diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index 076b04bf342c..11af4708428e 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -2249,7 +2249,9 @@ public:
   bool handleTargetFeatures(std::vector<std::string> &Features,
                             DiagnosticsEngine &Diags) override;
   StringRef getABI() const override {
-    if (getTriple().getArch() == llvm::Triple::x86_64 && SSELevel >= AVX)
+    if (getTriple().getArch() == llvm::Triple::x86_64 && SSELevel >= AVX512F)
+      return "avx512";
+    else if (getTriple().getArch() == llvm::Triple::x86_64 && SSELevel >= AVX)
       return "avx";
     else if (getTriple().getArch() == llvm::Triple::x86 &&
              MMX3DNowLevel == NoMMX3DNow)
diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index ed8f10d7848e..d4d0e7870961 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -1394,12 +1394,15 @@ namespace {
 /// The AVX ABI level for X86 targets.
 enum class X86AVXABILevel {
   None,
-  AVX
+  AVX,
+  AVX512
 };
 
 /// \p returns the size in bits of the largest (native) vector for \p AVXLevel.
 static unsigned getNativeVectorSizeForAVXABI(X86AVXABILevel AVXLevel) {
   switch (AVXLevel) {
+  case X86AVXABILevel::AVX512:
+    return 512;
   case X86AVXABILevel::AVX:
     return 256;
   case X86AVXABILevel::None:
@@ -1956,6 +1959,9 @@ void X86_64ABIInfo::classify(QualType Ty, uint64_t OffsetBase,
       // Note that per 3.5.7 of AMD64-ABI, 256-bit args are only passed in
       // registers if they are "named", i.e. not part of the "..." of a
       // variadic function.
+      //
+      // Similarly, per 3.2.3. of the AVX512 draft, 512-bits ("named") args are
+      // split into eight eightbyte chunks, one SSE and seven SSEUP.
       Lo = SSE;
       Hi = SSEUp;
     }
@@ -7211,7 +7217,8 @@ const TargetCodeGenInfo &CodeGenModule::getTargetCodeGenInfo() {
 
   case llvm::Triple::x86_64: {
     StringRef ABI = getTarget().getABI();
-    X86AVXABILevel AVXLevel = (ABI == "avx" ? X86AVXABILevel::AVX :
+    X86AVXABILevel AVXLevel = (ABI == "avx512" ? X86AVXABILevel::AVX512 :
+                               ABI == "avx" ? X86AVXABILevel::AVX :
                                X86AVXABILevel::None);
 
     switch (Triple.getOS()) {
diff --git a/clang/test/CodeGen/x86_64-arguments.c b/clang/test/CodeGen/x86_64-arguments.c
index c412e3c06e86..bb9fba190262 100644
--- a/clang/test/CodeGen/x86_64-arguments.c
+++ b/clang/test/CodeGen/x86_64-arguments.c
@@ -1,7 +1,9 @@
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s | \
-// RUN:   FileCheck %s -check-prefix=CHECK -check-prefix=SSE
+// RUN:   FileCheck %s -check-prefix=CHECK -check-prefix=SSE -check-prefix=NO-AVX512
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s -target-feature +avx | \
-// RUN:   FileCheck %s -check-prefix=CHECK -check-prefix=AVX
+// RUN:   FileCheck %s -check-prefix=CHECK -check-prefix=AVX -check-prefix=NO-AVX512
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s -target-feature +avx512f | \
+// RUN:   FileCheck %s -check-prefix=CHECK -check-prefix=AVX -check-prefix=AVX512
 #include <stdarg.h>
 
 // CHECK-LABEL: define signext i8 @f0()
@@ -458,3 +460,77 @@ void test54() {
 }
 // AVX: @test54_helper(<8 x float> {{%[a-zA-Z0-9]+}}, <8 x float> {{%[a-zA-Z0-9]+}}, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double {{%[a-zA-Z0-9]+}}, double {{%[a-zA-Z0-9]+}})
 // AVX: @test54_helper(<8 x float> {{%[a-zA-Z0-9]+}}, <8 x float> {{%[a-zA-Z0-9]+}}, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, { double, double }* byval align 8 {{%[a-zA-Z0-9]+}})
+
+typedef float __m512 __attribute__ ((__vector_size__ (64)));
+typedef struct {
+  __m512 m;
+} s512;
+
+s512 x55;
+__m512 x56;
+
+// Even on AVX512, aggregates of size larger than four eightbytes have class
+// MEMORY (AVX512 draft 0.3 3.2.3p2 Rule 1).
+//
+// CHECK: declare void @f55(%struct.s512* byval align 64)
+void f55(s512 x);
+
+// However, __m512 has type SSE/SSEUP on AVX512.
+//
+// AVX512: declare void @f56(<16 x float>)
+// NO-AVX512: declare void @f56(<16 x float>* byval align 64)
+void f56(__m512 x);
+void f57() { f55(x55); f56(x56); }
+
+// Like for __m128 on AVX, check that the struct below is passed
+// in the same way regardless of AVX512 being used.
+//
+// CHECK: declare void @f58(%struct.t256* byval align 32)
+typedef struct t256 {
+  __m256 m;
+  __m256 n;
+} two256;
+
+extern void f58(two256 s);
+void f59(two256 s) {
+  f58(s);
+}
+
+// CHECK: declare void @f60(%struct.sat256* byval align 32)
+typedef struct at256 {
+  __m256 array[2];
+} Atwo256;
+typedef struct sat256 {
+  Atwo256 x;
+} SAtwo256;
+
+extern void f60(SAtwo256 s);
+void f61(SAtwo256 s) {
+  f60(s);
+}
+
+// AVX512: @f62_helper(i32 0, <16 x float> {{%[a-zA-Z0-9]+}}, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double {{%[a-zA-Z0-9]+}}, double {{%[a-zA-Z0-9]+}})
+void f62_helper(int, ...);
+__m512 x62;
+void f62() {
+  f62_helper(0, x62, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0i);
+}
+
+// Like for __m256 on AVX, we always pass __m512 in memory, and don't
+// need to use the register save area.
+//
+// AVX512-LABEL: define void @f63
+// AVX512-NOT: br i1
+// AVX512: ret void
+void f63(__m512 *m, __builtin_va_list argList) {
+  *m = __builtin_va_arg(argList, __m512);
+}
+
+// AVX512: @f64_helper(<16 x float> {{%[a-zA-Z0-9]+}}, <16 x float> {{%[a-zA-Z0-9]+}}, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double {{%[a-zA-Z0-9]+}}, double {{%[a-zA-Z0-9]+}})
+// AVX512: @f64_helper(<16 x float> {{%[a-zA-Z0-9]+}}, <16 x float> {{%[a-zA-Z0-9]+}}, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, { double, double }* byval align 8 {{%[a-zA-Z0-9]+}})
+void f64_helper(__m512, ...);
+__m512 x64;
+void f64() {
+  f64_helper(x64, x64, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0i);
+  f64_helper(x64, x64, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0i);
+}
diff --git a/clang/test/OpenMP/simd_metadata.c b/clang/test/OpenMP/simd_metadata.c
index 2a95fef160f4..e7e35dd54d74 100644
--- a/clang/test/OpenMP/simd_metadata.c
+++ b/clang/test/OpenMP/simd_metadata.c
@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 -fopenmp -triple x86_64-unknown-unknown -emit-llvm %s -o - | FileCheck %s -check-prefix=CHECK -check-prefix=X86
 // RUN: %clang_cc1 -fopenmp -triple x86_64-unknown-unknown -target-feature +avx -emit-llvm %s -o - | FileCheck %s -check-prefix=CHECK -check-prefix=X86-AVX
+// RUN: %clang_cc1 -fopenmp -triple x86_64-unknown-unknown -target-feature +avx512f -emit-llvm %s -o - | FileCheck %s -check-prefix=CHECK -check-prefix=X86-AVX512
 // RUN: %clang_cc1 -fopenmp -triple powerpc64-unknown-unknown -emit-llvm %s -o - | FileCheck %s -check-prefix=CHECK -check-prefix=PPC
 // RUN: %clang_cc1 -fopenmp -triple powerpc64-unknown-unknown -target-abi elfv1-qpx -emit-llvm %s -o - | FileCheck %s -check-prefix=CHECK -check-prefix=PPC-QPX
 
@@ -16,6 +17,7 @@ void h1(float *c, float *a, double b[], int size)
 
 // X86-NEXT:     [[A_MASKEDPTR:%.+]] = and i{{[0-9]+}} [[A_PTRINT]], 15
 // X86-AVX-NEXT: [[A_MASKEDPTR:%.+]] = and i{{[0-9]+}} [[A_PTRINT]], 31
+// X86-AVX512-NEXT: [[A_MASKEDPTR:%.+]] = and i{{[0-9]+}} [[A_PTRINT]], 63
 // PPC-NEXT:     [[A_MASKEDPTR:%.+]] = and i{{[0-9]+}} [[A_PTRINT]], 15
 // PPC-QPX-NEXT: [[A_MASKEDPTR:%.+]] = and i{{[0-9]+}} [[A_PTRINT]], 15
 
@@ -25,6 +27,7 @@ void h1(float *c, float *a, double b[], int size)
 
 // X86-NEXT:      [[B_MASKEDPTR:%.+]] = and i{{[0-9]+}} [[B_PTRINT]], 15
 // X86-AVX-NEXT:  [[B_MASKEDPTR:%.+]] = and i{{[0-9]+}} [[B_PTRINT]], 31
+// X86-AVX512-NEXT: [[B_MASKEDPTR:%.+]] = and i{{[0-9]+}} [[B_PTRINT]], 63
 // PPC-NEXT:      [[B_MASKEDPTR:%.+]] = and i{{[0-9]+}} [[B_PTRINT]], 15
 // PPC-QPX-NEXT:  [[B_MASKEDPTR:%.+]] = and i{{[0-9]+}} [[B_PTRINT]], 31