[PowerPC 1/4] Little-endian adjustments for VSX loads/stores

This patch addresses the inherent big-endian bias in the lxvd2x,
lxvw4x, stxvd2x, and stxvw4x instructions.  These instructions load
vector elements into registers left-to-right (with the first element
loaded into the high-order bits of the register), regardless of the
endian setting of the processor.  However, these are the only
vector memory instructions that permit unaligned storage accesses, so
we want to use them for little-endian.

To make this work, a lxvd2x or lxvw4x is replaced with an lxvd2x
followed by an xxswapd, which swaps the doublewords.  This works for
lxvw4x as well as lxvd2x, because for lxvw4x on an LE system the
vector elements are in LE order (right-to-left) within each
doubleword.  (Thus after lxvw2x of a <4 x float> the elements will
appear as 1, 0, 3, 2.  Following the swap, they will appear as 3, 2,
0, 1, as desired.)   For stores, an stxvd2x or stxvw4x is replaced
with an stxvd2x preceded by an xxswapd.

Introduction of extra swap instructions provides correctness, but
obviously is not ideal from a performance perspective.  Future patches
will address this with optimizations to remove most of the introduced
swaps, which have proven effective in other implementations.

The introduction of the swaps is performed during lowering of LOAD,
STORE, INTRINSIC_W_CHAIN, and INTRINSIC_VOID operations.  The latter
are used to translate intrinsics that specify the VSX loads and stores
directly into equivalent sequences for little endian.  Thus code that
uses vec_vsx_ld and vec_vsx_st does not have to be modified to be
ported from BE to LE.

We introduce new PPCISD opcodes for LXVD2X, STXVD2X, and XXSWAPD for
use during this lowering step.  In PPCInstrVSX.td, we add new SDType
and SDNode definitions for these (PPClxvd2x, PPCstxvd2x, PPCxxswapd).
These are recognized during instruction selection and mapped to the
correct instructions.

Several tests that were written to use -mcpu=pwr7 or pwr8 are modified
to disable VSX on LE variants because code generation changes with
this and subsequent patches in this set.  I chose to include all of
these in the first patch than try to rigorously sort out which tests
were broken by one or another of the patches.  Sorry about that.

The new test vsx-ldst-builtin-le.ll, and the changes to vsx-ldst.ll,
are disabled until LE support is enabled because of breakages that
occur as noted in those tests.  They are re-enabled in patch 4/4.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223783 91177308-0d34-0410-b5e6-96231b3b80d8
Move function to obtain branch weights into the BranchInst class. NFC.

Make this function available to other parts of LLVM.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223784 91177308-0d34-0410-b5e6-96231b3b80d8
Add more pattern matchers for compares, instructions, and BinaryOperators. NFC.

Add a few more matchers to make the code in the next commit more compact.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223785 91177308-0d34-0410-b5e6-96231b3b80d8
[CodeGenPrepare] Split branch conditions into multiple conditional branches.

This optimization transforms code like:
bb1:
  %0 = icmp ne i32 %a, 0
  %1 = icmp ne i32 %b, 0
  %or.cond = or i1 %0, %1
  br i1 %or.cond, label %TrueBB, label %FalseBB

into a multiple branch instructions like:

bb1:
  %0 = icmp ne i32 %a, 0
  br i1 %0, label %TrueBB, label %bb2
bb2:
  %1 = icmp ne i32 %b, 0
  br i1 %1, label %TrueBB, label %FalseBB

This optimization is already performed by SelectionDAG, but not by FastISel.
FastISel cannot perform this optimization, because it cannot generate new
MachineBasicBlocks.

Performing this optimization at CodeGenPrepare time makes it available to both -
SelectionDAG and FastISel - and the implementation in SelectiuonDAG could be
removed. There are currenty a few differences in codegen for X86 and PPC, so
this commmit only enables it for FastISel.

Reviewed by Jim Grosbach

This fixes rdar://problem/19034919.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223786 91177308-0d34-0410-b5e6-96231b3b80d8
[AVX512] Added VPBROADCAST{BWDQ} (Load with Broadcast Integer Data from General Purpose Register) encodings for AVX512-BW/VL subsets
Added encoding tests.
        


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223787 91177308-0d34-0410-b5e6-96231b3b80d8
[PowerPC 2/4] Little-endian adjustments for VSX insert/extract operations

For little endian, we need to make some straightforward adjustments in
the code expansions for scalar_to_vector and vector_extract of v2f64.
First, scalar_to_vector must place the scalar into vector element
zero.  However, our implementation of SUBREG_TO_REG will place it into
big-element vector element zero (high-order bits), and for little
endian we need it in the low-order bits.  The LE implementation splats
the high-order doubleword into the low-order doubleword.

Second, the meaning of (vector_extract x, 0) and (vector_extract x, 1)
must be reversed for similar reasons.

A new test is added that tests code generation for insertelement and
extractelement for both element 0 and element 1.  It is disabled in
this patch but enabled in patch 4/4, for reasons stated in the test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223788 91177308-0d34-0410-b5e6-96231b3b80d8
Add test cases that were inadvertently omitted from r223783 and r223788

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223789 91177308-0d34-0410-b5e6-96231b3b80d8
Remember the unmangled name in the plugin.

This allows it to work with non trivial manglings like the one in COFF.

Amusingly, this can be tested with gold, as emit-llvm causes the plugin to
exit before any COFF is generated.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223790 91177308-0d34-0410-b5e6-96231b3b80d8
[PowerPC 3/4] Little-endian adjustments for VSX vector shuffle

When performing instruction selection for ISD::VECTOR_SHUFFLE, there
is special code for handling v2f64 and v2i64 using VSX instructions.
This code must be adjusted for little-endian.  Because the two inputs
are treated as a double-wide register, we must swap their order for
little endian.  To get the appropriate mask elements to use with the
big-endian biased XXPERMDI instruction, we must reverse their order
and invert the bits.

A new test is added to test the 16 possible values of the shuffle
mask.  It is initially disabled for reasons specified in the test.  It
is re-enabled by patch 4/4.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223791 91177308-0d34-0410-b5e6-96231b3b80d8
[PowerPC 4/4] Enable little-endian support for VSX.

With the foregoing three patches, VSX instructions can be used for
little endian.  This patch removes the restriction that prevented
this, and re-enables the test cases from the first three patches.





git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223792 91177308-0d34-0410-b5e6-96231b3b80d8
Initial dsymutil tool commit.

The goal of this tool is to replicate Darwin's dsymutil functionality
based on LLVM. dsymutil is a DWARF linker. Darwin's linker (ld64) does
not link the debug information, it leaves it in the object files in
relocatable form, but embbeds a `debug map` into the executable that
describes where to find the debug information and how to relocate it.
When releasing/archiving a binary, dsymutil is called to link all the DWARF
information into a `dsym bundle` that can distributed/stored along with
the binary.

With this commit, the LLVM based dsymutil is just able to parse the STABS
debug maps embedded by ld64 in linked binaries (and not all of them, for
example archives aren't supported yet).

Note that the tool directory is called dsymutil, but the executable is
currently called llvm-dsymutil. This discrepancy will disappear once the
tool will be feature complete. At this point the executable will be renamed
to dsymutil, but until then you do not want it to override the system one.

    Differential Revision: http://reviews.llvm.org/D6242

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223793 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "Initial dsymutil tool commit."

This reverts commit r223793. The review thread wasn't concluded.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223794 91177308-0d34-0410-b5e6-96231b3b80d8