5050 Commits

Author SHA1 Message Date
Krzysztof Parzyszek
fcc330abfe Allow memory intrinsics to be tail calls
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234764 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-13 17:16:45 +00:00
Benjamin Kramer
829e013107 Remove empty non-virtual destructors or mark them =default when non-public
These add no value but can make a class non-trivially copyable. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234688 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-11 15:32:26 +00:00
Alexander Kornienko
c16fc54851 Use 'override/final' instead of 'virtual' for overridden methods
The patch is generated using clang-tidy misc-use-override check.

This command was used:

  tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py \
    -checks='-*,misc-use-override' -header-filter='llvm|clang' \
    -j=32 -fix -format

http://reviews.llvm.org/D8925



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234679 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-11 02:11:45 +00:00
Jingyue Wu
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
David Majnemer
d480d308b0 [WinEHPrepare] Don't rely on the order of IR
The IPToState table must be emitted after we have generated labels for
all functions in the table.  Don't rely on the order of the list of
globals.  Instead, utilize WinEHFuncInfo to tell us how many catch
handlers we expect to outline.  Once we know we've visited all the catch
handlers, emit the cppxdata.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234566 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-10 04:56:17 +00:00
Sanjay Patel
bf9be6b7e2 move helper function closer to use; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234344 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-07 19:13:06 +00:00
Rafael Espindola
1252bb4b17 Clear the stub map in getSortedStubs.
This makes sure they are only output once (and frees a bit of memory).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234313 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-07 12:59:28 +00:00
Duncan P. N. Exon Smith
0477045c32 CodeGen: Stop using DIDescriptor::is*() and auto-casting
Same as r234255, but for lib/CodeGen and lib/Target.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234258 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-06 23:27:40 +00:00
Duncan P. N. Exon Smith
1ea24954c6 DebugInfo: Remove DIDescriptor::Verify()
Remove `DIDescriptor::Verify()` and the `Verify()`s from subclasses.
They had already been gutted, and just did an `isa<>` check.

In a couple of cases I've temporarily dropped the check entirely, but
subsequent commits are going to disallow conversions to the
`DIDescriptor`s directly from `MDNode`, so the checks will come back in
another form soon enough.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234201 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-06 19:49:39 +00:00
Sanjay Patel
166e26c295 remove function/variable names from comments; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234107 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-04 21:06:39 +00:00
Rafael Espindola
903f4a2051 Implement unique sections with an unique ID.
This allows the compiler/assembly programmer to switch back to a
section. This in turn fixes the bootstrap failure on powerpc (tested
on gcc110) without changing the ppc codegen at all.

I will try to cleanup the various getELFSection overloads in a  followup patch.
Just using a default argument now would lead to ambiguities.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234099 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-04 18:02:01 +00:00
David Majnemer
45221a75fb [WinEH] Fill out CatchHigh in the TryBlockMap
Now all fields in the WinEH xdata have been filled out.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234067 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-03 23:37:34 +00:00
David Majnemer
8431785c5e [WinEH] Fill out .xdata for catch objects
This add support for catching an exception such that an exception object
available to the catch handler will be initialized by the runtime.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234062 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-03 22:49:05 +00:00
David Majnemer
f89ce9a09d [WinEH] Sink UnwindHelp completely out of IR
We don't need to represent UnwindHelp in IR.  Instead, we can use the
knowledge that we are emitting the parent function to decide if we
should create the UnwindHelp stack object.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234061 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-03 22:32:26 +00:00
Andrew Kaylor
675e22e7ad [WinEH] Handle nested landing pads in outlined catch handlers
Differential Revision: http://reviews.llvm.org/D8596



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234041 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-03 19:37:50 +00:00
Duncan P. N. Exon Smith
f4f021c0a4 CodeGen: Assert that inlined-at locations agree
As a follow-up to r234021, assert that a debug info intrinsic variable's
`MDLocalVariable::getInlinedAt()` always matches the
`MDLocation::getInlinedAt()` of its `!dbg` attachment.

The goal here is to get rid of `MDLocalVariable::getInlinedAt()`
entirely (PR22778), but I'll let these assertions bake for a while
first.

If you have an out-of-tree backend that just broke, you're probably
attaching the wrong `DebugLoc` to a `DBG_VALUE` instruction.  The one
you want is the location that was attached to the corresponding
`@llvm.dbg.declare` or `@llvm.dbg.value` call that you started with.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234038 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-03 19:20:26 +00:00
Matthias Braun
b2e4ca21f4 MachineRegisterInfo: Make it clear that hints are for vregs
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233986 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-03 00:18:33 +00:00
Philip Reames
57bea4161b [gcroot] Remove unused items from an enum
These two were never implemented for gcroot, so there's no point in keeping them around now.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233892 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-02 05:02:16 +00:00
Matthias Braun
a8d688454d Remove declarations for nonexistent methods
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233841 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-01 21:16:02 +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
497110d1b0 DebugLoc: Remove getFromDILexicalBlock()
The only user of `DebugLoc::getFromDILexicalBlock()` was creating a new
`MDLocation` as convenient API for passing an `MDScope`.  Stop doing
that, and remove the API.  If in the future we actually *want* to create
new DebugLocs, calling `MDLexicalBlock::get()` makes more sense.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233643 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 23:47:26 +00:00
Duncan P. N. Exon Smith
62e3e389b9 LexicalScopes: Use debug info hierarchy pervasively
Pervasively use the types provided by the debug info hierarchy rather
than `MDNode` in `LexicalScopes`.

I noticed (again, I guess, based on comments in the implementation?)
that `DILexicalBlockFile::getScope()` returns something different from
`DILexicalBlockFile::getContext()`.  I created a local helper for
getting the same logic from `MDLexicalBlockFile` called
`getScopeOfScope()`.  I still don't really understand it, but I've added
some FIXMEs and I'll come back to it (I suspect the way we encode these
objects isn't really ideal).

Note that my previous commit r233610 accidentally changed behaviour in
`findLexicalScope()` -- it transitioned from a call to
`DILexicalBlockFile::getScope()` to `MDLexicalBlockFile::getScope()`
(sounds right, doesn't it?) -- so I've fixed that as a drive-by.  No
tests failed with my error, so it looks like we're missing some coverage
here... when I come back to understand the logic, I'll see if I can add
some.

Other than the fix to `findLexicalScope()`, no functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233640 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 23:21:21 +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
Duncan P. N. Exon Smith
35ff67e333 LexicalScopes: Use MDLocation directly instead of DebugLoc
There's no benefit to using `DebugLoc` here.  Moreover, this will let a
follow-up commit work with `MDScope` directly instead of `DebugLoc`.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233610 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 21:54:46 +00:00
Simon Pilgrim
eb32048f80 [DAGCombiner] Add support for TRUNCATE + FP_EXTEND vector constant folding
This patch adds supports for the vector constant folding of TRUNCATE and FP_EXTEND instructions and tidies up the SINT_TO_FP and UINT_TO_FP instructions to match.

It also moves the vector constant folding for the FNEG and FABS instructions to use the DAG.getNode() functionality like the other unary instructions.

Differential Revision: http://reviews.llvm.org/D8593

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233224 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-25 22:30:31 +00:00
Benjamin Kramer
1989d62bf1 Internalize the StackMapLiveness pass.
No need to have its own header when it's not used anywhere. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233072 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-24 13:20:54 +00:00
Eric Christopher
ba617ac1cc Change getISAEncoding to use the target triple to determine
thumb-ness similar to the rest of the Module level asm printing
infrastructure as debug info finalization happens after the function
may be missing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232875 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-21 03:13:01 +00:00
Eric Christopher
aaca69b339 Remove dead calls and function arguments dealing with TRI in StackMaps.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232847 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-20 21:05:18 +00:00
Eric Christopher
aa6604c351 Rewrite StackMap location handling to pre-compute the dwarf register
numbers before emission.

This removes a dependency on being able to access TRI at the module
level and is similar to the DwarfExpression handling. I've modified
the debug support into print/dump routines that'll do the same dumping
but is now callable anywhere and if TRI isn't available will go ahead
and just print out raw register numbers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232821 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-20 16:03:42 +00:00
Matthias Braun
5101c89f13 Do not track subregister liveness when it brings no benefits
Some subregisters are only to indicate different access sizes, while not
providing any way to actually divide the register up into multiple
disjunct parts. Avoid tracking subregister liveness in these cases as it
is not beneficial.

Differential Revision: http://reviews.llvm.org/D8429

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232695 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-19 00:21:58 +00:00
NAKAMURA Takumi
1484f91953 Split comma-separated \param(s). [-Wdocumentation]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232584 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-18 02:09:25 +00:00
David Majnemer
7605cdd6e4 COFF: Let globals with private linkage reside in their own section
COFF COMDATs (for selection kinds other than 'select any') require at
least one non-section symbol in the symbol table.
Satisfy this by morally enhancing the linkage from private to internal.

Differential Revision: http://reviews.llvm.org/D8394

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232570 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-17 23:54:51 +00:00
David Majnemer
76d3a99d10 Revert "COFF: Let globals with private linkage reside in their own section"
This reverts commit r232539.  This was committed accidently.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232543 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-17 20:41:11 +00:00
David Majnemer
6526150f82 COFF: Let globals with private linkage reside in their own section
Summary:
COFF COMDATs (for selection kinds other than 'select any') require at
least one non-section symbol in the symbol table.
Satisfy this by morally enhancing the linkage from private to internal.

Reviewers: rafael

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8374

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232539 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-17 20:39:25 +00:00
Rafael Espindola
b415e6b2f2 Centralize the handling of unique ids for temporary labels.
Before this patch code wanting to create temporary labels for a given entity
(function, cu, exception range, etc) had to keep its own counter to have stable
symbol names.

createTempSymbol would still add a suffix to make sure a new symbol was always
returned, but it kept a single counter. Because of that, if we were to use
just createTempSymbol("cu_begin"), the label could change from cu_begin42 to
cu_begin43 because some other code started using temporary labels.

Simplify this by just keeping one counter per prefix and removing the various
specialized counters.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232535 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-17 20:07:06 +00:00
Michael Zolotukhin
6e046d3810 TTI: Honour cost model for estimating cost of vector-intrinsic and calls.
Review: http://reviews.llvm.org/D8096

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232528 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-17 19:37:28 +00:00
Michael Zolotukhin
51b4d85c62 TTI: Add getCallInstrCost.
Review: http://reviews.llvm.org/D8094

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232524 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-17 19:26:23 +00:00
Rafael Espindola
0bea785427 Remove the error prone GetTempSymbol API.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232487 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-17 15:02:17 +00:00
Rafael Espindola
b80d90e9d0 Make EmitFunctionHeader a private helper.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232481 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-17 14:38:30 +00:00
Rafael Espindola
a480f88b3c Move the EH symbol to the asm printer and use it for the SJLJ case too.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232475 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-17 13:57:48 +00:00
Duncan P. N. Exon Smith
3d5527fb43 IR: Take advantage of -verify checks for MDExpression
Now that we check `MDExpression` during `-verify` (r232299), make
the `DIExpression` wrapper more strict:

  - remove redundant checks in `DebugInfoVerifier`,
  - overload `get()` to `cast_or_null<MDExpression>` (superseding
    `getRaw()`),
  - stop checking for null in any accessor, and
  - remove `DIExpression::Verify()` entirely in favour of
    `MDExpression::isValid()`.

There is still some logic in this class, mostly to do with high-level
iterators; I'll defer cleaning up those until the rest of the wrappers
are similarly strict.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232412 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-16 21:03:55 +00:00
David Blaikie
7610ba7d24 Fix uses of reserved identifiers starting with an underscore followed by an uppercase letter
This covers essentially all of llvm's headers and libs. One or two weird
cases I wasn't sure were worth/appropriate to fix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232394 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-16 18:06:57 +00:00
Akira Hatanaka
ed7120e7fd [AsmPrinter] Use the per-function subtarget to emit inline asm instructions that
are not at the file level.

Previously, the default subtarget created from the target triple was used to
emit inline asm instructions. Compilation would fail in cases where the feature
bits necessary to assemble an inline asm instruction in a function weren't set.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232392 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-16 18:02:16 +00:00
Daniel Sanders
547ba56bd0 Recommit r232027 with PR22883 fixed: Add infrastructure for support of multiple memory constraints.
The operand flag word for ISD::INLINEASM nodes now contains a 15-bit
memory constraint ID when the operand kind is Kind_Mem. This constraint
ID is a numeric equivalent to the constraint code string and is converted
with a target specific hook in TargetLowering.

This patch maps all memory constraints to InlineAsm::Constraint_m so there
is no functional change at this point. It just proves that using these
previously unused bits in the encoding of the flag word doesn't break
anything.

The next patch will make each target preserve the current mapping of
everything to Constraint_m for itself while changing the target independent
implementation of the hook to return Constraint_Unknown appropriately. Each
target will then be adapted in separate patches to use appropriate
Constraint_* values.

PR22883 was caused the matching operands copying the whole of the operand flags
for the matched operand. This included the constraint id which needed to be
replaced with the operand number. This has been fixed with a conversion
function. Following on from this, matching operands also used the operand
number as the constraint id. This has been fixed by looking up the matched
operand and taking it from there. 



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232165 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-13 12:45:09 +00:00
Hal Finkel
8faeecead0 Revert "r232027 - Add infrastructure for support of multiple memory constraints"
This (r232027) has caused PR22883; so it seems those bits might be used by
something else after all. Reverting until we can figure out what else to do.

Original commit message:

The operand flag word for ISD::INLINEASM nodes now contains a 15-bit
memory constraint ID when the operand kind is Kind_Mem. This constraint
ID is a numeric equivalent to the constraint code string and is converted
with a target specific hook in TargetLowering.

This patch maps all memory constraints to InlineAsm::Constraint_m so there
is no functional change at this point. It just proves that using these
previously unused bits in the encoding of the flag word doesn't break anything.

The next patch will make each target preserve the current mapping of
everything to Constraint_m for itself while changing the target independent
implementation of the hook to return Constraint_Unknown appropriately. Each
target will then be adapted in separate patches to use appropriate Constraint_*
values.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232093 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-12 20:09:39 +00:00
Daniel Sanders
67f6425792 Add infrastructure for support of multiple memory constraints.
Summary:
The operand flag word for ISD::INLINEASM nodes now contains a 15-bit
memory constraint ID when the operand kind is Kind_Mem. This constraint
ID is a numeric equivalent to the constraint code string and is converted
with a target specific hook in TargetLowering.

This patch maps all memory constraints to InlineAsm::Constraint_m so there
is no functional change at this point. It just proves that using these
previously unused bits in the encoding of the flag word doesn't break anything.

The next patch will make each target preserve the current mapping of
everything to Constraint_m for itself while changing the target independent
implementation of the hook to return Constraint_Unknown appropriately. Each
target will then be adapted in separate patches to use appropriate Constraint_*
values.

Reviewers: hfinkel

Reviewed By: hfinkel

Subscribers: hfinkel, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D8171


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232027 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-12 11:00:48 +00:00
Rafael Espindola
0c78583bf6 Put jump tables in unique sections on COFF.
If a function is going in an unique section (because of -ffunction-sections
for example), putting a jump table in .rodata will keep .rodata alive and
that will keep alive any other function that also has a jump table.

Instead, put the jump table in a unique section that is associated with the
function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231961 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-11 19:58:37 +00:00
Bruno Cardoso Lopes
84e6358ea0 [AsmPrinter][TLOF] Reintroduce AArch64 test
Follow up from r231505.

Fix the non-determinism by using a MapVector and reintroduce the AArch64
testcase. Defer deleting the got candidates up to the end and remove
them in a bulk, avoiding linear time removal of each element.

Thanks to Renato Golin for trying it out on other platforms.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231830 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-10 20:05:23 +00:00
Rafael Espindola
0f4df6dc6f Store an optional section start label in MCSection.
This makes code that uses section relative expressions (debug info) simpler and
less brittle.

This is still a bit awkward as the symbol is created late and has to be
stored in a mutable field.

I will move the symbol creation earlier in the next patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231802 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-10 16:58:10 +00:00
Chad Rosier
e891f49ad5 [BranchFolding] Remove MMOs during tail merge to preserve dependencies.
When tail merging it may be necessary to remove MMOs from memory operations to
ensures later passes (e.g., MI sched) conservatively compute dependencies.
Currently, we only remove the MMO from the common tail if the MMO doesn't match
with the relative instruction in the non-common tail(s).

A more robust solution would be to add multiple MMOs from the duplicate MIs to
the new MI. Currently ScheduleDAGInstrs.cpp ignores all MMOs on instructions
with multiple MMOs, so this solution is equivalent for the time being.

No test case included as this is incredibly difficult to reproduce.

Patch was a collaborative effort between Ana Pazos and myself.
Phabricator: http://reviews.llvm.org/D7769

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231799 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-10 16:22:52 +00:00