Fast Math Flag mapping into SDNode

Summary: Adding support for Fast flags in the SDNode to leverage fast math sub flag usage.

Reviewers: spatel, arsenm, jbhateja, hfinkel, escha, qcolombet, echristo, wristow, javed.absar

Reviewed By: spatel

Subscribers: llvm-commits, rampitec, nhaehnle, tstellar, FarhanaAleen, nemanjai, javed.absar, jbhateja, hfinkel, wdng

Differential Revision: https://reviews.llvm.org/D45710

llvm-svn: 331547

3 files changed, 13 insertions, 9 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index d54c6197356..a6a020e8361 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -9542,7 +9542,7 @@ ConstantFoldBITCASTofBUILD_VECTOR(SDNode *BV, EVT DstEltVT) {
 
 static bool isContractable(SDNode *N) {
   SDNodeFlags F = N->getFlags();
-  return F.hasAllowContract() || F.hasUnsafeAlgebra();
+  return F.hasAllowContract() || F.hasAllowReassociation();
 }
 
 /// Try to perform FMA combining on a given FADD node.
@@ -10567,9 +10567,9 @@ SDValue DAGCombiner::visitFMA(SDNode *N) {
     return DAG.getNode(ISD::FMA, SDLoc(N), VT, N1, N0, N2);
 
   // TODO: FMA nodes should have flags that propagate to the created nodes.
-  // For now, create a Flags object for use with all unsafe math transforms.
+  // For now, create a Flags object for use with reassociation math transforms.
   SDNodeFlags Flags;
-  Flags.setUnsafeAlgebra(true);
+  Flags.setAllowReassociation(true);
 
   if (Options.UnsafeFPMath) {
     // (fma x, c1, (fmul x, c2)) -> (fmul x, c1+c2)
@@ -10841,9 +10841,9 @@ SDValue DAGCombiner::visitFSQRT(SDNode *N) {
     return SDValue();
 
   // TODO: FSQRT nodes should have flags that propagate to the created nodes.
-  // For now, create a Flags object for use with all unsafe math transforms.
+  // For now, create a Flags object for use with reassociation math transforms.
   SDNodeFlags Flags;
-  Flags.setUnsafeAlgebra(true);
+  Flags.setAllowReassociation(true);
   return buildSqrtEstimate(N0, Flags);
 }
 
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index bc08e950361..fe4cbfc4bf0 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2776,7 +2776,8 @@ void SelectionDAGBuilder::visitBinary(const User &I, unsigned OpCode) {
   Flags.setNoInfs(FMF.noInfs());
   Flags.setNoNaNs(FMF.noNaNs());
   Flags.setNoSignedZeros(FMF.noSignedZeros());
-  Flags.setUnsafeAlgebra(FMF.isFast());
+  Flags.setApproximateFuncs(FMF.approxFunc());
+  Flags.setAllowReassociation(FMF.allowReassoc());
 
   SDValue BinNodeValue = DAG.getNode(OpCode, getCurSDLoc(), Op1.getValueType(),
                                      Op1, Op2, Flags);
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index 9862bc45b17..cfe8ed01614 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -479,9 +479,6 @@ void SDNode::print_details(raw_ostream &OS, const SelectionDAG *G) const {
   if (getFlags().hasExact())
     OS << " exact";
 
-  if (getFlags().hasUnsafeAlgebra())
-    OS << " unsafe";
-
   if (getFlags().hasNoNaNs())
     OS << " nnan";
 
@@ -497,6 +494,12 @@ void SDNode::print_details(raw_ostream &OS, const SelectionDAG *G) const {
   if (getFlags().hasAllowContract())
     OS << " contract";
 
+  if (getFlags().hasApproximateFuncs())
+    OS << " afn";
+
+  if (getFlags().hasAllowReassociation())
+    OS << " reassoc";
+
   if (getFlags().hasVectorReduction())
     OS << " vector-reduction";