Index: cfe/trunk/lib/CodeGen/TargetInfo.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/TargetInfo.cpp
+++ cfe/trunk/lib/CodeGen/TargetInfo.cpp
@@ -3790,17 +3790,18 @@
     Address RegAddrHi =
       CGF.Builder.CreateConstInBoundsByteGEP(RegAddrLo,
                                              CharUnits::fromQuantity(16));
-    llvm::Type *DoubleTy = CGF.DoubleTy;
-    llvm::StructType *ST = llvm::StructType::get(DoubleTy, DoubleTy);
+    llvm::Type *ST = AI.canHaveCoerceToType()
+                         ? AI.getCoerceToType()
+                         : llvm::StructType::get(CGF.DoubleTy, CGF.DoubleTy);
     llvm::Value *V;
     Address Tmp = CGF.CreateMemTemp(Ty);
     Tmp = CGF.Builder.CreateElementBitCast(Tmp, ST);
-    V = CGF.Builder.CreateLoad(
-                   CGF.Builder.CreateElementBitCast(RegAddrLo, DoubleTy));
+    V = CGF.Builder.CreateLoad(CGF.Builder.CreateElementBitCast(
+        RegAddrLo, ST->getStructElementType(0)));
     CGF.Builder.CreateStore(V,
                    CGF.Builder.CreateStructGEP(Tmp, 0, CharUnits::Zero()));
-    V = CGF.Builder.CreateLoad(
-                   CGF.Builder.CreateElementBitCast(RegAddrHi, DoubleTy));
+    V = CGF.Builder.CreateLoad(CGF.Builder.CreateElementBitCast(
+        RegAddrHi, ST->getStructElementType(1)));
     CGF.Builder.CreateStore(V,
           CGF.Builder.CreateStructGEP(Tmp, 1, CharUnits::fromQuantity(8)));
 
Index: cfe/trunk/test/CodeGen/x86_64-floatvectors.c
===================================================================
--- cfe/trunk/test/CodeGen/x86_64-floatvectors.c
+++ cfe/trunk/test/CodeGen/x86_64-floatvectors.c
@@ -0,0 +1,131 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s | \
+// RUN:   FileCheck %s
+
+// This test validates that the inreg branch generation for __builtin_va_arg 
+// does not exceed the alloca size of the type, which can cause the SROA pass to
+// eliminate the assignment.
+
+typedef struct { float x, y, z; } vec3f;
+
+double Vec3FTest(__builtin_va_list ap) {
+  vec3f vec = __builtin_va_arg(ap, vec3f);
+  return vec.x + vec.y + vec.z;
+}
+// CHECK: define double @Vec3FTest
+// CHECK: vaarg.in_reg:
+// CHECK: [[Vec3FLoad1:%.*]] = load <2 x float>, <2 x float>*
+// CHECK: [[Vec3FGEP1:%.*]] = getelementptr inbounds { <2 x float>, float }, { <2 x float>, float }* {{%.*}}, i32 0, i32 0
+// CHECK: store <2 x float> [[Vec3FLoad1]], <2 x float>* [[Vec3FGEP1]]
+// CHECK: [[Vec3FLoad2:%.*]] = load float, float*
+// CHECK: [[Vec3FGEP2:%.*]] = getelementptr inbounds { <2 x float>, float }, { <2 x float>, float }* {{%.*}}, i32 0, i32 1
+// CHECK: store float [[Vec3FLoad2]], float* [[Vec3FGEP2]]
+// CHECK: vaarg.in_mem:
+
+
+typedef struct { float x, y, z, q; } vec4f;
+
+double Vec4FTest(__builtin_va_list ap) {
+  vec4f vec = __builtin_va_arg(ap, vec4f);
+  return vec.x + vec.y + vec.z + vec.q;
+}
+// CHECK: define double @Vec4FTest
+// CHECK: vaarg.in_reg:
+// CHECK: [[Vec4FLoad1:%.*]] = load <2 x float>, <2 x float>*
+// CHECK: [[Vec4FGEP1:%.*]] = getelementptr inbounds { <2 x float>, <2 x float> }, { <2 x float>, <2 x float> }* {{%.*}}, i32 0, i32 0
+// CHECK: store <2 x float> [[Vec4FLoad1]], <2 x float>* [[Vec4FGEP1]]
+// CHECK: [[Vec4FLoad2:%.*]] = load <2 x float>, <2 x float>*
+// CHECK: [[Vec4FGEP2:%.*]] = getelementptr inbounds { <2 x float>, <2 x float> }, { <2 x float>, <2 x float> }* {{%.*}}, i32 0, i32 1
+// CHECK: store <2 x float> [[Vec4FLoad2]], <2 x float>* [[Vec4FGEP2]]
+// CHECK: vaarg.in_mem:
+
+typedef struct { double x, y; } vec2d;
+
+double Vec2DTest(__builtin_va_list ap) {
+  vec2d vec = __builtin_va_arg(ap, vec2d);
+  return vec.x + vec.y;
+}
+// CHECK: define double @Vec2DTest
+// CHECK: vaarg.in_reg:
+// CHECK: [[Vec2DLoad1:%.*]] = load double, double*
+// CHECK: [[Vec2DGEP1:%.*]] = getelementptr inbounds { double, double }, { double, double }* {{%.*}}, i32 0, i32 0
+// CHECK: store double [[Vec2DLoad1]], double* [[Vec2DGEP1]]
+// CHECK: [[Vec2DLoad2:%.*]] = load double, double*
+// CHECK: [[Vec2DGEP2:%.*]] = getelementptr inbounds { double, double }, { double, double }* {{%.*}}, i32 0, i32 1
+// CHECK: store double [[Vec2DLoad2]], double* [[Vec2DGEP2]]
+// CHECK: vaarg.in_mem:
+
+typedef struct {
+  float x, y;
+  double z;
+} vec2f1d;
+
+double Vec2F1DTest(__builtin_va_list ap) {
+  vec2f1d vec = __builtin_va_arg(ap, vec2f1d);
+  return vec.x + vec.y + vec.z;
+}
+// CHECK: define double @Vec2F1DTest
+// CHECK: vaarg.in_reg:
+// CHECK: [[Vec2F1DLoad1:%.*]] = load <2 x float>, <2 x float>*
+// CHECK: [[Vec2F1DGEP1:%.*]] = getelementptr inbounds { <2 x float>, double }, { <2 x float>, double }* {{%.*}}, i32 0, i32 0
+// CHECK: store <2 x float> [[Vec2F1DLoad1]], <2 x float>* [[Vec2F1DGEP1]]
+// CHECK: [[Vec2F1DLoad2:%.*]] = load double, double*
+// CHECK: [[Vec2F1DGEP2:%.*]] = getelementptr inbounds { <2 x float>, double }, { <2 x float>, double }* {{%.*}}, i32 0, i32 1
+// CHECK: store double [[Vec2F1DLoad2]], double* [[Vec2F1DGEP2]]
+// CHECK: vaarg.in_mem:
+
+typedef struct {
+  double x;
+  float y, z;
+} vec1d2f;
+
+double Vec1D2FTest(__builtin_va_list ap) {
+  vec1d2f vec = __builtin_va_arg(ap, vec1d2f);
+  return vec.x + vec.y + vec.z;
+}
+// CHECK: define double @Vec1D2FTest
+// CHECK: vaarg.in_reg:
+// CHECK: [[Vec1D2FLoad1:%.*]] = load double, double*
+// CHECK: [[Vec1D2FGEP1:%.*]] = getelementptr inbounds { double, <2 x float> }, { double, <2 x float> }* {{%.*}}, i32 0, i32 0
+// CHECK: store double [[Vec1D2FLoad1]], double* [[Vec1D2FGEP1]]
+// CHECK: [[Vec1D2FLoad2:%.*]] = load <2 x float>, <2 x float>*
+// CHECK: [[Vec1D2FGEP2:%.*]] = getelementptr inbounds { double, <2 x float> }, { double, <2 x float> }* {{%.*}}, i32 0, i32 1
+// CHECK: store <2 x float> [[Vec1D2FLoad2]], <2 x float>* [[Vec1D2FGEP2]]
+// CHECK: vaarg.in_mem:
+
+typedef struct {
+  float x;
+  double z;
+} vec1f1d;
+
+double Vec1F1DTest(__builtin_va_list ap) {
+  vec1f1d vec = __builtin_va_arg(ap, vec1f1d);
+  return vec.x  + vec.z;
+}
+// CHECK: define double @Vec1F1DTest
+// CHECK: vaarg.in_reg:
+// CHECK: [[Vec1F1DLoad1:%.*]] = load float, float*
+// CHECK: [[Vec1F1DGEP1:%.*]] = getelementptr inbounds { float, double }, { float, double }* {{%.*}}, i32 0, i32 0
+// CHECK: store float [[Vec1F1DLoad1]], float* [[Vec1F1DGEP1]]
+// CHECK: [[Vec1F1DLoad2:%.*]] = load double, double*
+// CHECK: [[Vec1F1DGEP2:%.*]] = getelementptr inbounds { float, double }, { float, double }* {{%.*}}, i32 0, i32 1
+// CHECK: store double [[Vec1F1DLoad2]], double* [[Vec1F1DGEP2]]
+// CHECK: vaarg.in_mem:
+
+typedef struct {
+  double x;
+  float z;
+} vec1d1f;
+
+double Vec1D1FTest(__builtin_va_list ap) {
+  vec1d1f vec = __builtin_va_arg(ap, vec1d1f);
+  return vec.x  + vec.z;
+}
+// CHECK: define double @Vec1D1FTest
+// CHECK: vaarg.in_reg:
+// CHECK: [[Vec1D1FLoad1:%.*]] = load double, double*
+// CHECK: [[Vec1D1FGEP1:%.*]] = getelementptr inbounds { double, float }, { double, float }* {{%.*}}, i32 0, i32 0
+// CHECK: store double [[Vec1D1FLoad1]], double* [[Vec1D1FGEP1]]
+// CHECK: [[Vec1D1FLoad2:%.*]] = load float, float*
+// CHECK: [[Vec1D1FGEP2:%.*]] = getelementptr inbounds { double, float }, { double, float }* {{%.*}}, i32 0, i32 1
+// CHECK: store float [[Vec1D1FLoad2]], float* [[Vec1D1FGEP2]]
+// CHECK: vaarg.in_mem: