Index: lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
===================================================================
--- lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
+++ lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
@@ -67,6 +67,22 @@
 
   unsigned getAddressSpaceOperand(Value *I);
 
+  unsigned getAlignment(LoadInst *LI) const {
+    unsigned Align = LI->getAlignment();
+    if (Align != 0)
+      return Align;
+
+    return DL.getABITypeAlignment(LI->getType());
+  }
+
+  unsigned getAlignment(StoreInst *SI) const {
+    unsigned Align = SI->getAlignment();
+    if (Align != 0)
+      return Align;
+
+    return DL.getABITypeAlignment(SI->getValueOperand()->getType());
+  }
+
   /// Checks if it is a consecutive access.
   bool isConsecutiveAccess(Value *A, Value *B);
 
@@ -655,7 +671,7 @@
     });
 
   // Check alignment restrictions.
-  unsigned Alignment = S0->getAlignment();
+  unsigned Alignment = getAlignment(S0);
 
   // If the store is going to be misaligned, don't vectorize it.
   // TODO: Check TLI.allowsMisalignedMemoryAccess
@@ -768,7 +784,7 @@
   }
 
   // Check alignment restrictions.
-  unsigned Alignment = L0->getAlignment();
+  unsigned Alignment = getAlignment(L0);
 
   // If the load is going to be misaligned, don't vectorize it.
   // TODO: Check TLI.allowsMisalignedMemoryAccess
Index: test/Transforms/LoadStoreVectorizer/AMDGPU/merge-stores-private.ll
===================================================================
--- test/Transforms/LoadStoreVectorizer/AMDGPU/merge-stores-private.ll
+++ test/Transforms/LoadStoreVectorizer/AMDGPU/merge-stores-private.ll
@@ -2,6 +2,8 @@
 ; RUN: opt -mtriple=amdgcn-amd-amdhsa -mattr=+max-private-element-size-8 -load-store-vectorizer -S -o - %s | FileCheck -check-prefix=ELT8 -check-prefix=ALL %s
 ; RUN: opt -mtriple=amdgcn-amd-amdhsa -mattr=+max-private-element-size-16 -load-store-vectorizer -S -o - %s | FileCheck -check-prefix=ELT16 -check-prefix=ALL %s
 
+target datalayout = "e-p:32:32-p1:64:64-p2:64:64-p3:32:32-p4:64:64-p5:32:32-p24:64:64-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64"
+
 ; ALL-LABEL: @merge_private_store_4_vector_elts_loads_v4i32
 ; ELT4: store i32
 ; ELT4: store i32
@@ -31,7 +33,7 @@
   %out.gep.2 = getelementptr i8, i8* %out, i32 2
   %out.gep.3 = getelementptr i8, i8* %out, i32 3
 
-  store i8 9, i8* %out
+  store i8 9, i8* %out, align 4
   store i8 1, i8* %out.gep.1
   store i8 23, i8* %out.gep.2
   store i8 19, i8* %out.gep.3
@@ -43,7 +45,7 @@
 define void @merge_private_store_4_vector_elts_loads_v2i16(i16* %out) #0 {
   %out.gep.1 = getelementptr i16, i16* %out, i32 1
 
-  store i16 9, i16* %out
+  store i16 9, i16* %out, align 4
   store i16 12, i16* %out.gep.1
   ret void
 }
Index: test/Transforms/LoadStoreVectorizer/AMDGPU/merge-stores.ll
===================================================================
--- test/Transforms/LoadStoreVectorizer/AMDGPU/merge-stores.ll
+++ test/Transforms/LoadStoreVectorizer/AMDGPU/merge-stores.ll
@@ -1,6 +1,8 @@
 ; RUN: opt -mtriple=amdgcn-amd-amdhsa -load-store-vectorizer -S -o - %s | FileCheck %s
 ; Copy of test/CodeGen/AMDGPU/merge-stores.ll with some additions
 
+target datalayout = "e-p:32:32-p1:64:64-p2:64:64-p3:32:32-p4:64:64-p5:32:32-p24:64:64-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64"
+
 ; TODO: Vector element tests
 ; TODO: Non-zero base offset for load and store combinations
 ; TODO: Same base addrspacecasted
@@ -17,7 +19,8 @@
 }
 
 ; CHECK-LABEL: @merge_global_store_2_constants_i8_natural_align
-; CHECK: store <2 x i8> <i8 -56, i8 123>, <2 x i8> addrspace(1)* %{{[0-9]+$}}
+; CHECK: store i8
+; CHECK: store i8
 define void @merge_global_store_2_constants_i8_natural_align(i8 addrspace(1)* %out) #0 {
   %out.gep.1 = getelementptr i8, i8 addrspace(1)* %out, i32 1
 
@@ -47,7 +50,8 @@
 }
 
 ; CHECK-LABEL: @merge_global_store_2_constants_i16_natural_align
-; CHECK: store <2 x i16> <i16 456, i16 123>, <2 x i16> addrspace(1)* %{{[0-9]+$}}
+; CHECK: store i16
+; CHECK: store i16
 define void @merge_global_store_2_constants_i16_natural_align(i16 addrspace(1)* %out) #0 {
   %out.gep.1 = getelementptr i16, i16 addrspace(1)* %out, i32 1
 
@@ -57,7 +61,8 @@
 }
 
 ; CHECK-LABEL: @merge_global_store_2_constants_half_natural_align
-; CHECK: store <2 x half> <half 0xH3C00, half 0xH4000>, <2 x half> addrspace(1)* %{{[0-9]+$}}
+; CHECK: store half
+; CHECK: store half
 define void @merge_global_store_2_constants_half_natural_align(half addrspace(1)* %out) #0 {
   %out.gep.1 = getelementptr half, half addrspace(1)* %out, i32 1
 
@@ -67,7 +72,7 @@
 }
 
 ; CHECK-LABEL: @merge_global_store_2_constants_i32
-; CHECK: store <2 x i32> <i32 456, i32 123>, <2 x i32> addrspace(1)* %{{[0-9]+$}}
+; CHECK: store <2 x i32> <i32 456, i32 123>, <2 x i32> addrspace(1)* %{{[0-9]+}}, align 4
 define void @merge_global_store_2_constants_i32(i32 addrspace(1)* %out) #0 {
   %out.gep.1 = getelementptr i32, i32 addrspace(1)* %out, i32 1
 
@@ -77,7 +82,7 @@
 }
 
 ; CHECK-LABEL: @merge_global_store_2_constants_i32_f32
-; CHECK: store <2 x i32> <i32 456, i32 1065353216>, <2 x i32> addrspace(1)* %{{[0-9]+$}}
+; CHECK: store <2 x i32> <i32 456, i32 1065353216>, <2 x i32> addrspace(1)* %{{[0-9]+}}, align 4
 define void @merge_global_store_2_constants_i32_f32(i32 addrspace(1)* %out) #0 {
   %out.gep.1 = getelementptr i32, i32 addrspace(1)* %out, i32 1
   %out.gep.1.bc = bitcast i32 addrspace(1)* %out.gep.1 to float addrspace(1)*
@@ -97,7 +102,7 @@
 }
 
 ; CHECK-LABEL: @merge_global_store_4_constants_i32
-; CHECK: store <4 x i32> <i32 1234, i32 123, i32 456, i32 333>, <4 x i32> addrspace(1)* %{{[0-9]+$}}
+; CHECK: store <4 x i32> <i32 1234, i32 123, i32 456, i32 333>, <4 x i32> addrspace(1)* %{{[0-9]+}}, align 4
 define void @merge_global_store_4_constants_i32(i32 addrspace(1)* %out) #0 {
   %out.gep.1 = getelementptr i32, i32 addrspace(1)* %out, i32 1
   %out.gep.2 = getelementptr i32, i32 addrspace(1)* %out, i32 2
@@ -126,7 +131,7 @@
 
 ; First store is out of order.
 ; CHECK-LABEL: @merge_global_store_4_constants_f32
-; CHECK: store <4 x float> <float 8.000000e+00, float 1.000000e+00, float 2.000000e+00, float 4.000000e+00>, <4 x float> addrspace(1)* %{{[0-9]+$}}
+; CHECK: store <4 x float> <float 8.000000e+00, float 1.000000e+00, float 2.000000e+00, float 4.000000e+00>, <4 x float> addrspace(1)* %{{[0-9]+}}, align 4
 define void @merge_global_store_4_constants_f32(float addrspace(1)* %out) #0 {
   %out.gep.1 = getelementptr float, float addrspace(1)* %out, i32 1
   %out.gep.2 = getelementptr float, float addrspace(1)* %out, i32 2
@@ -140,7 +145,7 @@
 }
 
 ; CHECK-LABEL: @merge_global_store_4_constants_mixed_i32_f32
-; CHECK: store <4 x float> <float 8.000000e+00, float 0x36D6000000000000, float 2.000000e+00, float 0x36E1000000000000>, <4 x float> addrspace(1)* %{{[0-9]+}}
+; CHECK: store <4 x float> <float 8.000000e+00, float 0x36D6000000000000, float 2.000000e+00, float 0x36E1000000000000>, <4 x float> addrspace(1)* %{{[0-9]+}}, align 4
 define void @merge_global_store_4_constants_mixed_i32_f32(float addrspace(1)* %out) #0 {
   %out.gep.1 = getelementptr float, float addrspace(1)* %out, i32 1
   %out.gep.2 = getelementptr float, float addrspace(1)* %out, i32 2
@@ -157,7 +162,7 @@
 }
 
 ; CHECK-LABEL: @merge_global_store_3_constants_i32
-; CHECK: store <3 x i32> <i32 1234, i32 123, i32 456>, <3 x i32> addrspace(1)* %{{[0-9]+$}}
+; CHECK: store <3 x i32> <i32 1234, i32 123, i32 456>, <3 x i32> addrspace(1)* %{{[0-9]+}}, align 4
 define void @merge_global_store_3_constants_i32(i32 addrspace(1)* %out) #0 {
   %out.gep.1 = getelementptr i32, i32 addrspace(1)* %out, i32 1
   %out.gep.2 = getelementptr i32, i32 addrspace(1)* %out, i32 2
@@ -169,7 +174,7 @@
 }
 
 ; CHECK-LABEL: @merge_global_store_2_constants_i64
-; CHECK: store <2 x i64> <i64 456, i64 123>, <2 x i64> addrspace(1)* %{{[0-9]+$}}
+; CHECK: store <2 x i64> <i64 456, i64 123>, <2 x i64> addrspace(1)* %{{[0-9]+}}, align 8
 define void @merge_global_store_2_constants_i64(i64 addrspace(1)* %out) #0 {
   %out.gep.1 = getelementptr i64, i64 addrspace(1)* %out, i64 1
 
@@ -179,8 +184,8 @@
 }
 
 ; CHECK-LABEL: @merge_global_store_4_constants_i64
-; CHECK: store <2 x i64> <i64 456, i64 333>, <2 x i64> addrspace(1)* %{{[0-9]+$}}
-; CHECK: store <2 x i64> <i64 1234, i64 123>, <2 x i64> addrspace(1)* %{{[0-9]+$}}
+; CHECK: store <2 x i64> <i64 456, i64 333>, <2 x i64> addrspace(1)* %{{[0-9]+}}, align 8
+; CHECK: store <2 x i64> <i64 1234, i64 123>, <2 x i64> addrspace(1)* %{{[0-9]+}}, align 8
 define void @merge_global_store_4_constants_i64(i64 addrspace(1)* %out) #0 {
   %out.gep.1 = getelementptr i64, i64 addrspace(1)* %out, i64 1
   %out.gep.2 = getelementptr i64, i64 addrspace(1)* %out, i64 2
@@ -427,8 +432,14 @@
 }
 
 ; CHECK-LABEL: @merge_global_store_4_adjacent_loads_i8_natural_align
-; CHECK: load <4 x i8>
-; CHECK: store <4 x i8>
+; CHECK: load i8
+; CHECK: load i8
+; CHECK: load i8
+; CHECK: load i8
+; CHECK: store i8
+; CHECK: store i8
+; CHECK: store i8
+; CHECK: store i8
 define void @merge_global_store_4_adjacent_loads_i8_natural_align(i8 addrspace(1)* %out, i8 addrspace(1)* %in) #0 {
   %out.gep.1 = getelementptr i8, i8 addrspace(1)* %out, i8 1
   %out.gep.2 = getelementptr i8, i8 addrspace(1)* %out, i8 2
@@ -481,7 +492,7 @@
 }
 
 ; CHECK-LABEL: @merge_local_store_2_constants_i32
-; CHECK: store <2 x i32> <i32 456, i32 123>, <2 x i32> addrspace(3)* %{{[0-9]+$}}
+; CHECK: store <2 x i32> <i32 456, i32 123>, <2 x i32> addrspace(3)* %{{[0-9]+}}, align 4
 define void @merge_local_store_2_constants_i32(i32 addrspace(3)* %out) #0 {
   %out.gep.1 = getelementptr i32, i32 addrspace(3)* %out, i32 1
 
Index: test/Transforms/LoadStoreVectorizer/AMDGPU/missing-alignment.ll
===================================================================
--- /dev/null
+++ test/Transforms/LoadStoreVectorizer/AMDGPU/missing-alignment.ll
@@ -0,0 +1,30 @@
+; RUN: opt -mtriple=amdgcn-- -load-store-vectorizer -S -o - %s | FileCheck %s
+
+@lds = internal addrspace(3) global [512 x float] undef, align 4
+
+; The original load has an implicit alignment of 4, and should not
+; increase to an align 8 load.
+
+; CHECK-LABEL: @load_keep_base_alignment_missing_align(
+; CHECK: load <2 x float>, <2 x float> addrspace(3)* %{{[0-9]+}}, align 4
+define void @load_keep_base_alignment_missing_align(float addrspace(1)* %out) {
+  %ptr0 = getelementptr inbounds [512 x float], [512 x float] addrspace(3)* @lds, i32 0, i32 11
+  %val0 = load float, float addrspace(3)* %ptr0
+
+  %ptr1 = getelementptr inbounds [512 x float], [512 x float] addrspace(3)* @lds, i32 0, i32 12
+  %val1 = load float, float addrspace(3)* %ptr1
+  %add = fadd float %val0, %val1
+  store float %add, float addrspace(1)* %out
+  ret void
+}
+
+
+; CHECK-LABEL: @store_keep_base_alignment_missing_align(
+; CHECK: store <2 x float> zeroinitializer, <2 x float> addrspace(3)* %{{[0-9]+}}, align 4
+define void @store_keep_base_alignment_missing_align() {
+  %arrayidx0 = getelementptr inbounds [512 x float], [512 x float] addrspace(3)* @lds, i32 0, i32 1
+  %arrayidx1 = getelementptr inbounds [512 x float], [512 x float] addrspace(3)* @lds, i32 0, i32 2
+  store float 0.0, float addrspace(3)* %arrayidx0
+  store float 0.0, float addrspace(3)* %arrayidx1
+  ret void
+}