Fix and/or/xor (cast A), (cast B) --> cast (and/or/xor A, B)

The cast patch introduced the possibility that the wrong cast opcode
could be used and that this transform could trigger on different kinds
of cast operations. This patch rectifies that.

llvm-svn: 32538

1 files changed, 40 insertions, 41 deletions

diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
index 229fb8669d2..232e504971c 100644
--- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -3270,22 +3270,21 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
   }
 
   // fold (and (cast A), (cast B)) -> (cast (and A, B))
-  if (CastInst *Op1C = dyn_cast<CastInst>(Op1)) {
-    if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
-      const Type *SrcTy = Op0C->getOperand(0)->getType();
-      if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntegral() &&
-          // Only do this if the casts both really cause code to be generated.
-          ValueRequiresCast(Op0C->getOperand(0), I.getType(), TD) &&
-          ValueRequiresCast(Op1C->getOperand(0), I.getType(), TD)) {
-        Instruction *NewOp = BinaryOperator::createAnd(Op0C->getOperand(0),
-                                                       Op1C->getOperand(0),
-                                                       I.getName());
-        InsertNewInstBefore(NewOp, I);
-        return CastInst::createIntegerCast(NewOp, I.getType(), 
-                                           SrcTy->isSigned());
+  if (CastInst *Op0C = dyn_cast<CastInst>(Op0))
+    if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
+      if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind ?
+        const Type *SrcTy = Op0C->getOperand(0)->getType();
+        if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntegral() &&
+            // Only do this if the casts both really cause code to be generated.
+            ValueRequiresCast(Op0C->getOperand(0), I.getType(), TD) &&
+            ValueRequiresCast(Op1C->getOperand(0), I.getType(), TD)) {
+          Instruction *NewOp = BinaryOperator::createAnd(Op0C->getOperand(0),
+                                                         Op1C->getOperand(0),
+                                                         I.getName());
+          InsertNewInstBefore(NewOp, I);
+          return CastInst::create(Op0C->getOpcode(), NewOp, I.getType());
+        }
       }
-    }
-  }
     
   // (X >> Z) & (Y >> Z)  -> (X&Y) >> Z  for all shifts.
   if (ShiftInst *SI1 = dyn_cast<ShiftInst>(Op1)) {
@@ -3675,21 +3674,21 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
   }
     
   // fold (or (cast A), (cast B)) -> (cast (or A, B))
-  if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
-    const Type *SrcTy = Op0C->getOperand(0)->getType();
+  if (CastInst *Op0C = dyn_cast<CastInst>(Op0))
     if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
-      if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntegral() &&
-          // Only do this if the casts both really cause code to be generated.
-          ValueRequiresCast(Op0C->getOperand(0), I.getType(), TD) &&
-          ValueRequiresCast(Op1C->getOperand(0), I.getType(), TD)) {
-        Instruction *NewOp = BinaryOperator::createOr(Op0C->getOperand(0),
-                                                      Op1C->getOperand(0),
-                                                      I.getName());
-        InsertNewInstBefore(NewOp, I);
-        return CastInst::createIntegerCast(NewOp, I.getType(),
-                                           SrcTy->isSigned());
+      if (Op0C->getOpcode() == Op1C->getOpcode()) {// same cast kind ?
+        const Type *SrcTy = Op0C->getOperand(0)->getType();
+        if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntegral() &&
+            // Only do this if the casts both really cause code to be generated.
+            ValueRequiresCast(Op0C->getOperand(0), I.getType(), TD) &&
+            ValueRequiresCast(Op1C->getOperand(0), I.getType(), TD)) {
+          Instruction *NewOp = BinaryOperator::createOr(Op0C->getOperand(0),
+                                                        Op1C->getOperand(0),
+                                                        I.getName());
+          InsertNewInstBefore(NewOp, I);
+          return CastInst::create(Op0C->getOpcode(), NewOp, I.getType());
+        }
       }
-  }
       
 
   return Changed ? &I : 0;
@@ -3857,21 +3856,21 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
       return R;
 
   // fold (xor (cast A), (cast B)) -> (cast (xor A, B))
-  if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
-    const Type *SrcTy = Op0C->getOperand(0)->getType();
+  if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) 
     if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
-      if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntegral() &&
-          // Only do this if the casts both really cause code to be generated.
-          ValueRequiresCast(Op0C->getOperand(0), I.getType(), TD) &&
-          ValueRequiresCast(Op1C->getOperand(0), I.getType(), TD)) {
-        Instruction *NewOp = BinaryOperator::createXor(Op0C->getOperand(0),
-                                                       Op1C->getOperand(0),
-                                                       I.getName());
-        InsertNewInstBefore(NewOp, I);
-        return CastInst::createIntegerCast(NewOp, I.getType(), 
-                                           SrcTy->isSigned());
+      if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind?
+        const Type *SrcTy = Op0C->getOperand(0)->getType();
+        if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntegral() &&
+            // Only do this if the casts both really cause code to be generated.
+            ValueRequiresCast(Op0C->getOperand(0), I.getType(), TD) &&
+            ValueRequiresCast(Op1C->getOperand(0), I.getType(), TD)) {
+          Instruction *NewOp = BinaryOperator::createXor(Op0C->getOperand(0),
+                                                         Op1C->getOperand(0),
+                                                         I.getName());
+          InsertNewInstBefore(NewOp, I);
+          return CastInst::create(Op0C->getOpcode(), NewOp, I.getType());
+        }
       }
-  }
 
   // (X >> Z) ^ (Y >> Z)  -> (X^Y) >> Z  for all shifts.
   if (ShiftInst *SI1 = dyn_cast<ShiftInst>(Op1)) {