Adding front-end support to several intrinsics (bit scanning, conversion and state reading intrinsics)

Adding LLVM front-end support to two intrinsics dealing with bit scan: _bit_scan_forward and _bit_scan_reverse.
 Their functionality is as described in Intel intrinsics guide:
 https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_bit_scan_forward&expand=371,370
 https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_bit_scan_reverse&expand=371,370

 Furthermore, adding clang front-end support to these conversion intrinsics: _mm256_cvtsd_f64, _mm256_cvtsi256_si32 and _mm256_cvtss_f32.

 Finally, adding tests to all of the above, as well as to the state reading intrinsics _rdpmc and _rdtsc.
  Their functionality is also specified in the Intel intrinsics guide.


Commit on behalf of Omer Paparo Bivas

llvm-svn: 271387

1 files changed, 17 insertions, 0 deletions

diff --git a/clang/test/CodeGen/bitscan-builtins.c b/clang/test/CodeGen/bitscan-builtins.c
new file mode 100644
index 00000000000..85a75426342
--- /dev/null
+++ b/clang/test/CodeGen/bitscan-builtins.c
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s | FileCheck %s
+
+// Don't include mm_malloc.h, it's system specific.
+#define __MM_MALLOC_H
+#include <immintrin.h>
+
+int test_bit_scan_forward(int a) {
+  return _bit_scan_forward(a);
+// CHECK: @test_bit_scan_forward
+// CHECK: call i32 @llvm.x86.bit.scan.forward
+}
+
+int test_bit_scan_reverse(int a) {
+  return _bit_scan_reverse(a);
+// CHECK: @test_bit_scan_reverse
+// CHECK: call i32 @llvm.x86.bit.scan.reverse
+}