Revert r267098 - [MachineCombiner] Support for floating-point FMA on ARM64

It introduced buildbot failures on clang-cmake-mips, clang-ppc64le-linux, among others.

llvm-svn: 267127
diff --git a/llvm/lib/CodeGen/MachineCombiner.cpp b/llvm/lib/CodeGen/MachineCombiner.cpp
index 6b5c6ba..44601d5 100644
--- a/llvm/lib/CodeGen/MachineCombiner.cpp
+++ b/llvm/lib/CodeGen/MachineCombiner.cpp
@@ -40,7 +40,6 @@
   const TargetRegisterInfo *TRI;
   MCSchedModel SchedModel;
   MachineRegisterInfo *MRI;
-  MachineLoopInfo *MLI; // Current MachineLoopInfo
   MachineTraceMetrics *Traces;
   MachineTraceMetrics::Ensemble *MinInstr;
 
@@ -87,7 +86,6 @@
 
 INITIALIZE_PASS_BEGIN(MachineCombiner, "machine-combiner",
                       "Machine InstCombiner", false, false)
-INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
 INITIALIZE_PASS_DEPENDENCY(MachineTraceMetrics)
 INITIALIZE_PASS_END(MachineCombiner, "machine-combiner", "Machine InstCombiner",
                     false, false)
@@ -95,7 +93,6 @@
 void MachineCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesCFG();
   AU.addPreserved<MachineDominatorTree>();
-  AU.addRequired<MachineLoopInfo>();
   AU.addPreserved<MachineLoopInfo>();
   AU.addRequired<MachineTraceMetrics>();
   AU.addPreserved<MachineTraceMetrics>();
@@ -357,8 +354,6 @@
   DEBUG(dbgs() << "Combining MBB " << MBB->getName() << "\n");
 
   auto BlockIter = MBB->begin();
-  // Check if the block is in a loop.
-  const MachineLoop *ML = MLI->getLoopFor(MBB);
 
   while (BlockIter != MBB->end()) {
     auto &MI = *BlockIter++;
@@ -411,15 +406,11 @@
       if (!NewInstCount)
         continue;
 
-      bool SubstituteAlways = false;
-      if (ML && TII->isThroughputPattern(P))
-        SubstituteAlways = true;
-
       // Substitute when we optimize for codesize and the new sequence has
       // fewer instructions OR
       // the new sequence neither lengthens the critical path nor increases
       // resource pressure.
-      if (SubstituteAlways || doSubstitute(NewInstCount, OldInstCount) ||
+      if (doSubstitute(NewInstCount, OldInstCount) ||
           (improvesCriticalPathLen(MBB, &MI, BlockTrace, InsInstrs,
                                    InstrIdxForVirtReg, P) &&
            preservesResourceLen(MBB, BlockTrace, InsInstrs, DelInstrs))) {
@@ -456,7 +447,6 @@
   SchedModel = STI.getSchedModel();
   TSchedModel.init(SchedModel, &STI, TII);
   MRI = &MF.getRegInfo();
-  MLI = &getAnalysis<MachineLoopInfo>();
   Traces = &getAnalysis<MachineTraceMetrics>();
   MinInstr = nullptr;
   OptSize = MF.getFunction()->optForSize();
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index ff3fee2..6c98008 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -24,7 +24,6 @@
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/SelectionDAGTargetInfo.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
@@ -86,7 +85,6 @@
 
   class DAGCombiner {
     SelectionDAG &DAG;
-    const SelectionDAGTargetInfo &STI;
     const TargetLowering &TLI;
     CombineLevel Level;
     CodeGenOpt::Level OptLevel;
@@ -471,9 +469,8 @@
 
   public:
     DAGCombiner(SelectionDAG &D, AliasAnalysis &A, CodeGenOpt::Level OL)
-        : DAG(D), STI(D.getSelectionDAGInfo()), TLI(D.getTargetLoweringInfo()),
-          Level(BeforeLegalizeTypes), OptLevel(OL), LegalOperations(false),
-          LegalTypes(false), AA(A) {
+        : DAG(D), TLI(D.getTargetLoweringInfo()), Level(BeforeLegalizeTypes),
+          OptLevel(OL), LegalOperations(false), LegalTypes(false), AA(A) {
       ForCodeSize = DAG.getMachineFunction().getFunction()->optForSize();
     }
 
@@ -7718,9 +7715,6 @@
   if (!HasFMAD && !HasFMA)
     return SDValue();
 
-  if (AllowFusion && STI.GenerateFMAsInMachineCombiner(OptLevel))
-    return SDValue();
-
   // Always prefer FMAD to FMA for precision.
   unsigned PreferredFusedOpcode = HasFMAD ? ISD::FMAD : ISD::FMA;
   bool Aggressive = TLI.enableAggressiveFMAFusion(VT);
@@ -7904,9 +7898,6 @@
   if (!HasFMAD && !HasFMA)
     return SDValue();
 
-  if (AllowFusion && STI.GenerateFMAsInMachineCombiner(OptLevel))
-    return SDValue();
-
   // Always prefer FMAD to FMA for precision.
   unsigned PreferredFusedOpcode = HasFMAD ? ISD::FMAD : ISD::FMA;
   bool Aggressive = TLI.enableAggressiveFMAFusion(VT);
diff --git a/llvm/lib/CodeGen/TargetInstrInfo.cpp b/llvm/lib/CodeGen/TargetInstrInfo.cpp
index 800ad6d..86517d9 100644
--- a/llvm/lib/CodeGen/TargetInstrInfo.cpp
+++ b/llvm/lib/CodeGen/TargetInstrInfo.cpp
@@ -655,11 +655,7 @@
 
   return false;
 }
-/// Return true when a code sequence can improve loop throughput.
-bool
-TargetInstrInfo::isThroughputPattern(MachineCombinerPattern Pattern) const {
-  return false;
-}
+
 /// Attempt the reassociation transformation to reduce critical path length.
 /// See the above comments before getMachineCombinerPatterns().
 void TargetInstrInfo::reassociateOps(