diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
--- a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
@@ -515,6 +515,16 @@
 /// Insert BoundaryAlignFragment before instructions to align branches.
 void X86AsmBackend::emitInstructionBegin(MCObjectStreamer &OS,
                                          const MCInst &Inst, const MCSubtargetInfo &STI) {
+  if ((Inst.getOpcode() == X86::PREFETCHIT0 ||
+       Inst.getOpcode() == X86::PREFETCHIT1) &&
+      !isRIPRelative(Inst, *MCII)) {
+    OS.getAssembler().getContext().reportWarning(
+        Inst.getLoc(),
+        Twine((Inst.getOpcode() == X86::PREFETCHIT0 ? "'prefetchit0'"
+                                                    : "'prefetchit1'")) +
+            " only supports RIP-relative address");
+  }
+
   CanPadInst = canPadInst(Inst, OS);
 
   if (!canPadBranches(OS))
diff --git a/llvm/test/MC/X86/prefetchit-non-rip-op.s b/llvm/test/MC/X86/prefetchit-non-rip-op.s
new file mode 100644
--- /dev/null
+++ b/llvm/test/MC/X86/prefetchit-non-rip-op.s
@@ -0,0 +1,50 @@
+// RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown %s > %t 2> %t.err
+// RUN: FileCheck --check-prefix=CHECK-STDERR < %t.err %s
+
+// CHECK-STDERR: warning: 'prefetchit0' only supports RIP-relative address
+          prefetchit0 (%rdi)
+
+// CHECK-STDERR: warning: 'prefetchit1' only supports RIP-relative address
+          prefetchit1 (%rcx)
+
+// CHECK-STDERR: warning: 'prefetchit0' only supports RIP-relative address
+          prefetchit0 0x1(%rdx)
+
+// CHECK-STDERR: warning: 'prefetchit1' only supports RIP-relative address
+          prefetchit1 0x12(%rsi)
+
+// CHECK-STDERR: warning: 'prefetchit0' only supports RIP-relative address
+          prefetchit0 0x123(%r8, %rax)
+
+// CHECK-STDERR: warning: 'prefetchit1' only supports RIP-relative address
+          prefetchit1 0x1234(%r9, %r10)
+
+// CHECK-STDERR: warning: 'prefetchit0' only supports RIP-relative address
+          prefetchit0 (%r11, %r12)
+
+// CHECK-STDERR: warning: 'prefetchit1' only supports RIP-relative address
+          prefetchit1 (%r13, %r14)
+
+// CHECK-STDERR: warning: 'prefetchit0' only supports RIP-relative address
+          prefetchit0 0xabc(%rsp, %r15, 4)
+
+// CHECK-STDERR: warning: 'prefetchit1' only supports RIP-relative address
+          prefetchit1 0xffffffff(%rbp, %rdi, 8)
+
+// CHECK-STDERR: warning: 'prefetchit0' only supports RIP-relative address
+          prefetchit0 (%rsp, %rsi, 2)
+
+// CHECK-STDERR: warning: 'prefetchit1' only supports RIP-relative address
+          prefetchit1 (%rdi, %r15, 4)
+
+// CHECK-STDERR: warning: 'prefetchit0' only supports RIP-relative address
+          prefetchit0 0x80(, %r14, 8)
+
+// CHECK-STDERR: warning: 'prefetchit1' only supports RIP-relative address
+          prefetchit1 0x3(, %r8, 4)
+
+// CHECK-STDERR: warning: 'prefetchit0' only supports RIP-relative address
+          prefetchit0 (, %rax, 2)
+
+// CHECK-STDERR: warning: 'prefetchit1' only supports RIP-relative address
+          prefetchit1 (, %rcx, 8)