[X86][1/2] Support PREFETCHI instructions

For more details about these instructions, please refer to the latest ISE document: https://www.intel.com/content/www/us/en/develop/download/intel-architecture-instruction-set-extensions-programming-reference.html

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D136040

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index c33798e..1a4db1f 100644 (file)
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -587,6 +587,7 @@ X86 Support in Clang
 - Support ``-mindirect-branch-cs-prefix`` for call and jmp to indirect thunk.
 - Fix 32-bit ``__fastcall`` and ``__vectorcall`` ABI mismatch with MSVC.
 - Switch ``AVX512-BF16`` intrinsics types from ``short`` to ``__bf16``.
+- Add support for ``PREFETCHI`` instructions.
 
 DWARF Support in Clang
 ----------------------

diff --git a/clang/include/clang/Basic/BuiltinsX86_64.def b/clang/include/clang/Basic/BuiltinsX86_64.def
index 81cda3c..0a06613 100644 (file)
--- a/clang/include/clang/Basic/BuiltinsX86_64.def
+++ b/clang/include/clang/Basic/BuiltinsX86_64.def
@@ -133,6 +133,8 @@ TARGET_BUILTIN(__builtin_ia32_tdpbuud, "vIUcIUcIUc", "n", "amx-int8")
 TARGET_BUILTIN(__builtin_ia32_tdpbf16ps, "vIUcIUcIUc", "n", "amx-bf16")
 TARGET_BUILTIN(__builtin_ia32_ptwrite64, "vUOi", "n", "ptwrite")
 
+TARGET_BUILTIN(__builtin_ia32_prefetchi, "vvC*Ui", "nc", "prefetchi")
+
 #undef BUILTIN
 #undef TARGET_BUILTIN
 #undef TARGET_HEADER_BUILTIN

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index a4c6f20..3f975d7 100644 (file)
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -4647,6 +4647,8 @@ def mpconfig : Flag<["-"], "mpconfig">, Group<m_x86_Features_Group>;
 def mno_pconfig : Flag<["-"], "mno-pconfig">, Group<m_x86_Features_Group>;
 def mpopcnt : Flag<["-"], "mpopcnt">, Group<m_x86_Features_Group>;
 def mno_popcnt : Flag<["-"], "mno-popcnt">, Group<m_x86_Features_Group>;
+def mprefetchi : Flag<["-"], "mprefetchi">, Group<m_x86_Features_Group>;
+def mno_prefetchi : Flag<["-"], "mno-prefetchi">, Group<m_x86_Features_Group>;
 def mprefetchwt1 : Flag<["-"], "mprefetchwt1">, Group<m_x86_Features_Group>;
 def mno_prefetchwt1 : Flag<["-"], "mno-prefetchwt1">, Group<m_x86_Features_Group>;
 def mprfchw : Flag<["-"], "mprfchw">, Group<m_x86_Features_Group>;

diff --git a/clang/lib/Basic/Targets/X86.cpp b/clang/lib/Basic/Targets/X86.cpp
index 46a5516..17a139a 100644 (file)
--- a/clang/lib/Basic/Targets/X86.cpp
+++ b/clang/lib/Basic/Targets/X86.cpp
@@ -290,6 +290,8 @@ bool X86TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
       HasCLWB = true;
     } else if (Feature == "+wbnoinvd") {
       HasWBNOINVD = true;
+    } else if (Feature == "+prefetchi") {
+      HasPREFETCHI = true;
     } else if (Feature == "+prefetchwt1") {
       HasPREFETCHWT1 = true;
     } else if (Feature == "+clzero") {
@@ -738,6 +740,8 @@ void X86TargetInfo::getTargetDefines(const LangOptions &Opts,
     Builder.defineMacro("__SHSTK__");
   if (HasSGX)
     Builder.defineMacro("__SGX__");
+  if (HasPREFETCHI)
+    Builder.defineMacro("__PREFETCHI__");
   if (HasPREFETCHWT1)
     Builder.defineMacro("__PREFETCHWT1__");
   if (HasCLZERO)
@@ -929,6 +933,7 @@ bool X86TargetInfo::isValidFeatureName(StringRef Name) const {
       .Case("pconfig", true)
       .Case("pku", true)
       .Case("popcnt", true)
+      .Case("prefetchi", true)
       .Case("prefetchwt1", true)
       .Case("prfchw", true)
       .Case("ptwrite", true)
@@ -1025,6 +1030,7 @@ bool X86TargetInfo::hasFeature(StringRef Feature) const {
       .Case("pconfig", HasPCONFIG)
       .Case("pku", HasPKU)
       .Case("popcnt", HasPOPCNT)
+      .Case("prefetchi", HasPREFETCHI)
       .Case("prefetchwt1", HasPREFETCHWT1)
       .Case("prfchw", HasPRFCHW)
       .Case("ptwrite", HasPTWRITE)

diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index 7c1fe0d..1feb32e 100644 (file)
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -123,6 +123,7 @@ class LLVM_LIBRARY_VISIBILITY X86TargetInfo : public TargetInfo {
   bool HasCLFLUSHOPT = false;
   bool HasCLWB = false;
   bool HasMOVBE = false;
+  bool HasPREFETCHI = false;
   bool HasPREFETCHWT1 = false;
   bool HasRDPID = false;
   bool HasRDPRU = false;

diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 6bf0218..54eb520 100644 (file)
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -15479,6 +15479,11 @@ Value *CodeGenFunction::EmitX86BuiltinExpr(unsigned BuiltinID,
     static constexpr int Mask[] = {0, 5, 6, 7};
     return Builder.CreateShuffleVector(Call, Ops[2], Mask);
   }
+  case X86::BI__builtin_ia32_prefetchi:
+    return Builder.CreateCall(
+        CGM.getIntrinsic(Intrinsic::prefetch, Ops[0]->getType()),
+        {Ops[0], llvm::ConstantInt::get(Int32Ty, 0), Ops[1],
+         llvm::ConstantInt::get(Int32Ty, 0)});
   }
 }
 

diff --git a/clang/lib/Headers/CMakeLists.txt b/clang/lib/Headers/CMakeLists.txt
index bd2161d..a095c93 100644 (file)
--- a/clang/lib/Headers/CMakeLists.txt
+++ b/clang/lib/Headers/CMakeLists.txt
@@ -174,6 +174,7 @@ set(x86_files
   pkuintrin.h
   pmmintrin.h
   popcntintrin.h
+  prfchiintrin.h
   prfchwintrin.h
   ptwriteintrin.h
   rdpruintrin.h

diff --git a/clang/lib/Headers/cpuid.h b/clang/lib/Headers/cpuid.h
index 442ef5b..7d823ba 100644 (file)
--- a/clang/lib/Headers/cpuid.h
+++ b/clang/lib/Headers/cpuid.h
@@ -204,6 +204,9 @@
 #define bit_AVX512BF16    0x00000020
 #define bit_HRESET        0x00400000
 
+/* Features in %edx for leaf 7 sub-leaf 1 */
+#define bit_PREFETCHI     0x00004000
+
 /* Features in %eax for leaf 13 sub-leaf 1 */
 #define bit_XSAVEOPT    0x00000001
 #define bit_XSAVEC      0x00000002

diff --git a/clang/lib/Headers/prfchiintrin.h b/clang/lib/Headers/prfchiintrin.h
new file mode 100644 (file)
index 0000000..36600b2
--- /dev/null
+++ b/clang/lib/Headers/prfchiintrin.h
@@ -0,0 +1,61 @@
+/*===---- prfchiintrin.h - PREFETCHI intrinsic -----------------------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __PRFCHIINTRIN_H
+#define __PRFCHIINTRIN_H
+
+#ifdef __x86_64__
+
+/* Define the default attributes for the functions in this file. */
+#define __DEFAULT_FN_ATTRS                                                     \
+  __attribute__((__always_inline__, __nodebug__, __target__("prefetchi")))
+
+/// Loads an instruction sequence containing the specified memory address into
+///    all level cache.
+///
+///    Note that the effect of this intrinsic is dependent on the processor
+///    implementation.
+///
+/// \headerfile <x86intrin.h>
+///
+/// This intrinsic corresponds to the \c PREFETCHIT0 instruction.
+///
+/// \param __P
+///    A pointer specifying the memory address to be prefetched.
+static __inline__ void __DEFAULT_FN_ATTRS
+_m_prefetchit0(volatile const void *__P) {
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wcast-qual"
+  __builtin_ia32_prefetchi((const void *)__P, 3 /* _MM_HINT_T0 */);
+#pragma clang diagnostic pop
+}
+
+/// Loads an instruction sequence containing the specified memory address into
+///    all but the first-level cache.
+///
+///    Note that the effect of this intrinsic is dependent on the processor
+///    implementation.
+///
+/// \headerfile <x86intrin.h>
+///
+/// This intrinsic corresponds to the \c PREFETCHIT1 instruction.
+///
+/// \param __P
+///    A pointer specifying the memory address to be prefetched.
+static __inline__ void __DEFAULT_FN_ATTRS
+_m_prefetchit1(volatile const void *__P) {
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wcast-qual"
+  __builtin_ia32_prefetchi((const void *)__P, 2 /* _MM_HINT_T1 */);
+#pragma clang diagnostic pop
+}
+#endif /* __x86_64__ */
+#undef __DEFAULT_FN_ATTRS
+
+#endif /* __PRFCHWINTRIN_H */

diff --git a/clang/lib/Headers/x86gprintrin.h b/clang/lib/Headers/x86gprintrin.h
index 81d7360..4bf0472 100644 (file)
--- a/clang/lib/Headers/x86gprintrin.h
+++ b/clang/lib/Headers/x86gprintrin.h
@@ -25,6 +25,11 @@
 #include <crc32intrin.h>
 #endif
 
+#if !(defined(_MSC_VER) || defined(__SCE__)) || __has_feature(modules) ||      \
+    defined(__PRFCHI__)
+#include <prfchiintrin.h>
+#endif
+
 #if defined(__i386__)
 #define __SAVE_GPRBX "mov {%%ebx, %%eax |eax, ebx};"
 #define __RESTORE_GPRBX "mov {%%eax, %%ebx |ebx, eax};"

diff --git a/clang/test/CodeGen/X86/prefetchi-builtins.c b/clang/test/CodeGen/X86/prefetchi-builtins.c
new file mode 100644 (file)
index 0000000..c822f7c
--- /dev/null
+++ b/clang/test/CodeGen/X86/prefetchi-builtins.c
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -ffreestanding -triple x86_64-unknown-unknown -target-feature +prefetchi -emit-llvm -o - %s | FileCheck %s
+
+
+#include <x86intrin.h>
+
+void test_m_prefetch_it0(void *p) {
+  return _m_prefetchit0(p);
+  // CHECK-LABEL: define{{.*}} void @test_m_prefetch_it0
+  // CHECK: call void @llvm.prefetch.p0(ptr {{.*}}, i32 0, i32 3, i32 0)
+}
+
+void test_m_prefetch_it1(void *p) {
+  return _m_prefetchit1(p);
+  // CHECK-LABEL: define{{.*}} void @test_m_prefetch_it1
+  // CHECK: call void @llvm.prefetch.p0(ptr {{.*}}, i32 0, i32 2, i32 0)
+}

diff --git a/clang/test/Driver/x86-target-features.c b/clang/test/Driver/x86-target-features.c
index d30215d..d113eeb 100644 (file)
--- a/clang/test/Driver/x86-target-features.c
+++ b/clang/test/Driver/x86-target-features.c
@@ -91,6 +91,11 @@
 // PREFETCHWT1: "-target-feature" "+prefetchwt1"
 // NO-PREFETCHWT1: "-target-feature" "-prefetchwt1"
 
+// RUN: %clang --target=i386 -march=i386 -mprefetchi %s -### -o %t.o 2>&1 | FileCheck -check-prefix=PREFETCHI %s
+// RUN: %clang --target=i386 -march=i386 -mno-prefetchi %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NO-PREFETCHI %s
+// PREFETCHI: "-target-feature" "+prefetchi"
+// NO-PREFETCHI: "-target-feature" "-prefetchi"
+
 // RUN: %clang --target=i386 -march=i386 -mclzero %s -### 2>&1 | FileCheck -check-prefix=CLZERO %s
 // RUN: %clang --target=i386 -march=i386 -mno-clzero %s -### 2>&1 | FileCheck -check-prefix=NO-CLZERO %s
 // CLZERO: "-target-feature" "+clzero"

diff --git a/llvm/include/llvm/Support/X86TargetParser.def b/llvm/include/llvm/Support/X86TargetParser.def
index 1a928e5..a617d49 100644 (file)
--- a/llvm/include/llvm/Support/X86TargetParser.def
+++ b/llvm/include/llvm/Support/X86TargetParser.def
@@ -174,6 +174,7 @@ X86_FEATURE       (MOVDIRI,         "movdiri")
 X86_FEATURE       (MWAITX,          "mwaitx")
 X86_FEATURE       (PCONFIG,         "pconfig")
 X86_FEATURE       (PKU,             "pku")
+X86_FEATURE       (PREFETCHI,       "prefetchi")
 X86_FEATURE       (PREFETCHWT1,     "prefetchwt1")
 X86_FEATURE       (PRFCHW,          "prfchw")
 X86_FEATURE       (PTWRITE,         "ptwrite")

diff --git a/llvm/lib/Support/Host.cpp b/llvm/lib/Support/Host.cpp
index 5949930..1cf67aa 100644 (file)
--- a/llvm/lib/Support/Host.cpp
+++ b/llvm/lib/Support/Host.cpp
@@ -1808,6 +1808,7 @@ bool sys::getHostCPUFeatures(StringMap<bool> &Features) {
   Features["avxvnni"]    = HasLeaf7Subleaf1 && ((EAX >> 4) & 1) && HasAVXSave;
   Features["avx512bf16"] = HasLeaf7Subleaf1 && ((EAX >> 5) & 1) && HasAVX512Save;
   Features["hreset"]     = HasLeaf7Subleaf1 && ((EAX >> 22) & 1);
+  Features["prefetchi"]  = HasLeaf7Subleaf1 && ((EDX >> 14) & 1);
 
   bool HasLeafD = MaxLevel >= 0xd &&
                   !getX86CpuIDAndInfoEx(0xd, 0x1, &EAX, &EBX, &ECX, &EDX);

diff --git a/llvm/lib/Support/X86TargetParser.cpp b/llvm/lib/Support/X86TargetParser.cpp
index 8c65542..58736c7 100644 (file)
--- a/llvm/lib/Support/X86TargetParser.cpp
+++ b/llvm/lib/Support/X86TargetParser.cpp
@@ -581,6 +581,7 @@ constexpr FeatureBitset ImpliedFeaturesAMX_BF16 = FeatureAMX_TILE;
 constexpr FeatureBitset ImpliedFeaturesAMX_INT8 = FeatureAMX_TILE;
 constexpr FeatureBitset ImpliedFeaturesHRESET = {};
 
+static constexpr FeatureBitset ImpliedFeaturesPREFETCHI = {};
 static constexpr FeatureBitset ImpliedFeaturesAVX512FP16 =
     FeatureAVX512BW | FeatureAVX512DQ | FeatureAVX512VL;
 // Key Locker Features

diff --git a/llvm/lib/Target/X86/X86.td b/llvm/lib/Target/X86/X86.td
index bb141b4..c34d803 100644 (file)
--- a/llvm/lib/Target/X86/X86.td
+++ b/llvm/lib/Target/X86/X86.td
@@ -134,6 +134,9 @@ def FeatureVPOPCNTDQ : SubtargetFeature<"avx512vpopcntdq", "HasVPOPCNTDQ",
 def FeaturePFI      : SubtargetFeature<"avx512pf", "HasPFI", "true",
                       "Enable AVX-512 PreFetch Instructions",
                                       [FeatureAVX512]>;
+def FeaturePREFETCHI  : SubtargetFeature<"prefetchi", "HasPREFETCHI",
+                                   "true",
+                                   "Prefetch instruction with T0 or T1 Hint">;
 def FeaturePREFETCHWT1  : SubtargetFeature<"prefetchwt1", "HasPREFETCHWT1",
                                    "true",
                                    "Prefetch with Intent to Write and T1 Hint">;

diff --git a/llvm/lib/Target/X86/X86DiscriminateMemOps.cpp b/llvm/lib/Target/X86/X86DiscriminateMemOps.cpp
index 29668f4..03ee685 100644 (file)
--- a/llvm/lib/Target/X86/X86DiscriminateMemOps.cpp
+++ b/llvm/lib/Target/X86/X86DiscriminateMemOps.cpp
@@ -73,7 +73,8 @@ public:
 
 bool IsPrefetchOpcode(unsigned Opcode) {
   return Opcode == X86::PREFETCHNTA || Opcode == X86::PREFETCHT0 ||
-         Opcode == X86::PREFETCHT1 || Opcode == X86::PREFETCHT2;
+         Opcode == X86::PREFETCHT1 || Opcode == X86::PREFETCHT2 ||
+         Opcode == X86::PREFETCHIT0 || Opcode == X86::PREFETCHIT1;
 }
 } // end anonymous namespace
 

diff --git a/llvm/lib/Target/X86/X86InstrInfo.td b/llvm/lib/Target/X86/X86InstrInfo.td
index 9f2cd2e..9da87c4 100644 (file)
--- a/llvm/lib/Target/X86/X86InstrInfo.td
+++ b/llvm/lib/Target/X86/X86InstrInfo.td
@@ -956,6 +956,7 @@ def HasSGX       : Predicate<"Subtarget->hasSGX()">;
 def HasRDSEED    : Predicate<"Subtarget->hasRDSEED()">;
 def HasSSEPrefetch : Predicate<"Subtarget->hasSSEPrefetch()">;
 def NoSSEPrefetch : Predicate<"!Subtarget->hasSSEPrefetch()">;
+def HasPREFETCHI : Predicate<"Subtarget->hasPREFETCHI()">;
 def HasPrefetchW : Predicate<"Subtarget->hasPrefetchW()">;
 def HasPREFETCHWT1 : Predicate<"Subtarget->hasPREFETCHWT1()">;
 def HasLAHFSAHF  : Predicate<"Subtarget->hasLAHFSAHF()">;
@@ -2999,6 +3000,16 @@ let Predicates = [HasUINTR, In64BitMode], SchedRW = [WriteSystem] in {
 }
 
 //===----------------------------------------------------------------------===//
+// PREFETCHIT0 and PREFETCHIT1 Instructions
+// prefetch ADDR, RW, Locality, Data
+let Predicates = [HasPREFETCHI, In64BitMode], SchedRW = [WriteLoad] in {
+  def PREFETCHIT0 : I<0x18, MRM7m, (outs), (ins i8mem:$src),
+    "prefetchit0\t$src", [(prefetch addr:$src, (i32 0), (i32 3), (i32 0))]>, TB;
+  def PREFETCHIT1 : I<0x18, MRM6m, (outs), (ins i8mem:$src),
+    "prefetchit1\t$src", [(prefetch addr:$src, (i32 0), (i32 2), (i32 0))]>, TB;
+}
+
+//===----------------------------------------------------------------------===//
 // Pattern fragments to auto generate TBM instructions.
 //===----------------------------------------------------------------------===//
 

diff --git a/llvm/lib/Target/X86/X86Subtarget.h b/llvm/lib/Target/X86/X86Subtarget.h
index cfbf5b9..00458fd 100644 (file)
--- a/llvm/lib/Target/X86/X86Subtarget.h
+++ b/llvm/lib/Target/X86/X86Subtarget.h
@@ -221,7 +221,8 @@ public:
     // We implicitly enable these when we have a write prefix supporting cache
     // level OR if we have prfchw, but don't already have a read prefetch from
     // 3dnow.
-    return hasSSE1() || (hasPRFCHW() && !hasThreeDNow()) || hasPREFETCHWT1();
+    return hasSSE1() || (hasPRFCHW() && !hasThreeDNow()) || hasPREFETCHWT1() ||
+           hasPREFETCHI();
   }
   bool canUseLAHFSAHF() const { return hasLAHFSAHF64() || !is64Bit(); }
   // These are generic getters that OR together all of the thunk types

diff --git a/llvm/test/CodeGen/X86/prefetchi.ll b/llvm/test/CodeGen/X86/prefetchi.ll
new file mode 100644 (file)
index 0000000..8f97e07
--- /dev/null
+++ b/llvm/test/CodeGen/X86/prefetchi.ll
@@ -0,0 +1,21 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-- -mattr=+prefetchi | FileCheck %s
+
+define dso_local void @t(ptr %ptr) nounwind  {
+; CHECK-LABEL: t:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    prefetchit1 (%rdi)
+; CHECK-NEXT:    prefetchit0 (%rdi)
+; CHECK-NEXT:    prefetchit1 t(%rip)
+; CHECK-NEXT:    prefetchit0 ext(%rip)
+; CHECK-NEXT:    retq
+entry:
+  tail call void @llvm.prefetch(ptr %ptr, i32 0, i32 2, i32 0)
+  tail call void @llvm.prefetch(ptr %ptr, i32 0, i32 3, i32 0)
+  tail call void @llvm.prefetch(ptr @t,   i32 0, i32 2, i32 0)
+  tail call void @llvm.prefetch(ptr @ext, i32 0, i32 3, i32 0)
+  ret void
+}
+
+declare dso_local void @ext() nounwind
+declare void @llvm.prefetch(ptr, i32, i32, i32) nounwind

diff --git a/llvm/test/MC/Disassembler/X86/x86-64.txt b/llvm/test/MC/Disassembler/X86/x86-64.txt
index 80e0942..9ea0367 100644 (file)
--- a/llvm/test/MC/Disassembler/X86/x86-64.txt
+++ b/llvm/test/MC/Disassembler/X86/x86-64.txt
@@ -761,3 +761,9 @@
 
 # CHECK: rdpru
 0x0f,0x01,0xfd
+
+# CHECK: prefetchit0 (%rip)
+0x0f,0x18,0x3d,0x00,0x00,0x00,0x00
+
+# CHECK: prefetchit1 (%rip)
+0x0f,0x18,0x35,0x00,0x00,0x00,0x00

diff --git a/llvm/test/MC/X86/PREFETCH-64.s b/llvm/test/MC/X86/PREFETCH-64.s
index 0c4a126..7a10bd1 100644 (file)
--- a/llvm/test/MC/X86/PREFETCH-64.s
+++ b/llvm/test/MC/X86/PREFETCH-64.s
@@ -168,3 +168,50 @@ prefetchwt1 64(%rdx,%rax)
 // CHECK: encoding: [0x0f,0x0d,0x12]        
 prefetchwt1 (%rdx) 
 
+// CHECK: prefetchit0 485498096
+// CHECK: encoding: [0x0f,0x18,0x3c,0x25,0xf0,0x1c,0xf0,0x1c]
+prefetchit0 485498096
+
+// CHECK: prefetchit0 64(%rdx)
+// CHECK: encoding: [0x0f,0x18,0x7a,0x40]
+prefetchit0 64(%rdx)
+
+// CHECK: prefetchit0 64(%rdx,%rax,4)
+// CHECK: encoding: [0x0f,0x18,0x7c,0x82,0x40]
+prefetchit0 64(%rdx,%rax,4)
+
+// CHECK: prefetchit0 -64(%rdx,%rax,4)
+// CHECK: encoding: [0x0f,0x18,0x7c,0x82,0xc0]
+prefetchit0 -64(%rdx,%rax,4)
+
+// CHECK: prefetchit0 64(%rdx,%rax)
+// CHECK: encoding: [0x0f,0x18,0x7c,0x02,0x40]
+prefetchit0 64(%rdx,%rax)
+
+// CHECK: prefetchit0 (%rdx)
+// CHECK: encoding: [0x0f,0x18,0x3a]
+prefetchit0 (%rdx)
+
+// CHECK: prefetchit1 485498096
+// CHECK: encoding: [0x0f,0x18,0x34,0x25,0xf0,0x1c,0xf0,0x1c]
+prefetchit1 485498096
+
+// CHECK: prefetchit1 64(%rdx)
+// CHECK: encoding: [0x0f,0x18,0x72,0x40]
+prefetchit1 64(%rdx)
+
+// CHECK: prefetchit1 64(%rdx,%rax,4)
+// CHECK: encoding: [0x0f,0x18,0x74,0x82,0x40]
+prefetchit1 64(%rdx,%rax,4)
+
+// CHECK: prefetchit1 -64(%rdx,%rax,4)
+// CHECK: encoding: [0x0f,0x18,0x74,0x82,0xc0]
+prefetchit1 -64(%rdx,%rax,4)
+
+// CHECK: prefetchit1 64(%rdx,%rax)
+// CHECK: encoding: [0x0f,0x18,0x74,0x02,0x40]
+prefetchit1 64(%rdx,%rax)
+
+// CHECK: prefetchit1 (%rdx)
+// CHECK: encoding: [0x0f,0x18,0x32]
+prefetchit1 (%rdx)