Index: polly/trunk/lib/CodeGen/BlockGenerators.cpp
===================================================================
--- polly/trunk/lib/CodeGen/BlockGenerators.cpp
+++ polly/trunk/lib/CodeGen/BlockGenerators.cpp
@@ -595,7 +595,10 @@
 
   // If the condition is a tautology, don't generate a condition around the
   // code.
-  if (StmtDom.is_subset(Subdomain)) {
+  bool IsPartialWrite =
+      !StmtDom.intersect_params(give(Stmt.getParent()->getContext()))
+           .is_subset(Subdomain);
+  if (!IsPartialWrite) {
     GenThenFunc();
     return;
   }
Index: polly/trunk/test/Isl/CodeGen/partial_write_full_write_that_appears_partial.ll
===================================================================
--- polly/trunk/test/Isl/CodeGen/partial_write_full_write_that_appears_partial.ll
+++ polly/trunk/test/Isl/CodeGen/partial_write_full_write_that_appears_partial.ll
@@ -0,0 +1,34 @@
+; RUN: opt %loadPolly -polly-codegen -S < %s | FileCheck %s
+
+; CHECK:      polly.stmt.if.then81:                             ; preds = %polly.stmt.if.end75
+; CHECK-NEXT:   %scevgep = getelementptr [2 x %S], [2 x %S]* %tmp, i64 0, i64 %.147
+; CHECK-NEXT:   %scevgep1 = bitcast %S* %scevgep to float*
+; CHECK-NEXT:   store float undef, float* %scevgep1, align 4, !alias.scope !0, !noalias !2
+; CHECK-NEXT:   br label %polly.stmt.if.end87.region_exiting
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64--linux-android"
+
+%S = type { float, float }
+
+define void @f() {
+entry:
+  %tmp = alloca [2 x %S], align 4
+  %cmp52 = fcmp olt float undef, undef
+  %not.cmp52 = xor i1 %cmp52, true
+  %.147 = zext i1 %not.cmp52 to i64
+  %fX64 = getelementptr inbounds [2 x %S], [2 x %S]* %tmp, i64 0, i64 %.147, i32 0
+  br label %if.end75
+
+if.end75:
+  %cmp80 = fcmp olt float undef, undef
+  br i1 %cmp80, label %if.then81, label %if.end87
+
+if.then81:
+  store float undef, float* %fX64, align 4
+  br label %if.end87
+
+if.end87:
+  %0 = phi float [ undef, %if.then81 ], [ undef, %if.end75 ]
+  ret void
+}