[CUDA] CUDA has no device-side library builtins.

We should (almost) never consider a device-side declaration to match a
library builtin functio.  Otherwise clang may ignore the implementation
provided by the CUDA headers and emit clang's idea of the builtin.

Differential Revision: https://reviews.llvm.org/D42319

llvm-svn: 323239

1 files changed, 22 insertions, 0 deletions

diff --git a/clang/test/CodeGenCUDA/library-builtin.cu b/clang/test/CodeGenCUDA/library-builtin.cu
new file mode 100644
index 00000000000..4804c75cde3
--- /dev/null
+++ b/clang/test/CodeGenCUDA/library-builtin.cu
@@ -0,0 +1,22 @@
+// REQUIRES: x86-registered-target
+// REQUIRES: nvptx-registered-target
+
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -o - %s | \
+// RUN:  FileCheck --check-prefixes=HOST,BOTH %s
+// RUN: %clang_cc1 -fcuda-is-device -triple nvptx64-nvidia-cuda \
+// RUN:   -emit-llvm -o - %s | FileCheck %s --check-prefixes=DEVICE,BOTH
+
+// BOTH-LABEL: define float @logf(float
+
+// logf() should be calling itself recursively as we don't have any standard
+// library on device side.
+// DEVICE: call float @logf(float
+extern "C" __attribute__((device)) float logf(float __x) { return logf(__x); }
+
+// NOTE: this case is to illustrate the expected differences in behavior between
+// the host and device. In general we do not mess with host-side standard
+// library.
+//
+// Host is assumed to have standard library, so logf() calls LLVM intrinsic.
+// HOST: call float @llvm.log.f32(float
+extern "C" float logf(float __x) { return logf(__x); }