InstCombine: ((A & ~B) ^ (~A & B)) to A ^ B

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

diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index d3648e2d05053a8c891242051bc3feb7ff77ad9b..e079eee7d2c4d2c446cfe7cc0f0797ab6e98174d 100644 (file)
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1667,6 +1667,18 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
   if (!DL)
     return nullptr;
 
+  // addrspacecast between types is canonicalized as a bitcast, then an
+  // addrspacecast. To take advantage of the below bitcast + struct GEP, look
+  // through the addrspacecast.
+  if (AddrSpaceCastInst *ASC = dyn_cast<AddrSpaceCastInst>(PtrOp)) {
+    //   X = bitcast A addrspace(1)* to B addrspace(1)*
+    //   Y = addrspacecast A addrspace(1)* to B addrspace(2)*
+    //   Z = gep Y, <...constant indices...>
+    // Into an addrspacecasted GEP of the struct.
+    if (BitCastInst *BC = dyn_cast<BitCastInst>(ASC->getOperand(0)))
+      PtrOp = BC;
+  }
+
   /// See if we can simplify:
   ///   X = bitcast A* to B*
   ///   Y = gep X, <...constant indices...>
@@ -1675,11 +1687,10 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
   if (BitCastInst *BCI = dyn_cast<BitCastInst>(PtrOp)) {
     Value *Operand = BCI->getOperand(0);
     PointerType *OpType = cast<PointerType>(Operand->getType());
-    unsigned OffsetBits = DL->getPointerTypeSizeInBits(OpType);
+    unsigned OffsetBits = DL->getPointerTypeSizeInBits(GEP.getType());
     APInt Offset(OffsetBits, 0);
     if (!isa<BitCastInst>(Operand) &&
-        GEP.accumulateConstantOffset(*DL, Offset) &&
-        StrippedPtrTy->getAddressSpace() == GEP.getPointerAddressSpace()) {
+        GEP.accumulateConstantOffset(*DL, Offset)) {
 
       // If this GEP instruction doesn't move the pointer, just replace the GEP
       // with a bitcast of the real input to the dest type.
@@ -1697,6 +1708,9 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
             return &GEP;
           }
         }
+
+        if (Operand->getType()->getPointerAddressSpace() != GEP.getAddressSpace())
+          return new AddrSpaceCastInst(Operand, GEP.getType());
         return new BitCastInst(Operand, GEP.getType());
       }
 
@@ -1712,6 +1726,9 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
         if (NGEP->getType() == GEP.getType())
           return ReplaceInstUsesWith(GEP, NGEP);
         NGEP->takeName(&GEP);
+
+        if (NGEP->getType()->getPointerAddressSpace() != GEP.getAddressSpace())
+          return new AddrSpaceCastInst(NGEP, GEP.getType());
         return new BitCastInst(NGEP, GEP.getType());
       }
     }