Index: include/clang/Basic/TargetInfo.h
===================================================================
--- include/clang/Basic/TargetInfo.h
+++ include/clang/Basic/TargetInfo.h
@@ -72,7 +72,7 @@
   unsigned char LargeArrayMinWidth, LargeArrayAlign;
   unsigned char LongWidth, LongAlign;
   unsigned char LongLongWidth, LongLongAlign;
-  unsigned char SuitableAlign;
+  unsigned short SuitableAlign;
   unsigned char DefaultAlignForAttributeAligned;
   unsigned char MinGlobalAlign;
   unsigned char MaxAtomicPromoteWidth, MaxAtomicInlineWidth;
Index: lib/Basic/Targets/X86.h
===================================================================
--- lib/Basic/Targets/X86.h
+++ lib/Basic/Targets/X86.h
@@ -279,6 +279,7 @@
   X86TargetInfo(const llvm::Triple &Triple, const TargetOptions &)
       : TargetInfo(Triple) {
     LongDoubleFormat = &llvm::APFloat::x87DoubleExtended();
+    SuitableAlign = 128;
   }
   
   unsigned getFloatEvalMethod() const override {
@@ -454,7 +455,6 @@
     DoubleAlign = LongLongAlign = 32;
     LongDoubleWidth = 96;
     LongDoubleAlign = 32;
-    SuitableAlign = 128;
     resetDataLayout("e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128");
     SizeType = UnsignedInt;
     PtrDiffType = SignedInt;
@@ -543,7 +543,6 @@
       : DarwinTargetInfo<X86_32TargetInfo>(Triple, Opts) {
     LongDoubleWidth = 128;
     LongDoubleAlign = 128;
-    SuitableAlign = 128;
     MaxVectorAlign = 256;
     // The watchOS simulator uses the builtin bool type for Objective-C.
     llvm::Triple T = llvm::Triple(Triple);
@@ -722,7 +721,6 @@
     LongDoubleAlign = 128;
     LargeArrayMinWidth = 128;
     LargeArrayAlign = 128;
-    SuitableAlign = 128;
     SizeType = IsX32 ? UnsignedInt : UnsignedLong;
     PtrDiffType = IsX32 ? SignedInt : SignedLong;
     IntPtrType = IsX32 ? SignedInt : SignedLong;
@@ -973,7 +971,6 @@
 public:
   AndroidX86_32TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : LinuxTargetInfo<X86_32TargetInfo>(Triple, Opts) {
-    SuitableAlign = 32;
     LongDoubleWidth = 64;
     LongDoubleFormat = &llvm::APFloat::IEEEdouble();
   }
Index: lib/Basic/Targets/X86.cpp
===================================================================
--- lib/Basic/Targets/X86.cpp
+++ lib/Basic/Targets/X86.cpp
@@ -748,6 +748,13 @@
     return false;
   }
 
+  if (hasFeature("avx512f"))
+      SuitableAlign = std::max(SuitableAlign, (unsigned short)512);
+  else if (hasFeature("avx"))
+      SuitableAlign = std::max(SuitableAlign, (unsigned short)256);
+  else if (hasFeature("sse"))
+      SuitableAlign = std::max(SuitableAlign, (unsigned short)128);
+
   SimdDefaultAlign =
       hasFeature("avx512f") ? 512 : hasFeature("avx") ? 256 : 128;
   return true;
Index: test/CodeGen/builtins-alloca.c
===================================================================
--- /dev/null
+++ test/CodeGen/builtins-alloca.c
@@ -0,0 +1,58 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s | \
+// RUN:   FileCheck %s -check-prefix=CHECK_X86_64
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s -target-feature +avx | \
+// RUN:   FileCheck %s -check-prefix=CHECK_X86_64_AVX
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s -target-feature +avx512f | \
+// RUN:   FileCheck %s -check-prefix=CHECK_X86_64_AVX512
+// RUN: %clang_cc1 -triple i386-unknown-linux-android -emit-llvm -o - %s | \
+// RUN:   FileCheck %s -check-prefix=CHECK_ANDROID_X86_32
+// RUN: %clang_cc1 -triple i386-unknown-linux-android -emit-llvm -o - %s -target-feature +sse | \
+// RUN:   FileCheck %s -check-prefix=CHECK_ANDROID_X86_32_SSE
+// RUN: %clang_cc1 -triple i386-unknown-linux-android -emit-llvm -o - %s -target-feature +avx | \
+// RUN:   FileCheck %s -check-prefix=CHECK_ANDROID_X86_32_AVX
+// RUN: %clang_cc1 -triple i386-unknown-linux-android -emit-llvm -o - %s -target-feature +avx512f | \
+// RUN:   FileCheck %s -check-prefix=CHECK_ANDROID_X86_32_AVX512
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-android -emit-llvm -o - %s | \
+// RUN:   FileCheck %s -check-prefix=CHECK_ANDROID_X86_64
+// RUN: %clang_cc1 -triple i386-unknown-unknown -emit-llvm -o - %s | \
+// RUN:   FileCheck %s -check-prefix=CHECK_I386
+// RUN: %clang_cc1 -triple i386-unknown-unknown -emit-llvm -o - %s -target-feature +avx | \
+// RUN:   FileCheck %s -check-prefix=CHECK_I386_AVX
+// RUN: %clang_cc1 -triple i386-unknown-unknown -emit-llvm -o - %s -target-feature +avx512f | \
+// RUN:   FileCheck %s -check-prefix=CHECK_I386_AVX512
+// RUN: %clang_cc1 -triple i386-apple-darwin -emit-llvm -o - %s |	\
+// RUN:   FileCheck %s -check-prefix=CHECK_I386_APPLE
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -emit-llvm -o - %s | \
+// RUN:   FileCheck %s -check-prefix=CHECK_X86_64_APPLE
+// RUN: %clang_cc1 -triple i386-pc-win32 -emit-llvm -o - %s | \
+// RUN:   FileCheck %s -check-prefix=CHECK_I386_WIN
+// RUN: %clang_cc1 -triple x86_64-unknown-windows -emit-llvm -o - %s | \
+// RUN:   FileCheck %s -check-prefix=CHECK_X86_64_WIN
+// RUN: %clang_cc1 -triple i386-unknown-cygwin -emit-llvm -o - %s | \
+// RUN:   FileCheck %s -check-prefix=CHECK_I386_CYGWIN
+// RUN: %clang_cc1 -triple x86_64-unknown-cygwin -emit-llvm -o - %s | \
+// RUN:   FileCheck %s -check-prefix=CHECK_X86_64_CYGWIN
+
+
+
+char *c1; 
+// CHECK_X86_64: %1 = alloca i8, i64 1, align 16
+// CHECK_X86_64_AVX: %1 = alloca i8, i64 1, align 32
+// CHECK_X86_64_AVX512: %1 = alloca i8, i64 1, align 64
+// CHECK_ANDROID_X86_32: %1 = alloca i8, align 16
+// CHECK_ANDROID_X86_32_SSE: %1 = alloca i8, align 16
+// CHECK_ANDROID_X86_32_AVX: %1 = alloca i8, align 32
+// CHECK_ANDROID_X86_32_AVX512: %1 = alloca i8, align 64
+// CHECK_ANDROID_X86_64: alloca i8, i64 1, align 16
+// CHECK_I386: %1 = alloca i8, align 16
+// CHECK_I386_AVX: %1 = alloca i8, align 32
+// CHECK_I386_AVX512: %1 = alloca i8, align 64
+// CHECK_I386_APPLE: %1 = alloca i8, align 16
+// CHECK_X86_64_APPLE: %1 = alloca i8, i64 1, align 16
+// CHECK_I386_WIN: %1 = alloca i8, align 16
+// CHECK_X86_64_WIN: %1 = alloca i8, i64 1, align 16
+// CHECK_I386_CYGWIN: %1 = alloca i8, align 16
+// CHECK_X86_64_CYGWIN: %1 = alloca i8, i64 1, align 16
+void f1() {
+    c1 = __builtin_alloca(1);
+}