[InstCombine] re-commit r218721 icmp-select-icmp optimization

Takes care of the assert that caused build fails.
Rather than asserting the code checks now that the definition
and use are in the same block, and does not attempt
to optimize when that is not the case.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219175 91177308-0d34-0410-b5e6-96231b3b80d8
gold plugin: Remap function arguments when creating a replacement function.

When creating an internal function replacement for use in an alias we were
not remapping the argument uses in the instructions to point to the new
arguments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219177 91177308-0d34-0410-b5e6-96231b3b80d8
gold plugin: create internal replacement with original linkage first.

The call to copyAttributesFrom will copy the visibility, which might assert
if it were to produce something invalid like "internal hidden". We avoid it
by first creating the replacement with the original linkage and then setting
it to internal affter the call to copyAttributesFrom.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219184 91177308-0d34-0410-b5e6-96231b3b80d8
[FastISel][AArch64] Fix "Fold sign-/zero-extends into the load instruction."

This commit fixes an issue with sign-/zero-extending loads that was discovered
by Richard Barton.

We use now the correct load instructions for sign-extending loads to 64bit. Also
updated and added more unit tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219185 91177308-0d34-0410-b5e6-96231b3b80d8
[FastISel][AArch64] Teach the address computation to also fold sub instructions.

Tiny enhancement to the address computation code to also fold sub instructions
if the rhs is constant and can be folded into the offset.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219186 91177308-0d34-0410-b5e6-96231b3b80d8
[FastISel][AArch64] Teach the address computation code to also fold sign-/zero-extends.

The code already folds sign-/zero-extends, but only if they are arguments to
mul and shift instructions. This extends the code to also fold them when they
are direct inputs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219187 91177308-0d34-0410-b5e6-96231b3b80d8
gold plugin: Handle gold selecting a linkonce GV when a weak is present.

The plugin API doesn't have the notion of linkonce, only weak. It is up to the
plugin to figure out if a symbol used only for the symbol table can be dropped.
In particular, it has to avoid dropping a linkonce_odr selected by gold if there
is also a weak_odr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219188 91177308-0d34-0410-b5e6-96231b3b80d8
Support: Don't call close again if we get EINTR

Most Unix-like operating systems guarantee that the file descriptor is
closed after a call to close(2), even if close comes back with EINTR.
For these systems, calling close _again_ will either do nothing or close
some other file descriptor open(2)'d by another thread. (Linux)

However, some operating systems do not have this behavior.  They require
at least another call to close(2) before guaranteeing that the
descriptor is closed. (HP-UX)

And some operating systems have an unpredictable blend of the two
behaviors! (xnu)

Avoid this disaster by blocking all signals before we call close(2).
This ensures that a signal will not be delivered to the thread and
close(2) will not give us back EINTR.  We restore the signal mask once
the operation is done.

N.B. This isn't a problem on Windows, it doesn't have a notion of EINTR
because signals always get delivered to dedicated signal handling
threads.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219189 91177308-0d34-0410-b5e6-96231b3b80d8
Attempt to calm down buildbots

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219190 91177308-0d34-0410-b5e6-96231b3b80d8
GlobalDCE: Don't drop any COMDAT members

If we require a single member of a comdat, require all of the other
members as well.

This fixes PR20981.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219191 91177308-0d34-0410-b5e6-96231b3b80d8
Fix filename in header and use C++ version of the C header files.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219192 91177308-0d34-0410-b5e6-96231b3b80d8
Formatting fixes. Most putting 'else' on the same line as the preceding curly brace.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219193 91177308-0d34-0410-b5e6-96231b3b80d8
[X86] Fix a bug where the disassembler was ignoring the VEX.W bit in 32-bit mode for certain instructions it shouldn't.

Unfortunately, this isn't easy to fix since there's no simple way to figure out from the disassembler tables whether the W-bit is being used to select a 64-bit GPR or if its a required part of the opcode. The fix implemented here just looks for "64" in the instruction name and ignores the W-bit in 32-bit mode if its present.

Fixes PR21169.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219194 91177308-0d34-0410-b5e6-96231b3b80d8
Merge branch 'master', remote-tracking branch 'trunk/master'