[clang] Remove no-op ptr-to-ptr bitcasts (NFC)

Opaque ptr cleanup effort (NFC)

Author: JOE1994

clang/lib/CodeGen/CGBlocks.cpp

@@ -164,8 +164,7 @@ static llvm::Constant *buildBlockDescriptor(CodeGenModule &CGM,
       CGM.getLangOpts().getGC() == LangOptions::NonGC) {
     descName = getBlockDescriptorName(blockInfo, CGM);
     if (llvm::GlobalValue *desc = CGM.getModule().getNamedValue(descName))
-      return llvm::ConstantExpr::getBitCast(desc,
-                                            CGM.getBlockDescriptorType());
+      return desc;
   }
 
   // If there isn't an equivalent block descriptor global variable, create a new
@@ -242,7 +241,7 @@ static llvm::Constant *buildBlockDescriptor(CodeGenModule &CGM,
     global->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
   }
 
-  return llvm::ConstantExpr::getBitCast(global, CGM.getBlockDescriptorType());
+  return global;
 }
 
 /*

clang/lib/CodeGen/CGDeclCXX.cpp

@@ -126,7 +126,7 @@ static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
           CGM.getLLVMContext(), CGM.getContext().getTargetAddressSpace(DestAS));
       auto SrcAS = D.getType().getQualifiers().getAddressSpace();
       if (DestAS == SrcAS)
-        Argument = llvm::ConstantExpr::getBitCast(Addr.getPointer(), DestTy);
+        Argument = Addr.getPointer();
       else
         // FIXME: On addr space mismatch we are passing NULL. The generation
         // of the global destructor function should be adjusted accordingly.
@@ -167,8 +167,7 @@ void CodeGenFunction::EmitInvariantStart(llvm::Constant *Addr, CharUnits Size) {
 
   // Emit a call with the size in bytes of the object.
   uint64_t Width = Size.getQuantity();
-  llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(Int64Ty, Width),
-                           llvm::ConstantExpr::getBitCast(Addr, Int8PtrTy)};
+  llvm::Value *Args[2] = {llvm::ConstantInt::getSigned(Int64Ty, Width), Addr};
   Builder.CreateCall(InvariantStart, Args);
 }
 

clang/lib/CodeGen/CGExprConstant.cpp

@@ -1630,13 +1630,8 @@ namespace {
         IndexValues[i] = llvm::ConstantInt::get(CGM.Int32Ty, Indices[i]);
       }
 
-      // Form a GEP and then bitcast to the placeholder type so that the
-      // replacement will succeed.
-      llvm::Constant *location =
-        llvm::ConstantExpr::getInBoundsGetElementPtr(BaseValueTy,
-                                                     Base, IndexValues);
-      location = llvm::ConstantExpr::getBitCast(location,
-                                                placeholder->getType());
+      llvm::Constant *location = llvm::ConstantExpr::getInBoundsGetElementPtr(
+          BaseValueTy, Base, IndexValues);
 
       Locations.insert({placeholder, location});
     }
@@ -2037,8 +2032,6 @@ ConstantLValue
 ConstantLValueEmitter::VisitAddrLabelExpr(const AddrLabelExpr *E) {
   assert(Emitter.CGF && "Invalid address of label expression outside function");
   llvm::Constant *Ptr = Emitter.CGF->GetAddrOfLabel(E->getLabel());
-  Ptr = llvm::ConstantExpr::getBitCast(Ptr,
-                                   CGM.getTypes().ConvertType(E->getType()));
   return Ptr;
 }