Index: lib/AST/RecordLayoutBuilder.cpp
===================================================================
--- lib/AST/RecordLayoutBuilder.cpp
+++ lib/AST/RecordLayoutBuilder.cpp
@@ -1552,7 +1552,8 @@
     FieldAlign = 1;
 
   // But, if there's an 'aligned' attribute on the field, honor that.
-  if (unsigned ExplicitFieldAlign = D->getMaxAlignment()) {
+  unsigned ExplicitFieldAlign = D->getMaxAlignment();
+  if (ExplicitFieldAlign) {
     FieldAlign = std::max(FieldAlign, ExplicitFieldAlign);
     UnpackedFieldAlign = std::max(UnpackedFieldAlign, ExplicitFieldAlign);
   }
@@ -1601,7 +1602,8 @@
         (AllowPadding &&
          (FieldOffset & (FieldAlign-1)) + FieldSize > TypeSize)) {
       FieldOffset = llvm::RoundUpToAlignment(FieldOffset, FieldAlign);
-    }
+    } else if (ExplicitFieldAlign)
+      FieldOffset = llvm::RoundUpToAlignment(FieldOffset, ExplicitFieldAlign);
 
     // Repeat the computation for diagnostic purposes.
     if (FieldSize == 0 ||
@@ -1609,6 +1611,9 @@
          (UnpackedFieldOffset & (UnpackedFieldAlign-1)) + FieldSize > TypeSize))
       UnpackedFieldOffset = llvm::RoundUpToAlignment(UnpackedFieldOffset,
                                                      UnpackedFieldAlign);
+    else if (ExplicitFieldAlign)
+      UnpackedFieldOffset = llvm::RoundUpToAlignment(UnpackedFieldOffset,
+                                                     ExplicitFieldAlign);
   }
 
   // If we're using external layout, give the external layout a chance
Index: test/Sema/bitfield-layout.c
===================================================================
--- test/Sema/bitfield-layout.c
+++ test/Sema/bitfield-layout.c
@@ -1,13 +1,25 @@
 // RUN: %clang_cc1 %s -fsyntax-only -verify -triple=i686-apple-darwin9
+// RUN: %clang_cc1 %s -fsyntax-only -verify -triple=arm
+// RUN: %clang_cc1 %s -fsyntax-only -verify -triple=aarch64
 // expected-no-diagnostics
+#include <stddef.h>
 
-#define CHECK_SIZE(kind, name, size) extern int name##1[sizeof(kind name) == size ? 1 : -1];
-#define CHECK_ALIGN(kind, name, size) extern int name##2[__alignof(kind name) == size ? 1 : -1];
+#define CHECK_SIZE(kind, name, size) \
+  extern int name##_1[sizeof(kind name) == size ? 1 : -1];
+#define CHECK_ALIGN(kind, name, size) \
+  extern int name##_2[__alignof(kind name) == size ? 1 : -1];
+#define CHECK_OFFSET(kind, name, member, offset) \
+  extern int name##_3[offsetof(kind name, member) == offset ? 1 : -1];
 
 // Zero-width bit-fields
 struct a {char x; int : 0; char y;};
+#if defined(__arm__) || defined(__aarch64__)
+CHECK_SIZE(struct, a, 8)
+CHECK_ALIGN(struct, a, 4)
+#else
 CHECK_SIZE(struct, a, 5)
 CHECK_ALIGN(struct, a, 1)
+#endif
 
 // Zero-width bit-fields with packed
 struct __attribute__((packed)) a2 { short x : 9; char : 0; int y : 17; };
@@ -16,8 +28,13 @@
 
 // Zero-width bit-fields at the end of packed struct
 struct __attribute__((packed)) a3 { short x : 9; int : 0; };
+#if defined(__arm__) || defined(__aarch64__)
+CHECK_SIZE(struct, a3, 4)
+CHECK_ALIGN(struct, a3, 4)
+#else
 CHECK_SIZE(struct, a3, 4)
 CHECK_ALIGN(struct, a3, 1)
+#endif
 
 // For comparison, non-zero-width bit-fields at the end of packed struct
 struct __attribute__((packed)) a4 { short x : 9; int : 1; };
@@ -25,17 +42,32 @@
 CHECK_ALIGN(struct, a4, 1)
 
 union b {char x; int : 0; char y;};
+#if defined(__arm__) || defined(__aarch64__)
+CHECK_SIZE(union, b, 4)
+CHECK_ALIGN(union, b, 4)
+#else
 CHECK_SIZE(union, b, 1)
 CHECK_ALIGN(union, b, 1)
+#endif
 
 // Unnamed bit-field align
 struct c {char x; int : 20;};
+#if defined(__arm__) || defined(__aarch64__)
+CHECK_SIZE(struct, c, 4)
+CHECK_ALIGN(struct, c, 4)
+#else
 CHECK_SIZE(struct, c, 4)
 CHECK_ALIGN(struct, c, 1)
+#endif
 
 union d {char x; int : 20;};
+#if defined(__arm__) || defined(__aarch64__)
+CHECK_SIZE(union, d, 4)
+CHECK_ALIGN(union, d, 4)
+#else
 CHECK_SIZE(union, d, 3)
 CHECK_ALIGN(union, d, 1)
+#endif
 
 // Bit-field packing
 struct __attribute__((packed)) e {int x : 4, y : 30, z : 30;};
@@ -56,3 +88,153 @@
 CHECK_SIZE(struct, s0, 0x32100008)
 CHECK_ALIGN(struct, s0, 4)
 
+// Bit-field with explicit align bigger than normal.
+struct g0 {
+  char a;
+  __attribute__((aligned(16))) int b : 1;
+  char c;
+};
+
+CHECK_SIZE(struct, g0, 32);
+CHECK_ALIGN(struct, g0, 16);
+CHECK_OFFSET(struct, g0, c, 17);
+
+// Bit-field with explicit align smaller than normal.
+struct g1 {
+  char a;
+  __attribute__((aligned(2))) int b : 1;
+  char c;
+};
+
+CHECK_SIZE(struct, g1, 4);
+CHECK_ALIGN(struct, g1, 4);
+CHECK_OFFSET(struct, g1, c, 3);
+
+// Same as above but without explicit align.
+struct g2 {
+  char a;
+  int b : 1;
+  char c;
+};
+
+CHECK_SIZE(struct, g2, 4);
+CHECK_ALIGN(struct, g2, 4);
+CHECK_OFFSET(struct, g2, c, 2);
+
+// Explicit attribute align on bit-field has precedence over packed attribute
+// applied too the struct.
+struct __attribute__((packed)) g3 {
+  char a;
+  __attribute__((aligned(16))) int b : 1;
+  char c;
+};
+
+CHECK_SIZE(struct, g3, 32);
+CHECK_ALIGN(struct, g3, 16);
+CHECK_OFFSET(struct, g3, c, 17);
+
+struct __attribute__((packed)) g4 {
+  char a;
+  __attribute__((aligned(2))) int b : 1;
+  char c;
+};
+
+CHECK_SIZE(struct, g4, 4);
+CHECK_ALIGN(struct, g4, 2);
+CHECK_OFFSET(struct, g4, c, 3);
+
+struct g5 {
+  char : 1;
+  __attribute__((aligned(1))) int n : 24;
+};
+CHECK_SIZE(struct, g5, 4);
+CHECK_ALIGN(struct, g5, 4);
+
+struct __attribute__((packed)) g6 {
+  char : 1;
+  __attribute__((aligned(1))) int n : 24;
+};
+CHECK_SIZE(struct, g6, 4);
+CHECK_ALIGN(struct, g6, 1);
+
+struct g7 {
+  char : 1;
+  __attribute__((aligned(1))) int n : 25;
+};
+CHECK_SIZE(struct, g7, 8);
+CHECK_ALIGN(struct, g7, 4);
+
+struct __attribute__((packed)) g8 {
+  char : 1;
+  __attribute__((aligned(1))) int n : 25;
+};
+CHECK_SIZE(struct, g8, 5);
+CHECK_ALIGN(struct, g8, 1);
+
+struct g9 {
+  __attribute__((aligned(1))) char a : 2, b : 2, c : 2, d : 2, e : 2;
+  int i;
+};
+CHECK_SIZE(struct, g9, 12);
+CHECK_ALIGN(struct, g9, 4);
+
+struct __attribute__((packed)) g10 {
+  __attribute__((aligned(1))) char a : 2, b : 2, c : 2, d : 2, e : 2;
+  int i;
+};
+CHECK_SIZE(struct, g10, 9);
+CHECK_ALIGN(struct, g10, 1);
+
+struct g11 {
+  char a;
+  __attribute__((aligned(1))) long long b : 62;
+  char c;
+};
+#if  defined(__arm__) || defined(__aarch64__)
+CHECK_SIZE(struct, g11, 24);
+CHECK_ALIGN(struct, g11, 8);
+CHECK_OFFSET(struct, g11, c, 16);
+#else
+CHECK_SIZE(struct, g11, 16);
+CHECK_ALIGN(struct, g11, 4);
+CHECK_OFFSET(struct, g11, c, 12);
+#endif
+
+struct __attribute__((packed)) g12 {
+  char a;
+  __attribute__((aligned(1))) long long b : 62;
+  char c;
+};
+CHECK_SIZE(struct, g12, 10);
+CHECK_ALIGN(struct, g12, 1);
+CHECK_OFFSET(struct, g12, c, 9);
+
+struct g13 {
+  char a;
+  __attribute__((aligned(1))) long long : 0;
+  char c;
+};
+#if  defined(__arm__) || defined(__aarch64__)
+CHECK_SIZE(struct, g13, 16);
+CHECK_ALIGN(struct, g13, 8);
+CHECK_OFFSET(struct, g13, c, 8);
+#else
+CHECK_SIZE(struct, g13, 5);
+CHECK_ALIGN(struct, g13, 1);
+CHECK_OFFSET(struct, g13, c, 4);
+#endif
+
+struct __attribute__((packed)) g14 {
+  char a;
+  __attribute__((aligned(1))) long long : 0;
+  char c;
+};
+#if  defined(__arm__) || defined(__aarch64__)
+CHECK_SIZE(struct, g14, 16);
+CHECK_ALIGN(struct, g14, 8);
+CHECK_OFFSET(struct, g14, c, 8);
+#else
+CHECK_SIZE(struct, g14, 5);
+CHECK_ALIGN(struct, g14, 1);
+CHECK_OFFSET(struct, g14, c, 4);
+#endif