[X86] Add support for Read Time Stamp Counter x86 builtin intrinsics.

This patch:
- Adds two new X86 builtin intrinsics ('int_x86_rdtsc' and
   'int_x86_rdtscp') as GCCBuiltin intrinsics;
- Teaches the backend how to lower the two new builtins;
- Introduces a common function to lower READCYCLECOUNTER dag nodes
  and the two new rdtsc/rdtscp intrinsics;
- Improves (and extends) the existing x86 test 'rdtsc.ll'; now test 'rdtsc.ll'
  correctly verifies that both READCYCLECOUNTER and the two new intrinsics
  work fine for both 64bit and 32bit Subtargets.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207127 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 0 deletions

diff --git a/include/llvm/IR/IntrinsicsX86.td b/include/llvm/IR/IntrinsicsX86.td
index 8f64b5d8ee..e262687e91 100644
--- a/include/llvm/IR/IntrinsicsX86.td
+++ b/include/llvm/IR/IntrinsicsX86.td
@@ -18,6 +18,15 @@ let TargetPrefix = "x86" in {  // All intrinsics start with "llvm.x86.".
 }
 
 //===----------------------------------------------------------------------===//
+// Read Time Stamp Counter.
+let TargetPrefix = "x86" in {
+  def int_x86_rdtsc : GCCBuiltin<"__builtin_ia32_rdtsc">,
+              Intrinsic<[llvm_i64_ty], [], []>;
+  def int_x86_rdtscp : GCCBuiltin<"__builtin_ia32_rdtscp">,
+              Intrinsic<[llvm_i64_ty], [llvm_ptr_ty], [IntrReadWriteArgMem]>;
+}
+
+//===----------------------------------------------------------------------===//
 // 3DNow!
 
 let TargetPrefix = "x86" in {