[llvm] r346728 - [DAGCombiner] Enable tryToFoldExtendOfConstant to run after legalize vector ops

[Craig Topper via llvm-commits]

Author: ctopper
Date: Mon Nov 12 17:59:32 2018
New Revision: 346728

URL: http://llvm.org/viewvc/llvm-project?rev=346728&view=rev
Log:
[DAGCombiner] Enable tryToFoldExtendOfConstant to run after legalize vector ops

It should be ok to create a new build_vector after legal operations so long as it doesn't cause an infinite loop in DAG combiner.

Unfortunately, X86's custom constant folding in combineVSZext is hiding any test changes from this. But I'm trying to get to a point where that X86 specific code isn't necessary at all.

Differential Revision: https://reviews.llvm.org/D54285

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=346728&r1=346727&r2=346728&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Mon Nov 12 17:59:32 2018
@@ -8023,8 +8023,7 @@ SDValue DAGCombiner::visitSETCCCARRY(SDN
 /// Vector extends are not folded if operations are legal; this is to
 /// avoid introducing illegal build_vector dag nodes.
 static SDValue tryToFoldExtendOfConstant(SDNode *N, const TargetLowering &TLI,
-                                         SelectionDAG &DAG, bool LegalTypes,
-                                         bool LegalOperations) {
+                                         SelectionDAG &DAG, bool LegalTypes) {
   unsigned Opcode = N->getOpcode();
   SDValue N0 = N->getOperand(0);
   EVT VT = N->getValueType(0);
@@ -8044,8 +8043,7 @@ static SDValue tryToFoldExtendOfConstant
   // fold (zext (build_vector AllConstants) -> (build_vector AllConstants)
   // fold (aext (build_vector AllConstants) -> (build_vector AllConstants)
   EVT SVT = VT.getScalarType();
-  if (!(VT.isVector() &&
-      (!LegalTypes || (!LegalOperations && TLI.isTypeLegal(SVT))) &&
+  if (!(VT.isVector() && (!LegalTypes || TLI.isTypeLegal(SVT)) &&
       ISD::isBuildVectorOfConstantSDNodes(N0.getNode())))
     return SDValue();
 
@@ -8479,8 +8477,7 @@ SDValue DAGCombiner::visitSIGN_EXTEND(SD
   EVT VT = N->getValueType(0);
   SDLoc DL(N);
 
-  if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes,
-                                              LegalOperations))
+  if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes))
     return Res;
 
   // fold (sext (sext x)) -> (sext x)
@@ -8718,8 +8715,7 @@ SDValue DAGCombiner::visitZERO_EXTEND(SD
   SDValue N0 = N->getOperand(0);
   EVT VT = N->getValueType(0);
 
-  if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes,
-                                              LegalOperations))
+  if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes))
     return Res;
 
   // fold (zext (zext x)) -> (zext x)
@@ -8968,8 +8964,7 @@ SDValue DAGCombiner::visitANY_EXTEND(SDN
   SDValue N0 = N->getOperand(0);
   EVT VT = N->getValueType(0);
 
-  if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes,
-                                              LegalOperations))
+  if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes))
     return Res;
 
   // fold (aext (aext x)) -> (aext x)
@@ -9495,8 +9490,7 @@ SDValue DAGCombiner::visitSIGN_EXTEND_VE
   if (N0.isUndef())
     return DAG.getUNDEF(VT);
 
-  if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes,
-                                              LegalOperations))
+  if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes))
     return Res;
 
   return SDValue();
@@ -9509,8 +9503,7 @@ SDValue DAGCombiner::visitZERO_EXTEND_VE
   if (N0.isUndef())
     return DAG.getUNDEF(VT);
 
-  if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes,
-                                              LegalOperations))
+  if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes))
     return Res;
 
   return SDValue();