diff --git a/llvm/lib/Target/X86/X86.td b/llvm/lib/Target/X86/X86.td
--- a/llvm/lib/Target/X86/X86.td
+++ b/llvm/lib/Target/X86/X86.td
@@ -551,7 +551,8 @@
                                                   FeatureSlow3OpsLEA,
                                                   FeatureFastScalarFSQRT,
                                                   FeatureFastSHLDRotate,
-                                                  FeatureMergeToThreeWayBranch];
+                                                  FeatureMergeToThreeWayBranch,
+                                                  FeatureFast15ByteNOP];
   list<SubtargetFeature> SNBSpecificFeatures = [FeatureSlowUAMem32,
                                                 FeaturePOPCNTFalseDeps];
   list<SubtargetFeature> SNBInheritableFeatures =
diff --git a/llvm/test/CodeGen/X86/align-branch-boundary-suppressions.ll b/llvm/test/CodeGen/X86/align-branch-boundary-suppressions.ll
--- a/llvm/test/CodeGen/X86/align-branch-boundary-suppressions.ll
+++ b/llvm/test/CodeGen/X86/align-branch-boundary-suppressions.ll
@@ -69,8 +69,12 @@
 ; CHECK-NEXT:    .cfi_def_cfa_register %rbp
 ; CHECK-NEXT:    #noautopadding
 ; CHECK-NEXT:  .Ltmp2:
+; CHECK-NEXT:    .byte 102
+; CHECK-NEXT:    .byte 102
+; CHECK-NEXT:    .byte 102
+; CHECK-NEXT:    .byte 102
+; CHECK-NEXT:    .byte 102
 ; CHECK-NEXT:    nopw %cs:512(%rax,%rax)
-; CHECK-NEXT:    nopl 8(%rax,%rax)
 ; CHECK-NEXT:    #autopadding
 ; CHECK-NEXT:    popq %rbp
 ; CHECK-NEXT:    .cfi_def_cfa %rsp, 8
diff --git a/llvm/test/MC/X86/align-via-relaxation.s b/llvm/test/MC/X86/align-via-relaxation.s
--- a/llvm/test/MC/X86/align-via-relaxation.s
+++ b/llvm/test/MC/X86/align-via-relaxation.s
@@ -32,8 +32,7 @@
   # that would require a further round of relaxation
   # CHECK: <bar>:
   # CHECK: 22: eb fe                          jmp -2 <bar>
-  # CHECK: 24: 66 2e 0f 1f 84 00 00 00 00 00  nopw %cs:(%rax,%rax)
-  # CHECK: 2e: 66 90                          nop
+  # CHECK: 24: 66 66 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:(%rax,%rax)
   # CHECK: 30: 0f 0b                          ud2
 
 bar:  
@@ -48,8 +47,8 @@
   # CHECK: <loop_preheader>:
   # CHECK: 45: 48 85 c0                       testq %rax, %rax
   # CHECK: 48: 0f 8e 22 00 00 00              jle 34 <loop_exit>
-  # CHECK: 4e: 66 2e 0f 1f 84 00 00 00 00 00  nopw %cs:(%rax,%rax)
-  # CHECK: 58: 0f 1f 84 00 00 00 00 00        nopl (%rax,%rax)
+  # CHECK: 4e: 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:(%rax,%rax)
+  # CHECK: 5d: 0f 1f 00                       nopl (%rax)
   # CHECK: <loop_header>:
   # CHECK: 60: 48 83 e8 01                    subq $1, %rax
   # CHECK: 64: 48 85 c0                       testq %rax, %rax
diff --git a/llvm/test/MC/X86/x86_long_nop.s b/llvm/test/MC/X86/x86_long_nop.s
--- a/llvm/test/MC/X86/x86_long_nop.s
+++ b/llvm/test/MC/X86/x86_long_nop.s
@@ -17,12 +17,12 @@
 # RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu %s -mcpu=znver2 | llvm-objdump -d -no-show-raw-insn - | FileCheck %s --check-prefix=LNOP15
 # RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=nehalem %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP10 %s
 # RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=westmere %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP10 %s
-# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=sandybridge %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP10 %s
-# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=ivybridge %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP10 %s
-# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=haswell %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP10 %s
-# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=broadwell %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP10 %s
-# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=skylake %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP10 %s
-# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=skx %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP10 %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=sandybridge %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP15 %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=ivybridge %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP15 %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=haswell %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP15 %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=broadwell %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP15 %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=skylake %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP15 %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=skx %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP15 %s
 # RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=knl %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP10 %s
 # RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=knm %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=LNOP10 %s