llvm/clang/test/CodeGenObjC/optimize-ivar-offset-load.m

// RUN: %clang_cc1 -triple x86_64-apple-darwin10  -O0 -emit-llvm %s -o -  | FileCheck %s

@interface MyNSObject 
@end

@interface SampleClass : MyNSObject {
    @public
    int _value;
}
+ (SampleClass*) new;
@end

@interface AppDelegate  : MyNSObject
@end

extern void foo(int);

@implementation AppDelegate
- (void)application
{
    // Create set of objects in loop
    for(int i = 0; i < 2; i++) {
        SampleClass *sample = [SampleClass new];
        foo (sample->_value);
    }
}
@end
// CHECK: [[IVAR:%.*]]  = load i64, ptr @"OBJC_IVAR_$_SampleClass._value", align 8
// CHECK: [[ADDPTR:%.*]] = getelementptr inbounds i8, ptr [[CALL:%.*]], i64 [[IVAR]]
// CHECK: [[FIVE:%.*]] = load i32, ptr [[ADDPTR]], align 4
// CHECK:   call void @foo(i32 noundef [[FIVE]])

@implementation SampleClass
+ (SampleClass*) new { return 0; }
- (void) SampleClassApplication
{
    // Create set of objects in loop
    for(int i = 0; i < 2; i++) {
        SampleClass *sample = [SampleClass new];
        foo (sample->_value);
    }
}
@end
// CHECK: [[ZERO:%.*]] = load ptr, ptr @OBJC_SELECTOR_REFERENCES_, align 8, !invariant.load
// CHECK: [[IVAR:%.*]] = load i64, ptr @"OBJC_IVAR_$_SampleClass._value", align 8, !invariant.load

@interface Sample : SampleClass @end

@implementation Sample
- (void) SampleApplication
{
    // Create set of objects in loop
    for(int i = 0; i < 2; i++) {
        SampleClass *sample = [SampleClass new];
        foo (sample->_value);
    }
}
@end
// CHECK: [[ZERO:%.*]] = load ptr, ptr @OBJC_SELECTOR_REFERENCES_, align 8, !invariant.load 
// CHECK: [[IVAR:%.*]] = load i64, ptr @"OBJC_IVAR_$_SampleClass._value", align 8, !invariant.load