Fix a pair of use after free. Should bring the bots back.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216005 91177308-0d34-0410-b5e6-96231b3b80d8
Reapply [FastISel] Let the target decide first if it wants to materialize a constant (215588).

Note: This was originally reverted to track down a buildbot error. This commit
exposed a latent bug that was fixed in r215753. Therefore it is reapplied
without any modifications.

I run it through SPEC2k and SPEC2k6 for AArch64 and it didn't introduce any new
regeressions.

Original commit message:
This changes the order in which FastISel tries to materialize a constant.
Originally it would try to use a simple target-independent approach, which
can lead to the generation of inefficient code.

On X86 this would result in the use of movabsq to materialize any 64bit
integer constant - even for simple and small values such as 0 and 1. Also
some very funny floating-point materialization could be observed too.

On AArch64 it would materialize the constant 0 in a register even the
architecture has an actual "zero" register.

On ARM it would generate unnecessary mov instructions or not use mvn.

This change simply changes the order and always asks the target first if it
likes to materialize the constant. This doesn't fix all the issues
mentioned above, but it enables the targets to implement such
optimizations.

Related to <rdar://problem/17420988>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216006 91177308-0d34-0410-b5e6-96231b3b80d8
IR: De-duplicate code for replacing operands in place

This is non-trivial and sits in three places.  Move it to
ConstantUniqueMap.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216007 91177308-0d34-0410-b5e6-96231b3b80d8
ADT: Unit test for ArrayRef::equals change in r215986

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216008 91177308-0d34-0410-b5e6-96231b3b80d8
Reapply [FastISel][AArch64] Make use of the zero register when possible (r215591).

Note: This was originally reverted to track down a buildbot error. Reapply
without any modifications.

Original commit message:
This change materializes now the value "0" from the zero register.
The zero register can be folded by several instruction, so no
materialization is need at all.

Fixes <rdar://problem/17924413>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216009 91177308-0d34-0410-b5e6-96231b3b80d8
Reapply [FastISel][X86] Emit more efficient instructions for integer constant materialization (r215593).

Note: This was originally reverted to track down a buildbot error. Reapply
without any modifications.

Original commit message:
This mostly affects the i64 value type, which always resulted in an 15byte
mobavsq instruction to materialize any constant. The custom code checks the
value of the immediate and tries to use a different and smaller mov
instruction when possible.

This fixes <rdar://problem/17420988>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216010 91177308-0d34-0410-b5e6-96231b3b80d8
Reapply [FastISel][X86] Use XOR to materialize the "0" value (r215594).

Note: This was originally reverted to track down a buildbot error. Reapply
without any modifications.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216011 91177308-0d34-0410-b5e6-96231b3b80d8
Reapply [FastISel][X86] Add large code model support for materializing floating-point constants (r215595).

Note: This was originally reverted to track down a buildbot error. Reapply
without any modifications.

Original commit message:
In the large code model for X86 floating-point constants are placed in the
constant pool and materialized by loading from it. Since the constant pool
could be far away, a PC relative load might not work. Therefore we first
materialize the address of the constant pool with a movabsq and then load
from there the floating-point value.

Fixes <rdar://problem/17674628>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216012 91177308-0d34-0410-b5e6-96231b3b80d8
Reapply [FastISel][AArch64] Add support for more addressing modes (r215597).

Note: This was originally reverted to track down a buildbot error. Reapply
without any modifications.

Original commit message:
FastISel didn't take much advantage of the different addressing modes available
to it on AArch64. This commit allows the ComputeAddress method to recognize more
addressing modes that allows shifts and sign-/zero-extensions to be folded into
the memory operation itself.

For Example:
  lsl x1, x1, #3     --> ldr x0, [x0, x1, lsl #3]
  ldr x0, [x0, x1]

  sxtw x1, w1
  lsl x1, x1, #3     --> ldr x0, [x0, x1, sxtw #3]
  ldr x0, [x0, x1]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216013 91177308-0d34-0410-b5e6-96231b3b80d8
Fix the MSVC build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216014 91177308-0d34-0410-b5e6-96231b3b80d8
IR: Thread OnlyIfReduced through ConstantExpr::getWithOperands()

In order to change `ConstantExpr::replaceUsesOfWithOnConstant()` to work
like other constants (e.g., using `ConstantArray::getImpl()`), thread
`OnlyIfReduced` through as necessary.  When `OnlyIfReduced` is false,
there's no functionality change.  When it's true, if there's no constant
folding or type changes `nullptr` is returned instead of the new
constant.

`ConstantExpr::replaceUsesOfWithOnConstant()` will be updated to use the
"true" version in a follow-up commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216015 91177308-0d34-0410-b5e6-96231b3b80d8