[X86] Custom emit __builtin_rdtscp so we can emit an explicit store f…

…or the out parameter

This is the clang side of D51803. The llvm intrinsic now returns two results. So we need to emit an explicit store in IR for the out parameter. This is similar to addcarry/subborrow/rdrand/rdseed.

Differential Revision: https://reviews.llvm.org/D51805

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@341699 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGBuiltin.cpp

@@ -9158,6 +9158,12 @@ Value *CodeGenFunction::EmitX86BuiltinExpr(unsigned BuiltinID,
   case X86::BI__rdtsc: {
     return Builder.CreateCall(CGM.getIntrinsic(Intrinsic::x86_rdtsc));
   }
+  case X86::BI__builtin_ia32_rdtscp: {
+    Value *Call = Builder.CreateCall(CGM.getIntrinsic(Intrinsic::x86_rdtscp));
+    Builder.CreateDefaultAlignedStore(Builder.CreateExtractValue(Call, 1),
+                                      Ops[0]);
+    return Builder.CreateExtractValue(Call, 0);
+  }
   case X86::BI__builtin_ia32_undef128:
   case X86::BI__builtin_ia32_undef256:
   case X86::BI__builtin_ia32_undef512:

test/CodeGen/rd-builtins.c

@@ -14,3 +14,12 @@ int test_rdtsc() {
 // CHECK: @test_rdtsc
 // CHECK: call i64 @llvm.x86.rdtsc
 }
+
+unsigned long long test_rdtscp(unsigned int *a) {
+// CHECK: @test_rdtscp
+// CHECK: [[RDTSCP:%.*]] = call { i64, i32 } @llvm.x86.rdtscp
+// CHECK: [[TSC_AUX:%.*]] = extractvalue { i64, i32 } [[RDTSCP]], 1
+// CHECK: store i32 [[TSC_AUX]], i32* %{{.*}}
+// CHECK: [[TSC:%.*]] = extractvalue { i64, i32 } [[RDTSCP]], 0
+  return __rdtscp(a);
+}