Index: lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1197,6 +1197,15 @@
         continue;
 
       StackPtr = ST->getBasePtr();
+
+      // Another check to make sure that the index could not introduce a cycle
+      // while creating the load.
+      Visited.clear();
+      Worklist.clear();
+      Worklist.push_back(StackPtr.getNode());
+      if (SDNode::hasPredecessorHelper(Idx.getNode(), Visited, Worklist))
+        continue;
+
       Ch = SDValue(ST, 0);
       break;
     }
Index: test/CodeGen/X86/pr30562.ll
===================================================================
--- test/CodeGen/X86/pr30562.ll
+++ test/CodeGen/X86/pr30562.ll
@@ -0,0 +1,22 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s
+
+define i32 @foo(i64* nocapture %perm, i32 %n) {
+entry:
+  br label %body
+
+body:
+; CHECK-LABEL: foo:
+; CHECK: pslldq  $8, %xmm0
+  %vec.ind = phi <2 x i64> [ <i64 0, i64 1>, %entry ], [ <i64 2, i64 3>, %body ]
+  %l13 = extractelement <2 x i64> %vec.ind, i32 %n
+  %l14 = getelementptr inbounds i64, i64* %perm, i64 %l13
+  %l15 = bitcast i64* %l14 to <2 x i64>*
+  store <2 x i64> %vec.ind, <2 x i64>* %l15, align 8
+  %niter.ncmp.3 = icmp eq i64 %l13, 0
+  br i1 %niter.ncmp.3, label %exit, label %body
+
+exit:
+  ret i32 %n
+
+}
+