Index: lib/CodeGen/SelectionDAG/LegalizeDAG.cpp =================================================================== --- lib/CodeGen/SelectionDAG/LegalizeDAG.cpp +++ lib/CodeGen/SelectionDAG/LegalizeDAG.cpp @@ -1192,8 +1192,11 @@ // If the index is dependent on the store we will introduce a cycle when // creating the load (the load uses the index, and by replacing the chain - // we will make the index dependent on the load). - if (SDNode::hasPredecessorHelper(ST, Visited, Worklist)) + // we will make the index dependent on the load). Also, the store might be + // dependent on the extractelement and introduce a cycle when creating + // the load. + if (SDNode::hasPredecessorHelper(ST, Visited, Worklist) || + ST->hasPredecessor(Op.getNode())) continue; StackPtr = ST->getBasePtr(); Index: test/CodeGen/X86/pr30562.ll =================================================================== --- /dev/null +++ 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> [ , %entry ], [ , %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 + +} +