gtest-death-test.cc: Move ~DeathTestFactory() to unbreak cygming build since r194865.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194918 91177308-0d34-0410-b5e6-96231b3b80d8
Fix filename in header comment

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194924 91177308-0d34-0410-b5e6-96231b3b80d8
InstCombine: fold (A >> C) == (B >> C) --> (A^B) < (1 << C) for constant Cs.

This is common in bitfield code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194925 91177308-0d34-0410-b5e6-96231b3b80d8
Use array_pod_sort instead of std::sort

Per Rafael's review of r194514.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194926 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Make dot_4 instructions predicable

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194927 91177308-0d34-0410-b5e6-96231b3b80d8
Annotate APInt methods where it's not clear whether they are in place with warn_unused_result.

Fix ScalarEvolution bugs uncovered by this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194928 91177308-0d34-0410-b5e6-96231b3b80d8
ScalarEvolution: Warn if the result of setFlags/clearFlags is unused.

This was a source of bugs in the past.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194929 91177308-0d34-0410-b5e6-96231b3b80d8
Fix codegen for null different sized pointer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194932 91177308-0d34-0410-b5e6-96231b3b80d8
Fix assert on unaligned access to global with different address space size.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194934 91177308-0d34-0410-b5e6-96231b3b80d8
Apply the InstCombine fptrunc sqrt optimization to llvm.sqrt

InstCombine, in visitFPTrunc, applies the following optimization to sqrt calls:

  (fptrunc (sqrt (fpext x))) -> (sqrtf x)

but does not apply the same optimization to llvm.sqrt. This is a problem
because, to enable vectorization, Clang generates llvm.sqrt instead of sqrt in
fast-math mode, and because this optimization is being applied to sqrt and not
applied to llvm.sqrt, sometimes the fast-math code is slower.

This change makes InstCombine apply this optimization to llvm.sqrt as well.

This fixes the specific problem in PR17758, although the same underlying issue
(optimizations applied to libcalls are not applied to intrinsics) exists for
other optimizations in SimplifyLibCalls.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194935 91177308-0d34-0410-b5e6-96231b3b80d8
The WebKit_JS CC preserves the same registers as the C CC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194936 91177308-0d34-0410-b5e6-96231b3b80d8
Add a loop rerolling pass

This adds a loop rerolling pass: the opposite of (partial) loop unrolling. The
transformation aims to take loops like this:

for (int i = 0; i < 3200; i += 5) {
  a[i]     += alpha * b[i];
  a[i + 1] += alpha * b[i + 1];
  a[i + 2] += alpha * b[i + 2];
  a[i + 3] += alpha * b[i + 3];
  a[i + 4] += alpha * b[i + 4];
}

and turn them into this:

for (int i = 0; i < 3200; ++i) {
  a[i] += alpha * b[i];
}

and loops like this:

for (int i = 0; i < 500; ++i) {
  x[3*i] = foo(0);
  x[3*i+1] = foo(0);
  x[3*i+2] = foo(0);
}

and turn them into this:

for (int i = 0; i < 1500; ++i) {
  x[i] = foo(0);
}

There are two motivations for this transformation:

  1. Code-size reduction (especially relevant, obviously, when compiling for
code size).

  2. Providing greater choice to the loop vectorizer (and generic unroller) to
choose the unrolling factor (and a better ability to vectorize). The loop
vectorizer can take vector lengths and register pressure into account when
choosing an unrolling factor, for example, and a pre-unrolled loop limits that
choice. This is especially problematic if the manual unrolling was optimized
for a machine different from the current target.

The current implementation is limited to single basic-block loops only. The
rerolling recognition should work regardless of how the loop iterations are
intermixed within the loop body (subject to dependency and side-effect
constraints), but the significant restriction is that the order of the
instructions in each iteration must be identical. This seems sufficient to
capture all current use cases.

This pass is not currently enabled by default at any optimization level.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194939 91177308-0d34-0410-b5e6-96231b3b80d8
Use right address space pointer size

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194940 91177308-0d34-0410-b5e6-96231b3b80d8
Fix ndebug-build unused variable in loop rerolling

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194941 91177308-0d34-0410-b5e6-96231b3b80d8
Added a size field to the stack map record to handle subregister spills.

Implementing this on bigendian platforms could get strange. I added a
target hook, getStackSlotRange, per Jakob's recommendation to make
this as explicit as possible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194942 91177308-0d34-0410-b5e6-96231b3b80d8
Add the cold attribute to error-reporting call sites

Generally speaking, control flow paths with error reporting calls are cold.
So far, error reporting calls are calls to perror and calls to fprintf,
fwrite, etc. with stderr as the stream. This can be extended in the future.

The primary motivation is to improve block placement (the cold attribute
affects the static branch prediction heuristics).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194943 91177308-0d34-0410-b5e6-96231b3b80d8
Use getZExtOrTrunc instead of repeating the same logic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194944 91177308-0d34-0410-b5e6-96231b3b80d8
Use more getZExtOrTruncs

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194945 91177308-0d34-0410-b5e6-96231b3b80d8
[PM] Completely remove support for explicit 'require' methods on the
AnalysisManager. All this method did was assert something and we have
a perfectly good way to trigger that assert from the query path.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194947 91177308-0d34-0410-b5e6-96231b3b80d8
[block-freq] Add BlockFrequency::scale that returns a remainder from the division and make the private scale in BlockFrequency more performant.

This change is the first in a series of changes improving LLVM's Block
Frequency propogation implementation to not lose probability mass in
branchy code when propogating block frequency information from a basic
block to its successors. This patch is a simple infrastructure
improvement that does not actually modify the block frequency
algorithm. The specific changes are:

1. Changes the division algorithm used when scaling block frequencies by
branch probabilities to a short division algorithm. This gives us the
remainder for free as well as provides a nice speed boost. When I
benched the old routine and the new routine on a Sandy Bridge iMac with
disabled turbo mode performing 8192 iterations on an array of length
32768, I saw ~600% increase in speed in mean/median performance.

2. Exposes a scale method that returns a remainder. This is important so
we can ensure that when we scale a block frequency by some branch
probability BP = N/D, the remainder from the division by D can be
retrieved and propagated to other children to ensure no probability mass
is lost (more to come on this).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194950 91177308-0d34-0410-b5e6-96231b3b80d8