[llvm] r346119 - [DAGCombiner] Use tryFoldToZero to simplify some code and make it work correctly between LegalTypes and LegalOperations.

[Craig Topper via llvm-commits]

Author: ctopper
Date: Sun Nov  4 21:53:06 2018
New Revision: 346119

URL: http://llvm.org/viewvc/llvm-project?rev=346119&view=rev
Log:
[DAGCombiner] Use tryFoldToZero to simplify some code and make it work correctly between LegalTypes and LegalOperations.

The original code avoided creating a zero vector after type legalization, but if we're after type legalization the type we have is legal. The real hazard we need to avoid is creating a build vector after op legalization. tryFoldToZero takes care of checking for this.

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=346119&r1=346118&r2=346119&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Sun Nov  4 21:53:06 2018
@@ -3839,10 +3839,7 @@ SDValue DAGCombiner::SimplifyBinOpWithSa
       // Don't try to fold this node if it requires introducing a
       // build vector of all zeros that might be illegal at this stage.
       if (N->getOpcode() == ISD::XOR && !ShOp.isUndef()) {
-        if (!LegalTypes)
-          ShOp = DAG.getConstant(0, SDLoc(N), VT);
-        else
-          ShOp = SDValue();
+        ShOp = tryFoldToZero(SDLoc(N), TLI, VT, DAG, LegalOperations);
       }
 
       // (AND (shuf (A, C), shuf (B, C))) -> shuf (AND (A, B), C)
@@ -3860,10 +3857,7 @@ SDValue DAGCombiner::SimplifyBinOpWithSa
       // build vector of all zeros that might be illegal at this stage.
       ShOp = N0->getOperand(0);
       if (N->getOpcode() == ISD::XOR && !ShOp.isUndef()) {
-        if (!LegalTypes)
-          ShOp = DAG.getConstant(0, SDLoc(N), VT);
-        else
-          ShOp = SDValue();
+        ShOp = tryFoldToZero(SDLoc(N), TLI, VT, DAG, LegalOperations);
       }
 
       // (AND (shuf (C, A), shuf (C, B))) -> shuf (C, AND (A, B))