Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)

[oota-llvm.git] / lib / CodeGen / BranchFolding.cpp

diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index 42bf9343c99ca667789a41f56d2fa30809fb9f37..60e8b52dff83e5866b72a2d54ef10135649f09b7 100644 (file)
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -79,7 +79,7 @@ namespace {
       MachineFunctionPass::getAnalysisUsage(AU);
     }
   };
-} // namespace
+}
 
 char BranchFolderPass::ID = 0;
 char &llvm::BranchFolderPassID = BranchFolderPass::ID;
@@ -264,14 +264,59 @@ bool BranchFolder::OptimizeFunction(MachineFunction &MF,
 //  Tail Merging of Blocks
 //===----------------------------------------------------------------------===//
 
+/// HashMachineInstr - Compute a hash value for MI and its operands.
+static unsigned HashMachineInstr(const MachineInstr *MI) {
+  unsigned Hash = MI->getOpcode();
+  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+    const MachineOperand &Op = MI->getOperand(i);
+
+    // Merge in bits from the operand if easy.
+    unsigned OperandHash = 0;
+    switch (Op.getType()) {
+    case MachineOperand::MO_Register:
+      OperandHash = Op.getReg();
+      break;
+    case MachineOperand::MO_Immediate:
+      OperandHash = Op.getImm();
+      break;
+    case MachineOperand::MO_MachineBasicBlock:
+      OperandHash = Op.getMBB()->getNumber();
+      break;
+    case MachineOperand::MO_FrameIndex:
+    case MachineOperand::MO_ConstantPoolIndex:
+    case MachineOperand::MO_JumpTableIndex:
+      OperandHash = Op.getIndex();
+      break;
+    case MachineOperand::MO_GlobalAddress:
+    case MachineOperand::MO_ExternalSymbol:
+      // Global address / external symbol are too hard, don't bother, but do
+      // pull in the offset.
+      OperandHash = Op.getOffset();
+      break;
+    default:
+      break;
+    }
+
+    Hash += ((OperandHash << 3) | Op.getType()) << (i & 31);
+  }
+  return Hash;
+}
+
 /// HashEndOfMBB - Hash the last instruction in the MBB.
 static unsigned HashEndOfMBB(const MachineBasicBlock *MBB) {
-  auto LastInst = MBB->getLastNonDebugInstr();
-  if (LastInst == MBB->end())
-    return 0;
-  // Hash the instruction and all operands. MachineInstrExpressionTrait ignores
-  // vreg defs when computing the hash but we're post-regalloc here.
-  return MachineInstrExpressionTrait::getHashValue(LastInst);
+  MachineBasicBlock::const_iterator I = MBB->end();
+  if (I == MBB->begin())
+    return 0; // Empty MBB.
+
+  --I;
+  // Skip debug info so it will not affect codegen.
+  while (I->isDebugValue()) {
+    if (I == MBB->begin())
+      return 0; // MBB empty except for debug info.
+    --I;
+  }
+
+  return HashMachineInstr(I);
 }
 
 /// ComputeCommonTailLength - Given two machine basic blocks, compute the number