[GPGPU] Add support for NVIDIA libdevice

Summary:
This allows us to map functions such as exp, expf, expl, for which no
LLVM intrinsics exist. Instead, we link to NVIDIA's libdevice which provides
high-performance implementations of a wide range of (math) functions. We
currently link only a small subset, the exp, cos and copysign functions. Other
functions will be enabled as needed.

Reviewers: bollu, singam-sanjay

Reviewed By: bollu

Subscribers: tstellar, tra, nemanjai, pollydev, mgorny, llvm-commits, kbarton

Tags: #polly

Differential Revision: https://reviews.llvm.org/D35703

llvm-svn: 309560
diff --git a/polly/test/lit.site.cfg.in b/polly/test/lit.site.cfg.in
index 2ffef28..1707f66 100644
--- a/polly/test/lit.site.cfg.in
+++ b/polly/test/lit.site.cfg.in
@@ -31,6 +31,11 @@
     key, = e.args
     lit_config.fatal("unable to find %r parameter, use '--param=%s=VALUE'" % (key,key))
 
+# excludes: A list of directories to exclude from the testsuite. The 'Inputs'
+# subdirectories contain auxiliary inputs for various tests in their parent
+# directories.
+config.excludes = ['Inputs']
+
 if config.link_polly_into_tools == '' or \
    config.link_polly_into_tools.lower() == '0' or \
    config.link_polly_into_tools.lower() == 'n' or \