diff --git a/src/librustc/lib/llvm.rs b/src/librustc/lib/llvm.rs
index 9198991e5360e..160f375897b82 100644
--- a/src/librustc/lib/llvm.rs
+++ b/src/librustc/lib/llvm.rs
@@ -1571,13 +1571,15 @@ pub mod llvm {
         pub unsafe fn LLVMBuildAtomicLoad(B: BuilderRef,
                                           PointerVal: ValueRef,
                                           Name: *c_char,
-                                          Order: AtomicOrdering)
+                                          Order: AtomicOrdering,
+                                          Alignment: c_uint)
                                        -> ValueRef;
 
         pub unsafe fn LLVMBuildAtomicStore(B: BuilderRef,
                                            Val: ValueRef,
                                            Ptr: ValueRef,
-                                           Order: AtomicOrdering)
+                                           Order: AtomicOrdering,
+                                           Alignment: c_uint)
                                         -> ValueRef;
 
         pub unsafe fn LLVMBuildAtomicCmpXchg(B: BuilderRef,
diff --git a/src/librustc/middle/trans/build.rs b/src/librustc/middle/trans/build.rs
index 362bcd483b41f..cd914e1072b31 100644
--- a/src/librustc/middle/trans/build.rs
+++ b/src/librustc/middle/trans/build.rs
@@ -14,6 +14,7 @@ use lib::llvm::{Opcode, IntPredicate, RealPredicate, False};
 use lib::llvm::{ValueRef, TypeRef, BasicBlockRef, BuilderRef, ModuleRef};
 use lib;
 use middle::trans::common::*;
+use middle::trans::machine::llalign_of_min;
 use syntax::codemap::span;
 
 use core::hashmap::HashMap;
@@ -544,7 +545,8 @@ pub fn AtomicLoad(cx: block, PointerVal: ValueRef, order: AtomicOrdering) -> Val
             return llvm::LLVMGetUndef(ccx.int_type);
         }
         count_insn(cx, "load.atomic");
-        return llvm::LLVMBuildAtomicLoad(B(cx), PointerVal, noname(), order);
+        let align = llalign_of_min(*ccx, ccx.int_type);
+        return llvm::LLVMBuildAtomicLoad(B(cx), PointerVal, noname(), order, align as c_uint);
     }
 }
 
@@ -558,7 +560,6 @@ pub fn LoadRangeAssert(cx: block, PointerVal: ValueRef, lo: c_ulonglong,
         let min = llvm::LLVMConstInt(t, lo, signed);
         let max = llvm::LLVMConstInt(t, hi, signed);
 
-
         do vec::as_imm_buf([min, max]) |ptr, len| {
             llvm::LLVMSetMetadata(value, lib::llvm::MD_range as c_uint,
                                   llvm::LLVMMDNode(ptr, len as c_uint));
@@ -586,7 +587,8 @@ pub fn AtomicStore(cx: block, Val: ValueRef, Ptr: ValueRef, order: AtomicOrderin
                val_str(cx.ccx().tn, Val),
                val_str(cx.ccx().tn, Ptr));
         count_insn(cx, "store.atomic");
-        llvm::LLVMBuildAtomicStore(B(cx), Val, Ptr, order);
+        let align = llalign_of_min(cx.ccx(), cx.ccx().int_type);
+        llvm::LLVMBuildAtomicStore(B(cx), Val, Ptr, order, align as c_uint);
     }
 }
 
diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index 9e44abe081c95..cff448b6a1a34 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -548,22 +548,24 @@ extern "C" LLVMTypeRef LLVMMetadataType(void) {
 extern "C" LLVMValueRef LLVMBuildAtomicLoad(LLVMBuilderRef B,
                                             LLVMValueRef source,
                                             const char* Name,
-                                            AtomicOrdering order) {
+                                            AtomicOrdering order,
+                                            unsigned alignment) {
     LoadInst* li = new LoadInst(unwrap(source),0);
     li->setVolatile(true);
     li->setAtomic(order);
-    li->setAlignment(sizeof(intptr_t));
+    li->setAlignment(alignment);
     return wrap(unwrap(B)->Insert(li, Name));
 }
 
 extern "C" LLVMValueRef LLVMBuildAtomicStore(LLVMBuilderRef B,
-                                            LLVMValueRef val,
-                                            LLVMValueRef target,
-                                            AtomicOrdering order) {
+                                             LLVMValueRef val,
+                                             LLVMValueRef target,
+                                             AtomicOrdering order,
+                                             unsigned alignment) {
     StoreInst* si = new StoreInst(unwrap(val),unwrap(target));
     si->setVolatile(true);
     si->setAtomic(order);
-    si->setAlignment(sizeof(intptr_t));
+    si->setAlignment(alignment);
     return wrap(unwrap(B)->Insert(si));
 }