[Constant Hoisting] Make the constant candidate map local to the collectConstantCandidates method.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204758 91177308-0d34-0410-b5e6-96231b3b80d8
[configure/make] Propagate names of build host tools when making BuildTools

When cross-compiling LLVM itself the configure/make scripts get confused when
creating the needed build host tools.  For example, building and configuring
like:

  CC_FOR_BUILD='i686-pc-linux-gnu-gcc' CXX_FOR_BUILD='i686-pc-linux-gnu-g++'
  CXX='i686-mingw32-g++' CC='i686-mingw32-gcc' LD='i686-mingw32-ld' /scratch
  /meadori/llvm-trunk/src/trunk/configure --host=i686-mingw32

  CC_FOR_BUILD='i686-pc-linux-gnu-gcc' CXX_FOR_BUILD='i686-pc-linux-gnu-g++'
  CXX='i686-mingw32-g++' CC='i686-mingw32-gcc' LD='i686-mingw32-ld' make

causes the following build break:

  checking whether the C compiler works... configure: error: cannot run C
  compiled programs.
  If you meant to cross compile, use `--host'.
  See `config.log' for more details.

The 'config.log' shows that i686-mingw32-gcc is being used to create
executables for the build host.

This patch fixes the problem by propogating the names of the build host
tools via BUILD_* when configuring/making BuildTools.

Original patch by Ekaterina Sanina.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204760 91177308-0d34-0410-b5e6-96231b3b80d8
Use Endian.h to simplify this code a bit.

While at it, factor some logic into FragmentWriter. This will allow more code
to be factored out of the fairly large ELFObjectWriter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204765 91177308-0d34-0410-b5e6-96231b3b80d8
llvm/test/DebugInfo/empty.ll: Suppress crash for targeting pecoff while investigating.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204766 91177308-0d34-0410-b5e6-96231b3b80d8
[PowerPC] Select between VSX A-type and M-type FMA instructions just before RA

The VSX instruction set has two types of FMA instructions: A-type (where the
addend is taken from the output register) and M-type (where one of the product
operands is taken from the output register). This adds a small pass that runs
just after MI scheduling (and, thus, just before register allocation) that
mutates A-type instructions (that are created during isel) into M-type
instructions when:

 1. This will eliminate an otherwise-necessary copy of the addend

 2. One of the product operands is killed by the instruction

The "right" moment to make this decision is in between scheduling and register
allocation, because only there do we know whether or not one of the product
operands is killed by any particular instruction. Unfortunately, this also
makes the implementation somewhat complicated, because the MIs are not in SSA
form and we need to preserve the LiveIntervals analysis.

As a simple example, if we have:

%vreg5<def> = COPY %vreg9; VSLRC:%vreg5,%vreg9
%vreg5<def,tied1> = XSMADDADP %vreg5<tied0>, %vreg17, %vreg16,
                        %RM<imp-use>; VSLRC:%vreg5,%vreg17,%vreg16
  ...
  %vreg9<def,tied1> = XSMADDADP %vreg9<tied0>, %vreg17, %vreg19,
                        %RM<imp-use>; VSLRC:%vreg9,%vreg17,%vreg19
  ...

We can eliminate the copy by changing from the A-type to the
M-type instruction. This means:

  %vreg5<def,tied1> = XSMADDADP %vreg5<tied0>, %vreg17, %vreg16,
                        %RM<imp-use>; VSLRC:%vreg5,%vreg17,%vreg16

is replaced by:

  %vreg16<def,tied1> = XSMADDMDP %vreg16<tied0>, %vreg18, %vreg9,
                        %RM<imp-use>; VSLRC:%vreg16,%vreg18,%vreg9

and we remove: %vreg5<def> = COPY %vreg9; VSLRC:%vreg5,%vreg9

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204768 91177308-0d34-0410-b5e6-96231b3b80d8
Create .symtab_shndxr only when needed.

We need .symtab_shndxr if and only if a symbol references a section with an
index >= 0xff00.

The old code was trying to figure out if the section was needed ahead of time,
making it a fairly dependent on the code actually writing the table. It was
also somewhat conservative and would create the section in cases where it was
not needed.

If I remember correctly, the old structure was there so that the sections were
created in the same order gas creates them. That was valuable when MC's support
for ELF was new and we tested with elf-dump.py.

This patch refactors the symbol table creation to another class and makes it
obvious that .symtab_shndxr is really only created when we are about to output
a reference to a section index >= 0xff00.

While here, also improve the tests to use macros. One file is one section
short of needing .symtab_shndxr, the second one has just the right number.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204769 91177308-0d34-0410-b5e6-96231b3b80d8
[X86] Add broadcast instructions to the table used by ExeDepsFix pass.

Adds the different broadcast instructions to the ReplaceableInstrsAVX2 table.
That way the ExeDepsFix pass can take better decisions when AVX2 broadcasts are
across domain (int <-> float).

In particular, prior to this patch we were generating:
  vpbroadcastd  LCPI1_0(%rip), %ymm2
  vpand %ymm2, %ymm0, %ymm0
  vmaxps  %ymm1, %ymm0, %ymm0 ## <- domain change penalty

Now, we generate the following nice sequence where everything is in the float
domain:
  vbroadcastss  LCPI1_0(%rip), %ymm2
  vandps  %ymm2, %ymm0, %ymm0
  vmaxps  %ymm1, %ymm0, %ymm0

<rdar://problem/16354675>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204770 91177308-0d34-0410-b5e6-96231b3b80d8
Correctly detect if a symbol uses a reserved section index or not.

The logic was incorrect for variables, causing them to end up in the wrong
section if the section had an index >= 0xff00.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204771 91177308-0d34-0410-b5e6-96231b3b80d8
DebugInfo: Add fission-related sections to COFF

Allows this test to pass on COFF platforms so we don't need to restrict
this test to a single target anymore.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204780 91177308-0d34-0410-b5e6-96231b3b80d8