Pull in r203311 from upstream llvm trunk (by Arnold Schwaighofer):

  ISel: Make VSELECT selection terminate in cases where the condition type has to
  be split and the result type widened.

  When the condition of a vselect has to be split it makes no sense widening the
  vselect and thereby widening the condition. We end up in an endless loop of
  widening (vselect result type) and splitting (condition mask type) doing this.
  Instead, split both the condition and the vselect and widen the result.

  I ran this over the test suite with i686 and mattr=+sse and saw no regressions.

  Fixes PR18036.

With this fix the original problem case from the graphics/rawtherapee
port (posted in http://llvm.org/PR18036 ) now compiles within ~97MB RSS.

Reported by:	mandree
MFC after:	1 week

1 files changed, 11 insertions, 0 deletions

diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index f7a3e3d25067..5f4ff7533619 100644
--- a/contrib/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/contrib/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -2180,6 +2180,17 @@ SDValue DAGTypeLegalizer::WidenVecRes_SELECT(SDNode *N) {
     if (getTypeAction(CondVT) == TargetLowering::TypeWidenVector)
       Cond1 = GetWidenedVector(Cond1);
 
+    // If we have to split the condition there is no point in widening the
+    // select. This would result in an cycle of widening the select ->
+    // widening the condition operand -> splitting the condition operand ->
+    // splitting the select -> widening the select. Instead split this select
+    // further and widen the resulting type.
+    if (getTypeAction(CondVT) == TargetLowering::TypeSplitVector) {
+      SDValue SplitSelect = SplitVecOp_VSELECT(N, 0);
+      SDValue Res = ModifyToType(SplitSelect, WidenVT);
+      return Res;
+    }
+
     if (Cond1.getValueType() != CondWidenVT)
       Cond1 = ModifyToType(Cond1, CondWidenVT);
   }