times under MSAN. More discussion
on the commit thread of r233447.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233529 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 09:30:02 +00:00
Elena Demikhovsky
10e73aeede AVX-512: blank lines, duplicated tests, no functional changes
see comments http://reviews.llvm.org/D6835


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233528 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 09:29:28 +00:00
Elena Demikhovsky
f5f12f1e92 AVX-512: added intrinsics for VPAND, VPOR and VPXOR
by Asaf Badouh (asaf.badouh@intel.com)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233525 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 08:30:34 +00:00
Benjamin Kramer
155328790b [inline asm] Don't reject duplicated matching constraints
They're harmless and it's easy to generate them from clang, leading to
a crash in LLVM. Found by afl-fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233500 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-29 20:33:07 +00:00
Akira Hatanaka
0de206d8d6 [Objdump] Pass the correct subtarget to printInst.
This fixes a bug I introduced in r233411.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233484 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-28 20:44:05 +00:00
Hal Finkel
2eaf50f5fb [PowerPC] Add asm parser support for bitmask forms of rotate-and-mask instructions
The asm syntax for the 32-bit rotate-and-mask instructions can take a 32-bit
bitmask instead of an (mb, me) pair. This syntax is not specified in the Power
ISA manual, but is accepted by GNU as, and is documented in IBM's Assembler
Language Reference. The GNU Multiple Precision Arithmetic Library (gmp)
contains assembly that uses this syntax.

To implement this, I moved the isRunOfOnes utility function from
PPCISelDAGToDAG.cpp to PPCMCTargetDesc.h.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233483 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-28 19:42:41 +00:00
Hal Finkel
8360002904 [ConstantFold] Don't fold ppc_fp128 <-> int bitcasts
PPC_FP128 is really the sum of two consecutive doubles, where the first double
is always stored first in memory, regardless of the target endianness. The
memory layout of i128, however, depends on the target endianness, and so we
can't fold this without target endianness information. As a result, we must not
do this folding in lib/IR/ConstantFold.cpp (it could be done instead in
Analysis/ConstantFolding.cpp, but that's not done now).

Fixes PR23026.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233481 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-28 16:44:57 +00:00
Duncan P. N. Exon Smith
cefca10039 Verifier: Allow subroutine types to have no type array
Loosen one check from r233446: as long as `DIBuilder` requires a
non-null type for every subprogram, we should allow a null type array.
Also add tests for the rest of `MDSubroutineType`, which were somehow
missing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233468 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-28 02:43:53 +00:00
Duncan P. N. Exon Smith
d397a52305 DebugInfo: Fix testcases with invalid MDSubprogram nodes
Fix testcases that don't pass the verifier after a WIP patch to check
`MDSubprogram` operands more effectively.  I found the following issues:

  - When `isDefinition: false`, the `variables:` field might point at
    `!{i32 786468}`, or at a tuple that pointed at an empty tuple with
    the comment "previously: invalid DW_TAG_base_type" (I vaguely recall
    adding those comments during an upgrade script).  In these cases, I
    just dropped the array.
  - The `variables:` field might point at something like `!{!{!8}}`,
    where `!8` was an `MDLocation`.  I removed the extra layer of
    indirection.
  - Invalid `type:` (not an `MDSubroutineType`).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233466 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-28 02:26:45 +00:00
Akira Hatanaka
57e9efecb0 [ARM] Enable changing instprinter's behavior based on the per-function
subtarget.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233451 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-27 23:41:42 +00:00
Sanjoy Das
e464bbfb5a [SCEV] Look at backedge dominating conditions.
Summary:
This change teaches ScalarEvolution::isLoopBackedgeGuardedByCond to look
at edges within the loop body that dominate the latch.  We don't do an
exhaustive search for all possible edges, but only a quick walk up the
dom tree.

Reviewers: atrick, hfinkel

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8627

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233447 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-27 23:18:08 +00:00