Clarify the description of the noalias attribute

The previous description of the noalias attribute did not accurately specify
the implemented semantics, and the terminology used differed unnecessarily
from that used by the C specification to define the semantics of restrict. For
the argument attribute, the semantics can be precisely specified in terms of
objects accessed through pointers based on the arguments, and this is now what
is done.

Saying that the semantics are 'slightly weaker' than that provided by C99
restrict is not really useful without further elaboration, so that has been
removed from the sentence.

noalias on a return value is really used to mean that the function is
malloc-like (and, in fact, we use this attribute to represent
__attribute__((malloc)) in Clang), and this is a stronger guarantee than that
provided by restrict (because it is a property of the pointed-to memory region,
not just a guarantee on object access). Clarifying this is relevant to fixing
(and was motivated by the discussion on) PR21556.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222497 91177308-0d34-0410-b5e6-96231b3b80d8
SROA: The alloca type isn't a candidate promotion type for vectors

The alloca's type is irrelevant, only those types which are used in a
load or store of the exact size of the slice should be considered.

This manifested as an assertion failure when we compared the various
types: we had a size mismatch.

This fixes PR21480.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222499 91177308-0d34-0410-b5e6-96231b3b80d8
This Reassociate change unintentionally slipped in r222499

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222500 91177308-0d34-0410-b5e6-96231b3b80d8
Add accessor marcos to ConstantPlaceHolder, similar to those in the base class.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222502 91177308-0d34-0410-b5e6-96231b3b80d8
[PPC] Use SeparateConstOffsetFromGEP

This mirrors r222331, which enabled SeparateConstOffsetFromGEP on AArch64, in
the PowerPC backend. Yields, on a POWER7 machine, a 30% speedup on
SingleSource/Benchmarks/Shootout/nestedloop (this might just be from LICM,
there is a store moved out of the inner loop) and a potential speedup on
MultiSource/Benchmarks/mediabench/mpeg2/mpeg2dec/mpeg2decode. Regardless, it
makes some code look cleaner, and synchronizing the backends in this regard
seems like a generally good thing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222504 91177308-0d34-0410-b5e6-96231b3b80d8
Fix a silly bug in StreamingMemoryObject.cpp.

The logic for detecting EOF was wrong and would fail if we ever requested
more than 16k past the last read position.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222505 91177308-0d34-0410-b5e6-96231b3b80d8
Add extra new line and remove some trailing whitespace from tablegen RegisterInfo output file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222508 91177308-0d34-0410-b5e6-96231b3b80d8
Remove a bunch of unnecessary typecasts to 'const TargetRegisterClass *'

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222509 91177308-0d34-0410-b5e6-96231b3b80d8
DAGCombiner: Allow the DAGCombiner to combine multiple FDIVs with the same divisor info FMULs by the reciprocal.
E.g., ( a / D; b / D ) -> ( recip = 1.0 / D; a * recip; b * recip)

A hook is added to allow the target to control whether it needs to do such combine.

Reviewed in http://reviews.llvm.org/D6334


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222510 91177308-0d34-0410-b5e6-96231b3b80d8
Add LLVMScalarOpts to LLVMPowerPCCodeGen.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222516 91177308-0d34-0410-b5e6-96231b3b80d8
Merge branch 'master', remote-tracking branch 'trunk/master'