- Expose passinfo from BreakCriticalEdges pass so that it may be "Required"

[oota-llvm.git] / lib / Transforms / Scalar / InstructionCombining.cpp

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 785eb709aa4cb94b88433cd7e09eb7bc408b3d91..b60d1fa9720ff7f4044950bba12d82961f23c099 100644 (file)
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -490,10 +490,18 @@ Instruction *InstCombiner::visitShiftInst(Instruction &I) {
   // a signed value.
   //
   if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(Op1)) {
-    unsigned TypeBits = Op0->getType()->getPrimitiveSize()*8;
-    if (CUI->getValue() >= TypeBits &&
-        !(Op0->getType()->isSigned() && I.getOpcode() == Instruction::Shr))
-      return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
+    if (I.getOpcode() == Instruction::Shr) {
+      unsigned TypeBits = Op0->getType()->getPrimitiveSize()*8;
+      if (CUI->getValue() >= TypeBits && !(Op0->getType()->isSigned()))
+        return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
+    }
+
+    // Check to see if we are shifting left by 1.  If so, turn it into an add
+    // instruction.
+    if (I.getOpcode() == Instruction::Shl && CUI->equalsInt(1))
+      // Convert 'shl int %X, 2' to 'add int %X, %X'
+      return BinaryOperator::create(Instruction::Add, Op0, Op0, I.getName());
+
   }
   return 0;
 }
@@ -528,6 +536,12 @@ static inline bool isEliminableCastOfCast(const CastInst &CI,
     if (SrcSize >= MidSize && MidSize >= DstSize)
       return true;
 
+    // Cases where the source and destination type are the same, but the middle
+    // type is bigger are noops.
+    //
+    if (SrcSize == DstSize && MidSize > SrcSize)
+      return true;
+
     // If we are monotonically growing, things are more complex.
     //
     if (SrcSize <= MidSize && MidSize <= DstSize) {
@@ -641,7 +655,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
   // Is it 'getelementptr %P, uint 0'  or 'getelementptr %P'
   // If so, eliminate the noop.
   if ((GEP.getNumOperands() == 2 &&
-       GEP.getOperand(1) == Constant::getNullValue(Type::UIntTy)) ||
+       GEP.getOperand(1) == Constant::getNullValue(Type::LongTy)) ||
       GEP.getNumOperands() == 1)
     return ReplaceInstUsesWith(GEP, GEP.getOperand(0));
 
@@ -661,7 +675,8 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
                    *cast<Constant>(GEP.getOperand(1));
       assert(Indices[0] != 0 && "Constant folding of uint's failed!?");
 
-    } else if (*GEP.idx_begin() == ConstantUInt::get(Type::UIntTy, 0)) { 
+    } else if (*GEP.idx_begin() == ConstantUInt::getNullValue(Type::LongTy) &&
+               Src->getNumOperands() != 1) { 
       // Otherwise we can do the fold if the first index of the GEP is a zero
       Indices.insert(Indices.end(), Src->idx_begin(), Src->idx_end());
       Indices.insert(Indices.end(), GEP.idx_begin()+1, GEP.idx_end());