Decompose GVN::processNonLocalLoad() (about 400 LOC) into smaller helper functions. No function change. 

This function consists of following steps:
   1. Collect dependent memory accesses.
   2. Analyze availability.
   3. Perform fully redundancy elimination, or 
   4. Perform PRE, depending on the availability

 Step 2, 3 and 4 are now moved to three helper routines.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181047 91177308-0d34-0410-b5e6-96231b3b80d8

[PowerPC] Add assembler parser

This adds assembler parser support to the PowerPC back end.

The parser will run for any powerpc-*-* and powerpc64-*-* triples,
but was tested only on 64-bit Linux.  The supported syntax is
intended to be compatible with the GNU assembler.

The parser does not yet support all PowerPC instructions, but
it does support anything that is generated by LLVM itself.
There is no support for testing restricted instruction sets yet,
i.e. the parser will always accept any instructions it knows,
no matter what feature flags are given.

Instruction operands will be checked for validity and errors
generated.  (Error handling in general could still be improved.)

The patch adds a number of test cases to verify instruction
and operand encodings.  The tests currently cover all instructions
from the following PowerPC ISA v2.06 Book I facilities:
Branch, Fixed-point, Floating-Point, and Vector. 
Note that a number of these instructions are not yet supported
by the back end; they are marked with FIXME.

A number of follow-on check-ins will add extra features.  When
they are all included, LLVM passes all tests (including bootstrap)
when using clang -cc1as as the system assembler.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181050 91177308-0d34-0410-b5e6-96231b3b80d8

[PowerPC] Support extended mnemonics in AsmParser

This patch adds infrastructure to support extended mnemonics in the
PowerPC assembler parser.  It adds support specifically for those
extended mnemonics that LLVM will itself generate.

The test case lists *all* extended mnemonics according to the
PowerPC ISA v2.06 Book I, but marks those not yet supported
as FIXME.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181051 91177308-0d34-0410-b5e6-96231b3b80d8

[PowerPC] Add some Book II instructions to AsmParser

This patch adds a couple of Book II instructions (isync, icbi) to the
PowerPC assembler parser.  These are needed when bootstrapping clang
with the integrated assembler forced on, because they are used in
inline asm statements in the code base.

The test case adds the full list of Book II storage control instructions,
including associated extended mnemonics.  Again, those that are not yet
supported as marked as FIXME.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181052 91177308-0d34-0410-b5e6-96231b3b80d8

[PowerPC] Parse platform-specifc variant kinds in AsmParser

This patch adds support for PowerPC platform-specific variant
kinds in MCSymbolRefExpr::getVariantKindForName, and also
adds a test case to verify they are translated to the appropriate
fixup type.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181053 91177308-0d34-0410-b5e6-96231b3b80d8

[PowerPC] Avoid using '$' in generated assembler code

PowerPC assemblers are supposed to support a stand-alone '$' symbol
as an alternative of '.' to refer to the current PC.  This does not
work in the LLVM assembler parser yet.

To avoid bootstrap failures when using the LLVM assembler as system
assembler, this patch modifies the assembler source code generated
by LLVM to avoid using '$' (and simply use '.' instead).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181054 91177308-0d34-0410-b5e6-96231b3b80d8