From: Sanjay Patel <spatel@rotateright.com>
Date: Thu, 23 May 2019 20:17:25 +0000 (+0000)
Subject: [DAGCombiner] make folds of binops safe for opcodes that produce >1 value
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=52cdffd499b79297749382c4da6ce9b5866f397b;p=llvm

[DAGCombiner] make folds of binops safe for opcodes that produce >1 value

This is no-functional-change-intended currently because the definition
of isBinOp() only includes opcodes that produce 1 value. But if we
share that implementation with isCommutativeBinOp() as proposed in
D62191, then we need to make sure that the callers bail out for
opcodes that they are not prepared to handle correctly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361547 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 0aa481ff2e2..b5bb86580fb 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1968,7 +1968,8 @@ static ConstantSDNode *getAsNonOpaqueConstant(SDValue N) {
 }
 
 SDValue DAGCombiner::foldBinOpIntoSelect(SDNode *BO) {
-  assert(TLI.isBinOp(BO->getOpcode()) && "Unexpected binary operator");
+  assert(TLI.isBinOp(BO->getOpcode()) && BO->getNumValues() == 1 &&
+         "Unexpected binary operator");
 
   // Don't do this unless the old select is going away. We want to eliminate the
   // binary operator, not replace a binop with a select.
@@ -16172,7 +16173,8 @@ static SDValue scalarizeExtractedBinop(SDNode *ExtElt, SelectionDAG &DAG,
   SDValue Vec = ExtElt->getOperand(0);
   SDValue Index = ExtElt->getOperand(1);
   auto *IndexC = dyn_cast<ConstantSDNode>(Index);
-  if (!IndexC || !TLI.isBinOp(Vec.getOpcode()) || !Vec.hasOneUse())
+  if (!IndexC || !TLI.isBinOp(Vec.getOpcode()) || !Vec.hasOneUse() ||
+      Vec.getNode()->getNumValues() != 1)
     return SDValue();
 
   // Targets may want to avoid this to prevent an expensive register transfer.
@@ -17412,7 +17414,7 @@ static SDValue narrowInsertExtractVectorBinOp(SDNode *Extract,
                                               SelectionDAG &DAG) {
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   SDValue BinOp = Extract->getOperand(0);
-  if (!TLI.isBinOp(BinOp.getOpcode()))
+  if (!TLI.isBinOp(BinOp.getOpcode()) || BinOp.getNode()->getNumValues() != 1)
     return SDValue();
 
   SDValue Bop0 = BinOp.getOperand(0), Bop1 = BinOp.getOperand(1);
@@ -17456,7 +17458,7 @@ static SDValue narrowExtractedVectorBinOp(SDNode *Extract, SelectionDAG &DAG) {
   // feeding an extract subvector.
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   SDValue BinOp = peekThroughBitcasts(Extract->getOperand(0));
-  if (!TLI.isBinOp(BinOp.getOpcode()))
+  if (!TLI.isBinOp(BinOp.getOpcode()) || BinOp.getNode()->getNumValues() != 1)
     return SDValue();
 
   // The binop must be a vector type, so we can extract some fraction of it.
@@ -18268,7 +18270,7 @@ SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) {
   if (SVN->isSplat() && SVN->getSplatIndex() < (int)NumElts) {
     int SplatIndex = SVN->getSplatIndex();
     if (TLI.isExtractVecEltCheap(VT, SplatIndex) &&
-        TLI.isBinOp(N0.getOpcode())) {
+        TLI.isBinOp(N0.getOpcode()) && N0.getNode()->getNumValues() == 1) {
       // splat (vector_bo L, R), Index -->
       // splat (scalar_bo (extelt L, Index), (extelt R, Index))
       SDValue L = N0.getOperand(0), R = N0.getOperand(1);