[NVPTX] Improve handling of FP fusion

We now consider the FPOpFusion flag when determining whether
to fuse ops.  We also explicitly emit add.rn when fusion is
disabled to prevent ptxas from fusing the operations on its
own.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213287 91177308-0d34-0410-b5e6-96231b3b80d8
Typo: exists -> exits

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213290 91177308-0d34-0410-b5e6-96231b3b80d8
[ASan] Don't instrument load/stores with !nosanitize metadata.

This is used to avoid instrumentation of instructions added by UBSan
in Clang frontend (see r213291). This fixes PR20085.

Reviewed in http://reviews.llvm.org/D4544.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213292 91177308-0d34-0410-b5e6-96231b3b80d8