Be careful not to optimize a SELECT_CC into a SETCC post-legalization if the SETCC node would be illegal.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167344 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 27 insertions, 23 deletions

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index a83203b663..5416a5c1d7 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -9412,34 +9412,38 @@ SDValue DAGCombiner::SimplifySelectCC(DebugLoc DL, SDValue N0, SDValue N1,
       return SDValue();
 
     // Get a SetCC of the condition
-    // FIXME: Should probably make sure that setcc is legal if we ever have a
-    // target where it isn't.
-    SDValue Temp, SCC;
-    // cast from setcc result type to select result type
-    if (LegalTypes) {
-      SCC  = DAG.getSetCC(DL, TLI.getSetCCResultType(N0.getValueType()),
-                          N0, N1, CC);
-      if (N2.getValueType().bitsLT(SCC.getValueType()))
-        Temp = DAG.getZeroExtendInReg(SCC, N2.getDebugLoc(), N2.getValueType());
-      else
+    // NOTE: Don't create a SETCC if it's not legal on this target.
+    if (!LegalOperations ||
+        TLI.isOperationLegal(ISD::SETCC,
+          LegalTypes ? TLI.getSetCCResultType(N0.getValueType()) : MVT::i1)) {
+      SDValue Temp, SCC;
+      // cast from setcc result type to select result type
+      if (LegalTypes) {
+        SCC  = DAG.getSetCC(DL, TLI.getSetCCResultType(N0.getValueType()),
+                            N0, N1, CC);
+        if (N2.getValueType().bitsLT(SCC.getValueType()))
+          Temp = DAG.getZeroExtendInReg(SCC, N2.getDebugLoc(),
+                                        N2.getValueType());
+        else
+          Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(),
+                             N2.getValueType(), SCC);
+      } else {
+        SCC  = DAG.getSetCC(N0.getDebugLoc(), MVT::i1, N0, N1, CC);
         Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(),
                            N2.getValueType(), SCC);
-    } else {
-      SCC  = DAG.getSetCC(N0.getDebugLoc(), MVT::i1, N0, N1, CC);
-      Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(),
-                         N2.getValueType(), SCC);
-    }
+      }
 
-    AddToWorkList(SCC.getNode());
-    AddToWorkList(Temp.getNode());
+      AddToWorkList(SCC.getNode());
+      AddToWorkList(Temp.getNode());
 
-    if (N2C->getAPIntValue() == 1)
-      return Temp;
+      if (N2C->getAPIntValue() == 1)
+        return Temp;
 
-    // shl setcc result by log2 n2c
-    return DAG.getNode(ISD::SHL, DL, N2.getValueType(), Temp,
-                       DAG.getConstant(N2C->getAPIntValue().logBase2(),
-                                       getShiftAmountTy(Temp.getValueType())));
+      // shl setcc result by log2 n2c
+      return DAG.getNode(ISD::SHL, DL, N2.getValueType(), Temp,
+                         DAG.getConstant(N2C->getAPIntValue().logBase2(),
+                                         getShiftAmountTy(Temp.getValueType())));
+    }
   }
 
   // Check to see if this is the equivalent of setcc