Update TargetLowering ivars for name policy.

http://llvm.org/docs/CodingStandards.html#name-types-functions-variables-and-enumerators-properly

ivars should be camel-case and start with an upper-case letter. A few in
TargetLowering were starting with a lower-case letter.

No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175667 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Update for name changes from r175667.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175668 91177308-0d34-0410-b5e6-96231b3b80d8
DAGCombiner: Fold pointless truncate, bitcast, buildvector series

(2xi32) (truncate ((2xi64) bitcast (buildvector i32 a, i32 x, i32 b, i32 y)))
can be folded into a (2xi32) (buildvector i32 a, i32 b).

Such a DAG would cause uneccessary vdup instructions followed by vmovn
instructions.

We generate this code on ARM NEON for a setcc olt, 2xf64, 2xf64. For example, in
the vectorized version of the code below.

double A[N];
double B[N];

void test_double_compare_to_double() {
  int i;
  for(i=0;i<N;i++)
    A[i] = (double)(A[i] < B[i]);
}

radar://13191881

Fixes bug 15283.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175670 91177308-0d34-0410-b5e6-96231b3b80d8