[X86] Introduce LLVM wbinvd intrinsic

[GBuella]

Summary

A previously missing intrinsic for an old instruction.

[GBuella]

The reason is, the _wbinvd intrinsic, and builtin were just recently introduced in GCC.

[craig.topper]

LGTM

[GBuella]

Rebased the patch.

include/llvm/IR/IntrinsicsX86.td

 //===----------------------------------------------------------------------===//
 // Cache-line zero
 let TargetPrefix = "x86" in {
   def int_x86_clzero : GCCBuiltin<"__builtin_ia32_clzero">,
       Intrinsic<[], [llvm_ptr_ty], []>;
 }
 
 //===----------------------------------------------------------------------===//
-// Cache line write back intrinsics
+// Cache write back intrinsics
 
-// Write back no-invalidate
 let TargetPrefix = "x86" in {
+  // Write back and invalidate
+  def int_x86_wbinvd : GCCBuiltin<"__builtin_ia32_wbinvd">,
+      Intrinsic<[], [], []>;
+
+  // Write back no-invalidate
   def int_x86_wbnoinvd : GCCBuiltin<"__builtin_ia32_wbnoinvd">,
       Intrinsic<[], [], []>;
 }

lib/Target/X86/X86InstrSystem.td

 let Defs = [EAX, EBX, ECX, EDX], Uses = [EAX, ECX] in
   def CPUID : I<0xA2, RawFrm, (outs), (ins), "cpuid", [], IIC_CPUID>, TB;
 } // SchedRW
 
 //===----------------------------------------------------------------------===//
 // Cache instructions
 let SchedRW = [WriteSystem] in {
 def INVD : I<0x08, RawFrm, (outs), (ins), "invd", [], IIC_INVD>, TB;
-def WBINVD : I<0x09, RawFrm, (outs), (ins), "wbinvd", [], IIC_INVD>, TB;
+def WBINVD : I<0x09, RawFrm, (outs), (ins), "wbinvd",
+               [(int_x86_wbinvd)], IIC_INVD>, TB;
 
 // wbnoinvd is like wbinvd, except without invalidation
 // encoding: like wbinvd + an 0xF3 prefix
 def WBNOINVD : I<0x09, RawFrm, (outs), (ins), "wbnoinvd",
                  [(int_x86_wbnoinvd)], IIC_INVD>, XS,
                  Requires<[HasWBNOINVD]>;
 } // SchedRW
 

test/CodeGen/X86/wbinvd-intrinsic.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=i686-unknown-unknown | FileCheck %s --check-prefix=i686
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s --check-prefix=x86_64
+
+define void @test_wbinvd() {
+; i686-LABEL: test_wbinvd:
+; i686:       # %bb.0:
+; i686-NEXT:    wbinvd
+; i686-NEXT:    retl
+;
+; x86_64-LABEL: test_wbinvd:
+; x86_64:       # %bb.0:
+; x86_64-NEXT:    wbinvd
+; x86_64-NEXT:    retq
+  call void @llvm.x86.wbinvd()
+  ret void
+}
+
+declare void @llvm.x86.wbinvd()