Index: llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -345,6 +345,11 @@
   if (!SI->isSimple())
     return false;
 
+  // Don't convert stores of non-integral pointer types to memsets (which stores
+  // integers).
+  if (DL->isNonIntegralPointerType(SI->getValueOperand()->getType()))
+    return false;
+
   // Avoid merging nontemporal stores.
   if (SI->getMetadata(LLVMContext::MD_nontemporal))
     return false;
Index: llvm/trunk/test/Transforms/LoopIdiom/non-integral-pointers.ll
===================================================================
--- llvm/trunk/test/Transforms/LoopIdiom/non-integral-pointers.ll
+++ llvm/trunk/test/Transforms/LoopIdiom/non-integral-pointers.ll
@@ -0,0 +1,48 @@
+; RUN: opt -S -basicaa -loop-idiom < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128-ni:4"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @f_0(i8 addrspace(3)** %ptr) {
+; CHECK-LABEL: @f_0(
+; CHECK: call{{.*}}memset
+
+; LIR'ing stores of pointers with address space 3 is fine, since
+; they're integral pointers.
+
+entry:
+  br label %for.body
+
+for.body:
+  %indvar = phi i64 [ 0, %entry ], [ %indvar.next, %for.body ]
+  %arrayidx = getelementptr i8 addrspace(3)*, i8 addrspace(3)** %ptr, i64 %indvar
+  store i8 addrspace(3)* null, i8 addrspace(3)** %arrayidx, align 4
+  %indvar.next = add i64 %indvar, 1
+  %exitcond = icmp eq i64 %indvar.next, 10000
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
+
+define void @f_1(i8 addrspace(4)** %ptr) {
+; CHECK-LABEL: @f_1(
+; CHECK-NOT: call{{.*}}memset
+
+; LIR'ing stores of pointers with address space 4 is not ok, since
+; they're non-integral pointers.
+
+entry:
+  br label %for.body
+
+for.body:
+  %indvar = phi i64 [ 0, %entry ], [ %indvar.next, %for.body ]
+  %arrayidx = getelementptr i8 addrspace(4)*, i8 addrspace(4)** %ptr, i64 %indvar
+  store i8 addrspace(4)* null, i8 addrspace(4)** %arrayidx, align 4
+  %indvar.next = add i64 %indvar, 1
+  %exitcond = icmp eq i64 %indvar.next, 10000
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}