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

Opaque ptr cleanup effort (NFC).

Author: JOE1994

clang/lib/CodeGen/CGObjC.cpp

@@ -827,11 +827,8 @@ static void emitStructGetterCall(CodeGenFunction &CGF, ObjCIvarDecl *ivar,
   //                  sizeof (Type of Ivar), isAtomic, false);
   CallArgList args;
 
-  llvm::Value *dest =
-      CGF.Builder.CreateBitCast(CGF.ReturnValue.getPointer(), CGF.VoidPtrTy);
+  llvm::Value *dest = CGF.ReturnValue.getPointer();
   args.add(RValue::get(dest), Context.VoidPtrTy);
-
-  src = CGF.Builder.CreateBitCast(src, CGF.VoidPtrTy);
   args.add(RValue::get(src), Context.VoidPtrTy);
 
   CharUnits size = CGF.getContext().getTypeSizeInChars(ivar->getType());
@@ -1098,7 +1095,6 @@ static void emitCPPObjectAtomicGetterCall(CodeGenFunction &CGF,
   llvm::Value *ivarAddr =
       CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(), ivar, 0)
           .getPointer(CGF);
-  ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
   args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
 
   // Third argument is the helper function.
@@ -1340,7 +1336,6 @@ static void emitStructSetterCall(CodeGenFunction &CGF, ObjCMethodDecl *OMD,
                      argVar->getType().getNonReferenceType(), VK_LValue,
                      SourceLocation());
   llvm::Value *argAddr = CGF.EmitLValue(&argRef).getPointer(CGF);
-  argAddr = CGF.Builder.CreateBitCast(argAddr, CGF.Int8PtrTy);
   args.add(RValue::get(argAddr), CGF.getContext().VoidPtrTy);
 
   // The third argument is the sizeof the type.
@@ -1377,7 +1372,6 @@ static void emitCPPObjectAtomicSetterCall(CodeGenFunction &CGF,
   llvm::Value *ivarAddr =
       CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(), ivar, 0)
           .getPointer(CGF);
-  ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
   args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
 
   // The second argument is the address of the parameter variable.
@@ -1386,7 +1380,6 @@ static void emitCPPObjectAtomicSetterCall(CodeGenFunction &CGF,
                      argVar->getType().getNonReferenceType(), VK_LValue,
                      SourceLocation());
   llvm::Value *argAddr = CGF.EmitLValue(&argRef).getPointer(CGF);
-  argAddr = CGF.Builder.CreateBitCast(argAddr, CGF.Int8PtrTy);
   args.add(RValue::get(argAddr), CGF.getContext().VoidPtrTy);
 
   // Third argument is the helper function.
@@ -3685,7 +3678,6 @@ void CodeGenFunction::EmitExtendGCLifetime(llvm::Value *object) {
                                                    /* constraints */ "r",
                                                    /* side effects */ true);
 
-  object = Builder.CreateBitCast(object, VoidPtrTy);
   EmitNounwindRuntimeCall(extender, object);
 }
 

clang/lib/CodeGen/MicrosoftCXXABI.cpp

@@ -2266,7 +2266,6 @@ MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, Address Ret,
   if (RA.isEmpty())
     return Ret.getPointer();
 
-  auto OrigTy = Ret.getType();
   Ret = Ret.withElementType(CGF.Int8Ty);
 
   llvm::Value *V = Ret.getPointer();
@@ -2283,8 +2282,7 @@ MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, Address Ret,
   if (RA.NonVirtual)
     V = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, V, RA.NonVirtual);
 
-  // Cast back to the original type.
-  return CGF.Builder.CreateBitCast(V, OrigTy);
+  return V;
 }
 
 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,