diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/TargetLowering.cpp | 3 | ||||
| -rw-r--r-- | test/CodeGen/X86/2011-01-10-DagCombineHang.ll | 15 |
2 files changed, 17 insertions, 1 deletions
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp index 396ebc15c6..f9e0992ea1 100644 --- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -1176,8 +1176,9 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op, // the RHS. if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(Op.getOperand(1))) { APInt LHSZero, LHSOne; + // Do not increment Depth here; that can cause an infinite loop. TLO.DAG.ComputeMaskedBits(Op.getOperand(0), NewMask, - LHSZero, LHSOne, Depth+1); + LHSZero, LHSOne, Depth); // If the LHS already has zeros where RHSC does, this and is dead. if ((LHSZero & NewMask) == (~RHSC->getAPIntValue() & NewMask)) return TLO.CombineTo(Op, Op.getOperand(0)); diff --git a/test/CodeGen/X86/2011-01-10-DagCombineHang.ll b/test/CodeGen/X86/2011-01-10-DagCombineHang.ll new file mode 100644 index 0000000000..bf438b82ed --- /dev/null +++ b/test/CodeGen/X86/2011-01-10-DagCombineHang.ll @@ -0,0 +1,15 @@ +; RUN: llc < %s -mtriple=x86_64-apple-darwin10 +; This formerly got DagCombine into a loop, PR 8916. + +define i32 @foo(i64 %x, i64 %y, i64 %z, i32 %a, i32 %b) { +entry: + %"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0] + %t1 = shl i64 %x, 15 + %t2 = and i64 %t1, 4294934528 + %t3 = or i64 %t2, %y + %t4 = xor i64 %z, %t3 + %t5 = trunc i64 %t4 to i32 + %t6 = add i32 %a, %t5 + %t7 = add i32 %t6, %b + ret i32 %t7 +} |