correct target directive handling error handling

The target specific parser should return `false' if the target AsmParser handles
the directive, and `true' if the generic parser should handle the directive.
Many of the target specific directive handlers would `return Error' which does
not follow these semantics.  This change simply changes the target specific
routines to conform to the semantis of the ParseDirective correctly.

Conformance to the semantics improves diagnostics emitted for the invalid
directives.  X86 is taken as a sample to ensure that multiple diagnostics are
not presented for a single error.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199068 91177308-0d34-0410-b5e6-96231b3b80d8
[AArch64 NEON] Add more scenarios to use perm instructions when lowering shuffle_vector

This patch covered 2 more scenarios:

1.  Two operands of shuffle_vector are the same, like
%shuffle.i = shufflevector <8 x i8> %a, <8 x i8> %a, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>

2. One of operands is undef, like
%shuffle.i = shufflevector <8 x i8> %a, <8 x i8> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>

After this patch, perm instructions will have chance to be emitted instead of lots of INS.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199069 91177308-0d34-0410-b5e6-96231b3b80d8
[AArch64 NEON] Add missing patterns for bitcast from or to v1f64

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199070 91177308-0d34-0410-b5e6-96231b3b80d8
[PM] Add an enum for describing the desired output strategy, and run
that through the interface rather than a simple bool. This should allow
starting to wire up real output to round-trip IR through opt with the
new pass manager.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199071 91177308-0d34-0410-b5e6-96231b3b80d8
[PM] Wire up support for printing assembly output from the opt command.
This lets us round-trip IR in the expected manner with the opt tool.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199075 91177308-0d34-0410-b5e6-96231b3b80d8
[CMake] Move BUG_REPORT_URL from clang to llvm.

It was too late to set BUG_REPORT_URL after configure_file(config.h).
BUG_REPORT_URL in config.h.cmake would be updated at 2nd run of cmake.
It caused many recompilations.

FYI, configure handles BUG_REPORT_URL in llvm side.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199076 91177308-0d34-0410-b5e6-96231b3b80d8
llvm/test/ExecutionEngine/MCJIT/load-object-a.ll: Put together rm(1) and mkdir(1) at the top.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199077 91177308-0d34-0410-b5e6-96231b3b80d8
[PM] Wire up support for writing bitcode with new PM.

This moves the old pass creation functionality to its own header and
updates the callers of that routine. Then it adds a new PM supporting
bitcode writer to the header file, and wires that up in the opt tool.
A test is added that round-trips code into bitcode and back out using
the new pass manager.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199078 91177308-0d34-0410-b5e6-96231b3b80d8
Re-sort #include lines again, prior to moving headers around.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199080 91177308-0d34-0410-b5e6-96231b3b80d8
[cleanup] Add a missing include exposed by resorting other includes.
Should fix the build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199081 91177308-0d34-0410-b5e6-96231b3b80d8
[cleanup] Move the Dominators.h and Verifier.h headers into the IR
directory. These passes are already defined in the IR library, and it
doesn't make any sense to have the headers in Analysis.

Long term, I think there is going to be a much better way to divide
these matters. The dominators code should be fully separated into the
abstract graph algorithm and have that put in Support where it becomes
obvious that evn Clang's CFGBlock's can use it. Then the verifier can
manually construct dominance information from the Support-driven
interface while the Analysis library can provide a pass which both
caches, reconstructs, and supports a nice update API.

But those are very long term, and so I don't want to leave the really
confusing structure until that day arrives.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199082 91177308-0d34-0410-b5e6-96231b3b80d8
[cleanup] Switch comments to use '\brief' style instead of '@brief'
style, and remove some unnecessary comments (the code is perfectly
self-documenting here). Also clang-format the function declarations as
they wrap cleanly now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199084 91177308-0d34-0410-b5e6-96231b3b80d8
[cleanup] Fix the includes in the examples for r199082.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199087 91177308-0d34-0410-b5e6-96231b3b80d8
[cleanup] Re-sort the examples #include lines with my sort_includes
script.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199089 91177308-0d34-0410-b5e6-96231b3b80d8
ReMat: fix overly cavalier attitude to sub-register indices

There are two attempted optimisations in reMaterializeTrivialDef, trying to
avoid promoting the size of a register too much when rematerializing.
Unfortunately, both appear to be flawed. First, we see if the original register
would have worked, but this is inadequate. Consider:

    v1 = SOMETHING (v1 is QQ)
    v2:Q0 = COPY v1:Q1 (v1, v2 are QQ)
    ...
    uses of v2

In this case even though v2 *could* be used directly as the output of
SOMETHING, this would set the wrong bits of the QQ register involved. The
correct rematerialization must be:

    v2:Q0_Q1 = SOMETHING (v2 promoted to QQQ)
    ...
    uses of v2:Q1_Q2

For the second optimisation, if the correct remat is "v2:idx = SOMETHING" then
we can't necessarily expect v2 itself to be valid for SOMETHING, but we do try
to hunt for a class between v1 and v2 that works. Unfortunately, this is also
wrong:

    v1 = SOMETHING (v1 is QQ)
    v2:Q0_Q1 = COPY v1 (v1 is QQ, v2 is QQQ)
    ...
    uses of v2 as a QQQ

The canonical rematerialization here is "v2:Q0_Q1 = SOMETHING". However current
logic would decide that v2 could be a QQ (no interest is taken in later uses).

This patch, therefore, always accepts the widened register class without trying
to be clever. Generally there is no penalty to this (e.g. in the common GR32 <
GR64 case, expanding the width doesn't matter because it's not like you were
going to do anything else with the high bits of a GR32 register). It can
increase register pressure in cases like the ARM VFP regs though (multiple
non-overlapping but equivalent subregisters). Hopefully this situation is rare
enough that it won't matter.

Unfortunately, no in-tree targets actually expose this as far as I can tell
(there are so few isAsCheapAsAMove instructions for it to trigger on) so I've
been unable to produce a test. It was exposed in our ARM64 SPEC tests though,
and I will be adding a test there that we should be able to contribute
soon(TM).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199091 91177308-0d34-0410-b5e6-96231b3b80d8
Docs: fix sign of division and increase equivocation on code generated.

I should have been a politician.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199092 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "ReMat: fix overly cavalier attitude to sub-register indices"

Very sorry, this was a premature patch that I still need to investigate and
finish off (for some reason beyond me at the moment it doesn't actually fix the
issue in all cases).

This reverts commit r199091.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199093 91177308-0d34-0410-b5e6-96231b3b80d8
[PM] Pull the generic graph algorithms and data structures for dominator
trees into the Support library.

These are all expressed in terms of the generic GraphTraits and CFG,
with no reliance on any concrete IR types. Putting them in support
clarifies that and makes the fact that the static analyzer in Clang uses
them much more sane. When moving the Dominators.h file into the IR
library I claimed that this was the right home for it but not something
I planned to work on. Oops.

So why am I doing this? It happens to be one step toward breaking the
requirement that IR verification can only be performed from inside of
a pass context, which completely blocks the implementation of
verification for the new pass manager infrastructure. Fixing it will
also allow removing the concept of the "preverify" step (WTF???) and
allow the verifier to cleanly flag functions which fail verification in
a way that precludes even computing dominance information. Currently,
that results in a fatal error even when you ask the verifier to not
fatally error. It's awesome like that.

The yak shaving will continue...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199095 91177308-0d34-0410-b5e6-96231b3b80d8