- Change MachineInstr::isIdenticalTo to take a new option that determines whether it should skip checking defs or at least virtual register defs. This subsumes part of the TargetInstrInfo::isIdentical functionality.

- Eliminate TargetInstrInfo::isIdentical and replace it with produceSameValue. In the default case, produceSameValue just checks whether two machine instructions are identical (except for virtual register defs). But targets may override it to check for unusual cases (e.g. ARM pic loads from constant pools).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97628 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/MachineInstr.cpp

@@ -18,6 +18,7 @@
 #include "llvm/Type.h"
 #include "llvm/Value.h"
 #include "llvm/Assembly/Writer.h"
+#include "llvm/CodeGen/MachineConstantPool.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineMemOperand.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
@@ -701,6 +702,28 @@ void MachineInstr::addMemOperand(MachineFunction &MF,
   MemRefsEnd = NewMemRefsEnd;
 }
 
+bool MachineInstr::isIdenticalTo(const MachineInstr *Other,
+                                 MICheckType Check) const {
+    if (Other->getOpcode() != getOpcode() ||
+        Other->getNumOperands() != getNumOperands())
+      return false;
+    for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
+      const MachineOperand &MO = getOperand(i);
+      const MachineOperand &OMO = Other->getOperand(i);
+      if (Check != CheckDefs && MO.isReg() && MO.isDef()) {
+        if (Check == IgnoreDefs)
+          continue;
+        // Check == IgnoreVRegDefs
+        if (TargetRegisterInfo::isPhysicalRegister(MO.getReg()) ||
+            TargetRegisterInfo::isPhysicalRegister(OMO.getReg()))
+          if (MO.getReg() != OMO.getReg())
+            return false;
+      } else if (!MO.isIdenticalTo(OMO))
+        return false;
+    }
+    return true;
+}
+
 /// removeFromParent - This method unlinks 'this' from the containing basic
 /// block, and returns it, but does not delete it.
 MachineInstr *MachineInstr::removeFromParent() {