Refactor operation equivalence checking in BBVectorize by extending Instruction::isSameOperationAs.

Maintaining this kind of checking in different places is dangerous, extending
Instruction::isSameOperationAs consolidates this logic into one place. Here
I've added an optional flags parameter and two flags that are important for
vectorization: CompareIgnoringAlignment and CompareUsingScalarTypes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159329 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Instruction.h

@@ -281,6 +281,16 @@ public:
   /// ignores the SubclassOptionalData flags, which specify conditions
   /// under which the instruction's result is undefined.
   bool isIdenticalToWhenDefined(const Instruction *I) const;
+
+  /// When checking for operation equivalence (using isSameOperationAs) it is
+  /// sometimes useful to ignore certain attributes.
+  enum OperationEquivalenceFlags {
+    /// Check for equivalence ignoring load/store alignment.
+    CompareIgnoringAlignment = 1<<0,
+    /// Check for equivalence treating a type and a vector of that type
+    /// as equivalent.
+    CompareUsingScalarTypes = 1<<1
+  };
   
   /// This function determines if the specified instruction executes the same
   /// operation as the current one. This means that the opcodes, type, operand
@@ -290,7 +300,7 @@ public:
   /// @returns true if the specified instruction is the same operation as
   /// the current one.
   /// @brief Determine if one instruction is the same operation as another.
-  bool isSameOperationAs(const Instruction *I) const;
+  bool isSameOperationAs(const Instruction *I, unsigned flags = 0) const;
   
   /// isUsedOutsideOfBlock - Return true if there are any uses of this
   /// instruction in blocks other than the specified block.  Note that PHI nodes

lib/Transforms/Vectorize/BBVectorize.cpp

@@ -660,30 +660,9 @@ namespace {
 
     // Loads and stores can be merged if they have different alignments,
     // but are otherwise the same.
-    LoadInst *LI, *LJ;
+    if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment))
-    StoreInst *SI, *SJ;
-    if ((LI = dyn_cast<LoadInst>(I)) && (LJ = dyn_cast<LoadInst>(J))) {
-      if (I->getType() != J->getType())
-        return false;
-
-      if (LI->getPointerOperand()->getType() !=
-            LJ->getPointerOperand()->getType() ||
-          LI->isVolatile() != LJ->isVolatile() ||
-          LI->getOrdering() != LJ->getOrdering() ||
-          LI->getSynchScope() != LJ->getSynchScope())
-        return false;
-    } else if ((SI = dyn_cast<StoreInst>(I)) && (SJ = dyn_cast<StoreInst>(J))) {
-      if (SI->getValueOperand()->getType() !=
-            SJ->getValueOperand()->getType() ||
-          SI->getPointerOperand()->getType() !=
-            SJ->getPointerOperand()->getType() ||
-          SI->isVolatile() != SJ->isVolatile() ||
-          SI->getOrdering() != SJ->getOrdering() ||
-          SI->getSynchScope() != SJ->getSynchScope())
-        return false;
-    } else if (!J->isSameOperationAs(I)) {
       return false;
-    }
+
     // FIXME: handle addsub-type operations!
 
     if (IsSimpleLoadStore) {

lib/VMCore/Instruction.cpp

@@ -240,27 +240,38 @@ bool Instruction::isIdenticalToWhenDefined(const Instruction *I) const {
 // isSameOperationAs
 // This should be kept in sync with isEquivalentOperation in
 // lib/Transforms/IPO/MergeFunctions.cpp.
-bool Instruction::isSameOperationAs(const Instruction *I) const {
+bool Instruction::isSameOperationAs(const Instruction *I,
+                                    unsigned flags) const {
+  bool IgnoreAlignment = flags & CompareIgnoringAlignment;
+  bool UseScalarTypes  = flags & CompareUsingScalarTypes;
+
   if (getOpcode() != I->getOpcode() ||
       getNumOperands() != I->getNumOperands() ||
-      getType() != I->getType())
+      (UseScalarTypes ?
+       getType()->getScalarType() != I->getType()->getScalarType() :
+       getType() != I->getType()))
     return false;
 
   // We have two instructions of identical opcode and #operands.  Check to see
   // if all operands are the same type
   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
-    if (getOperand(i)->getType() != I->getOperand(i)->getType())
+    if (UseScalarTypes ?
+        getOperand(i)->getType()->getScalarType() !=
+          I->getOperand(i)->getType()->getScalarType() :
+        getOperand(i)->getType() != I->getOperand(i)->getType())
       return false;
 
   // Check special state that is a part of some instructions.
   if (const LoadInst *LI = dyn_cast<LoadInst>(this))
     return LI->isVolatile() == cast<LoadInst>(I)->isVolatile() &&
-           LI->getAlignment() == cast<LoadInst>(I)->getAlignment() &&
+           (LI->getAlignment() == cast<LoadInst>(I)->getAlignment() ||
+            IgnoreAlignment) &&
            LI->getOrdering() == cast<LoadInst>(I)->getOrdering() &&
            LI->getSynchScope() == cast<LoadInst>(I)->getSynchScope();
   if (const StoreInst *SI = dyn_cast<StoreInst>(this))
     return SI->isVolatile() == cast<StoreInst>(I)->isVolatile() &&
-           SI->getAlignment() == cast<StoreInst>(I)->getAlignment() &&
+           (SI->getAlignment() == cast<StoreInst>(I)->getAlignment() ||
+            IgnoreAlignment) &&
            SI->getOrdering() == cast<StoreInst>(I)->getOrdering() &&
            SI->getSynchScope() == cast<StoreInst>(I)->getSynchScope();
   if (const CmpInst *CI = dyn_cast<CmpInst>(this))