diff --git a/doc/langref.md b/doc/langref.md
index c202925ae3..6d6b9b63ce 100644
--- a/doc/langref.md
+++ b/doc/langref.md
@@ -630,3 +630,7 @@ Converts an integer to a pointer. To convert the other way, use `usize(ptr)`.
 ### @enumTagName(value: var) -> []const u8
 
 Converts an enum tag name to a slice of bytes. Example:
+
+### @fieldParentPtr(comptime ParentType: type, comptime field_name: []const u8, field_ptr: &T) -> &ParentType
+
+Given a pointer to a field, returns the base pointer of a struct.
diff --git a/src/all_types.hpp b/src/all_types.hpp
index 0c6af587da..80f17afdd4 100644
--- a/src/all_types.hpp
+++ b/src/all_types.hpp
@@ -1189,6 +1189,7 @@ enum BuiltinFnId {
     BuiltinFnIdPtrCast,
     BuiltinFnIdIntToPtr,
     BuiltinFnIdEnumTagName,
+    BuiltinFnIdFieldParentPtr,
 };
 
 struct BuiltinFnEntry {
@@ -1736,6 +1737,7 @@ enum IrInstructionId {
     IrInstructionIdPanic,
     IrInstructionIdEnumTagName,
     IrInstructionIdSetFnRefInline,
+    IrInstructionIdFieldParentPtr,
 };
 
 struct IrInstruction {
@@ -2488,6 +2490,15 @@ struct IrInstructionSetFnRefInline {
     IrInstruction *fn_ref;
 };
 
+struct IrInstructionFieldParentPtr {
+    IrInstruction base;
+
+    IrInstruction *type_value;
+    IrInstruction *field_name;
+    IrInstruction *field_ptr;
+    TypeStructField *field;
+};
+
 static const size_t slice_ptr_index = 0;
 static const size_t slice_len_index = 1;
 
diff --git a/src/codegen.cpp b/src/codegen.cpp
index 7222cd3fc8..d5f1cfe4f6 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -2261,6 +2261,34 @@ static LLVMValueRef ir_render_enum_tag_name(CodeGen *g, IrExecutable *executable
     return LLVMBuildInBoundsGEP(g->builder, enum_tag_type->data.enum_tag.name_table, indices, 2, "");
 }
 
+static LLVMValueRef ir_render_field_parent_ptr(CodeGen *g, IrExecutable *executable,
+        IrInstructionFieldParentPtr *instruction)
+{
+    TypeTableEntry *container_ptr_type = instruction->base.value.type;
+    assert(container_ptr_type->id == TypeTableEntryIdPointer);
+
+    TypeTableEntry *container_type = container_ptr_type->data.pointer.child_type;
+
+    size_t byte_offset = LLVMOffsetOfElement(g->target_data_ref,
+            container_type->type_ref, instruction->field->gen_index);
+
+    LLVMValueRef field_ptr_val = ir_llvm_value(g, instruction->field_ptr);
+
+    if (byte_offset == 0) {
+        return LLVMBuildBitCast(g->builder, field_ptr_val, container_ptr_type->type_ref, "");
+    } else {
+        TypeTableEntry *usize = g->builtin_types.entry_usize;
+
+        LLVMValueRef field_ptr_int = LLVMBuildPtrToInt(g->builder, field_ptr_val,
+                usize->type_ref, "");
+
+        LLVMValueRef base_ptr_int = LLVMBuildNUWSub(g->builder, field_ptr_int,
+                LLVMConstInt(usize->type_ref, byte_offset, false), "");
+
+        return LLVMBuildIntToPtr(g->builder, base_ptr_int, container_ptr_type->type_ref, "");
+    }
+}
+
 
 static LLVMAtomicOrdering to_LLVMAtomicOrdering(AtomicOrder atomic_order) {
     switch (atomic_order) {
@@ -2963,6 +2991,8 @@ static LLVMValueRef ir_render_instruction(CodeGen *g, IrExecutable *executable,
             return ir_render_panic(g, executable, (IrInstructionPanic *)instruction);
         case IrInstructionIdEnumTagName:
             return ir_render_enum_tag_name(g, executable, (IrInstructionEnumTagName *)instruction);
+        case IrInstructionIdFieldParentPtr:
+            return ir_render_field_parent_ptr(g, executable, (IrInstructionFieldParentPtr *)instruction);
     }
     zig_unreachable();
 }
@@ -4509,6 +4539,7 @@ static void define_builtin_fns(CodeGen *g) {
     create_builtin_fn(g, BuiltinFnIdPtrCast, "ptrcast", 2);
     create_builtin_fn(g, BuiltinFnIdIntToPtr, "intToPtr", 2);
     create_builtin_fn(g, BuiltinFnIdEnumTagName, "enumTagName", 1);
+    create_builtin_fn(g, BuiltinFnIdFieldParentPtr, "fieldParentPtr", 3);
 }
 
 static void add_compile_var(CodeGen *g, const char *name, ConstExprValue *value) {
diff --git a/src/ir.cpp b/src/ir.cpp
index 9b6cb8ab36..8bdf90057c 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -549,6 +549,10 @@ static constexpr IrInstructionId ir_instruction_id(IrInstructionSetFnRefInline *
     return IrInstructionIdSetFnRefInline;
 }
 
+static constexpr IrInstructionId ir_instruction_id(IrInstructionFieldParentPtr *) {
+    return IrInstructionIdFieldParentPtr;
+}
+
 template<typename T>
 static T *ir_create_instruction(IrBuilder *irb, Scope *scope, AstNode *source_node) {
     T *special_instruction = allocate<T>(1);
@@ -2162,6 +2166,23 @@ static IrInstruction *ir_build_set_fn_ref_inline(IrBuilder *irb, Scope *scope, A
     return &instruction->base;
 }
 
+static IrInstruction *ir_build_field_parent_ptr(IrBuilder *irb, Scope *scope, AstNode *source_node,
+        IrInstruction *type_value, IrInstruction *field_name, IrInstruction *field_ptr, TypeStructField *field)
+{
+    IrInstructionFieldParentPtr *instruction = ir_build_instruction<IrInstructionFieldParentPtr>(
+            irb, scope, source_node);
+    instruction->type_value = type_value;
+    instruction->field_name = field_name;
+    instruction->field_ptr = field_ptr;
+    instruction->field = field;
+
+    ir_ref_instruction(type_value, irb->current_basic_block);
+    ir_ref_instruction(field_name, irb->current_basic_block);
+    ir_ref_instruction(field_ptr, irb->current_basic_block);
+
+    return &instruction->base;
+}
+
 static IrInstruction *ir_instruction_br_get_dep(IrInstructionBr *instruction, size_t index) {
     return nullptr;
 }
@@ -2833,6 +2854,15 @@ static IrInstruction *ir_instruction_setfnrefinline_get_dep(IrInstructionSetFnRe
     }
 }
 
+static IrInstruction *ir_instruction_fieldparentptr_get_dep(IrInstructionFieldParentPtr *instruction, size_t index) {
+    switch (index) {
+        case 0: return instruction->type_value;
+        case 1: return instruction->field_name;
+        case 2: return instruction->field_ptr;
+        default: return nullptr;
+    }
+}
+
 
 static IrInstruction *ir_instruction_get_dep(IrInstruction *instruction, size_t index) {
     switch (instruction->id) {
@@ -3026,6 +3056,8 @@ static IrInstruction *ir_instruction_get_dep(IrInstruction *instruction, size_t
             return ir_instruction_enumtagname_get_dep((IrInstructionEnumTagName *) instruction, index);
         case IrInstructionIdSetFnRefInline:
             return ir_instruction_setfnrefinline_get_dep((IrInstructionSetFnRefInline *) instruction, index);
+        case IrInstructionIdFieldParentPtr:
+            return ir_instruction_fieldparentptr_get_dep((IrInstructionFieldParentPtr *) instruction, index);
     }
     zig_unreachable();
 }
@@ -4333,6 +4365,25 @@ static IrInstruction *ir_gen_builtin_fn_call(IrBuilder *irb, Scope *scope, AstNo
                 IrInstruction *actual_tag = ir_build_enum_tag(irb, scope, node, arg0_value);
                 return ir_build_enum_tag_name(irb, scope, node, actual_tag);
             }
+        case BuiltinFnIdFieldParentPtr:
+            {
+                AstNode *arg0_node = node->data.fn_call_expr.params.at(0);
+                IrInstruction *arg0_value = ir_gen_node(irb, arg0_node, scope);
+                if (arg0_value == irb->codegen->invalid_instruction)
+                    return arg0_value;
+
+                AstNode *arg1_node = node->data.fn_call_expr.params.at(1);
+                IrInstruction *arg1_value = ir_gen_node(irb, arg1_node, scope);
+                if (arg1_value == irb->codegen->invalid_instruction)
+                    return arg1_value;
+
+                AstNode *arg2_node = node->data.fn_call_expr.params.at(2);
+                IrInstruction *arg2_value = ir_gen_node(irb, arg2_node, scope);
+                if (arg2_value == irb->codegen->invalid_instruction)
+                    return arg2_value;
+
+                return ir_build_field_parent_ptr(irb, scope, node, arg0_value, arg1_value, arg2_value, nullptr);
+            }
     }
     zig_unreachable();
 }
@@ -11263,6 +11314,89 @@ static TypeTableEntry *ir_analyze_instruction_set_fn_ref_inline(IrAnalyze *ira,
     }
 }
 
+static TypeTableEntry *ir_analyze_instruction_field_parent_ptr(IrAnalyze *ira,
+        IrInstructionFieldParentPtr *instruction)
+{
+    IrInstruction *type_value = instruction->type_value->other;
+    TypeTableEntry *container_type = ir_resolve_type(ira, type_value);
+    if (type_is_invalid(container_type))
+        return ira->codegen->builtin_types.entry_invalid;
+
+    IrInstruction *field_name_value = instruction->field_name->other;
+    Buf *field_name = ir_resolve_str(ira, field_name_value);
+    if (!field_name)
+        return ira->codegen->builtin_types.entry_invalid;
+
+    IrInstruction *field_ptr = instruction->field_ptr->other;
+    if (type_is_invalid(field_ptr->value.type))
+        return ira->codegen->builtin_types.entry_invalid;
+
+    if (container_type->id != TypeTableEntryIdStruct) {
+        ir_add_error(ira, type_value,
+                buf_sprintf("expected struct type, found '%s'", buf_ptr(&container_type->name)));
+        return ira->codegen->builtin_types.entry_invalid;
+    }
+
+    ensure_complete_type(ira->codegen, container_type);
+
+    TypeStructField *field = find_struct_type_field(container_type, field_name);
+    if (field == nullptr) {
+        ir_add_error(ira, field_name_value,
+                buf_sprintf("struct '%s' has no field '%s'",
+                    buf_ptr(&container_type->name), buf_ptr(field_name)));
+        return ira->codegen->builtin_types.entry_invalid;
+    }
+
+    if (field_ptr->value.type->id != TypeTableEntryIdPointer) {
+        ir_add_error(ira, field_ptr,
+                buf_sprintf("expected pointer, found '%s'", buf_ptr(&field_ptr->value.type->name)));
+        return ira->codegen->builtin_types.entry_invalid;
+    }
+
+    TypeTableEntry *field_ptr_type = get_pointer_to_type_extra(ira->codegen, field->type_entry,
+            field_ptr->value.type->data.pointer.is_const,
+            field_ptr->value.type->data.pointer.is_volatile, 0, 0);
+    IrInstruction *casted_field_ptr = ir_implicit_cast(ira, field_ptr, field_ptr_type);
+    if (type_is_invalid(casted_field_ptr->value.type))
+        return ira->codegen->builtin_types.entry_invalid;
+
+    TypeTableEntry *result_type = get_pointer_to_type_extra(ira->codegen, container_type,
+            casted_field_ptr->value.type->data.pointer.is_const,
+            casted_field_ptr->value.type->data.pointer.is_volatile, 0, 0);
+
+    if (instr_is_comptime(casted_field_ptr)) {
+        ConstExprValue *field_ptr_val = ir_resolve_const(ira, casted_field_ptr, UndefBad);
+        if (!field_ptr_val)
+            return ira->codegen->builtin_types.entry_invalid;
+
+        if (field_ptr_val->data.x_ptr.special != ConstPtrSpecialBaseStruct) {
+            ir_add_error(ira, field_ptr, buf_sprintf("pointer value not based on parent struct"));
+            return ira->codegen->builtin_types.entry_invalid;
+        }
+
+        size_t ptr_field_index = field_ptr_val->data.x_ptr.data.base_struct.field_index;
+        if (ptr_field_index != field->src_index) {
+            ir_add_error(ira, &instruction->base,
+                    buf_sprintf("field '%s' has index %zu but pointer value is index %zu of struct '%s'",
+                        buf_ptr(field->name), field->src_index,
+                        ptr_field_index, buf_ptr(&container_type->name)));
+            return ira->codegen->builtin_types.entry_invalid;
+        }
+
+        ConstExprValue *out_val = ir_build_const_from(ira, &instruction->base);
+        out_val->data.x_ptr.special = ConstPtrSpecialRef;
+        out_val->data.x_ptr.data.ref.pointee = field_ptr_val->data.x_ptr.data.base_struct.struct_val;
+        out_val->data.x_ptr.mut = field_ptr_val->data.x_ptr.mut;
+
+        return result_type;
+    }
+
+    IrInstruction *result = ir_build_field_parent_ptr(&ira->new_irb, instruction->base.scope,
+            instruction->base.source_node, type_value, field_name_value, casted_field_ptr, field);
+    ir_link_new_instruction(result, &instruction->base);
+    return result_type;
+}
+
 static TypeTableEntry *ir_analyze_instruction_type_name(IrAnalyze *ira, IrInstructionTypeName *instruction) {
     IrInstruction *type_value = instruction->type_value->other;
     TypeTableEntry *type_entry = ir_resolve_type(ira, type_value);
@@ -12781,6 +12915,8 @@ static TypeTableEntry *ir_analyze_instruction_nocast(IrAnalyze *ira, IrInstructi
             return ir_analyze_instruction_enum_tag_name(ira, (IrInstructionEnumTagName *)instruction);
         case IrInstructionIdSetFnRefInline:
             return ir_analyze_instruction_set_fn_ref_inline(ira, (IrInstructionSetFnRefInline *)instruction);
+        case IrInstructionIdFieldParentPtr:
+            return ir_analyze_instruction_field_parent_ptr(ira, (IrInstructionFieldParentPtr *)instruction);
         case IrInstructionIdMaybeWrap:
         case IrInstructionIdErrWrapCode:
         case IrInstructionIdErrWrapPayload:
@@ -12964,6 +13100,7 @@ bool ir_has_side_effects(IrInstruction *instruction) {
         case IrInstructionIdTypeName:
         case IrInstructionIdEnumTagName:
         case IrInstructionIdSetFnRefInline:
+        case IrInstructionIdFieldParentPtr:
             return false;
         case IrInstructionIdAsm:
             {
diff --git a/src/ir_print.cpp b/src/ir_print.cpp
index 7670dfa09e..569f038895 100644
--- a/src/ir_print.cpp
+++ b/src/ir_print.cpp
@@ -875,6 +875,16 @@ static void ir_print_set_fn_ref_inline(IrPrint *irp, IrInstructionSetFnRefInline
     ir_print_other_instruction(irp, instruction->fn_ref);
 }
 
+static void ir_print_field_parent_ptr(IrPrint *irp, IrInstructionFieldParentPtr *instruction) {
+    fprintf(irp->f, "@fieldParentPtr(");
+    ir_print_other_instruction(irp, instruction->type_value);
+    fprintf(irp->f, ",");
+    ir_print_other_instruction(irp, instruction->field_name);
+    fprintf(irp->f, ",");
+    ir_print_other_instruction(irp, instruction->field_ptr);
+    fprintf(irp->f, ")");
+}
+
 static void ir_print_instruction(IrPrint *irp, IrInstruction *instruction) {
     ir_print_prefix(irp, instruction);
     switch (instruction->id) {
@@ -1162,6 +1172,9 @@ static void ir_print_instruction(IrPrint *irp, IrInstruction *instruction) {
         case IrInstructionIdSetFnRefInline:
             ir_print_set_fn_ref_inline(irp, (IrInstructionSetFnRefInline *)instruction);
             break;
+        case IrInstructionIdFieldParentPtr:
+            ir_print_field_parent_ptr(irp, (IrInstructionFieldParentPtr *)instruction);
+            break;
     }
     fprintf(irp->f, "\n");
 }
diff --git a/std/build.zig b/std/build.zig
index ad42caa506..ca3cb6554a 100644
--- a/std/build.zig
+++ b/std/build.zig
@@ -580,9 +580,7 @@ const Exe = struct {
     }
 
     fn make(step: &Step) -> %void {
-        // TODO issue #320
-        //const self = @fieldParentPtr(Exe, "step", step);
-        const exe = @ptrcast(&Exe, step);
+        const exe = @fieldParentPtr(Exe, "step", step);
         const builder = exe.builder;
 
         var zig_args = List([]const u8).init(builder.allocator);
@@ -754,9 +752,7 @@ const CLibrary = struct {
     }
 
     fn make(step: &Step) -> %void {
-        // TODO issue #320
-        //const self = @fieldParentPtr(CLibrary, "step", step);
-        const self = @ptrcast(&CLibrary, step);
+        const self = @fieldParentPtr(CLibrary, "step", step);
         const cc = os.getEnv("CC") ?? "cc";
         const builder = self.builder;
 
@@ -897,9 +893,7 @@ const CExecutable = struct {
     }
 
     fn make(step: &Step) -> %void {
-        // TODO issue #320
-        //const self = @fieldParentPtr(CExecutable, "step", step);
-        const self = @ptrcast(&CExecutable, step);
+        const self = @fieldParentPtr(CExecutable, "step", step);
         const cc = os.getEnv("CC") ?? "cc";
         const builder = self.builder;
 
@@ -987,9 +981,7 @@ const CommandStep = struct {
     }
 
     fn make(step: &Step) -> %void {
-        // TODO issue #320
-        //const self = @fieldParentPtr(CExecutable, "step", step);
-        const self = @ptrcast(&CommandStep, step);
+        const self = @fieldParentPtr(CommandStep, "step", step);
 
         // TODO set cwd
         self.builder.spawnChildEnvMap(self.env_map, self.exe_path, self.args);
@@ -1021,9 +1013,7 @@ const InstallCLibraryStep = struct {
     }
 
     fn make(step: &Step) -> %void {
-        // TODO issue #320
-        //const self = @fieldParentPtr(InstallCLibraryStep, "step", step);
-        const self = @ptrcast(&InstallCLibraryStep, step);
+        const self = @fieldParentPtr(InstallCLibraryStep, "step", step);
 
         self.builder.copyFile(self.lib.out_filename, self.dest_file);
         if (!self.lib.static) {
@@ -1051,9 +1041,7 @@ const InstallFileStep = struct {
     }
 
     fn make(step: &Step) -> %void {
-        // TODO issue #320
-        //const self = @fieldParentPtr(InstallFileStep, "step", step);
-        const self = @ptrcast(&InstallFileStep, step);
+        const self = @fieldParentPtr(InstallFileStep, "step", step);
 
         debug.panic("TODO install file");
     }
diff --git a/std/mem.zig b/std/mem.zig
index e5b05071e9..99bfb0adee 100644
--- a/std/mem.zig
+++ b/std/mem.zig
@@ -76,9 +76,7 @@ pub const IncrementingAllocator = struct {
     }
 
     fn alloc(allocator: &Allocator, n: usize) -> %[]u8 {
-        // TODO issue #320
-        //const self = @fieldParentPtr(IncrementingAllocator, "allocator", allocator);
-        const self = @ptrcast(&IncrementingAllocator, allocator);
+        const self = @fieldParentPtr(IncrementingAllocator, "allocator", allocator);
         const new_end_index = self.end_index + n;
         if (new_end_index > self.bytes.len) {
             return error.NoMem;
diff --git a/test/cases/field_parent_ptr.zig b/test/cases/field_parent_ptr.zig
new file mode 100644
index 0000000000..fcb5c544a3
--- /dev/null
+++ b/test/cases/field_parent_ptr.zig
@@ -0,0 +1,41 @@
+const assert = @import("std").debug.assert;
+
+test "@fieldParentPtr non-first field" {
+    testParentFieldPtr(&foo.c);
+    comptime testParentFieldPtr(&foo.c);
+}
+
+test "@fieldParentPtr first field" {
+    testParentFieldPtrFirst(&foo.a);
+    comptime testParentFieldPtrFirst(&foo.a);
+}
+
+const Foo = struct {
+    a: bool,
+    b: f32,
+    c: i32,
+    d: i32,
+};
+
+const foo = Foo {
+    .a = true,
+    .b = 0.123,
+    .c = 1234,
+    .d = -10,
+};
+
+fn testParentFieldPtr(c: &const i32) {
+    assert(c == &foo.c);
+
+    const base = @fieldParentPtr(Foo, "c", c);
+    assert(base == &foo);
+    assert(&base.c == c);
+}
+
+fn testParentFieldPtrFirst(a: &const bool) {
+    assert(a == &foo.a);
+
+    const base = @fieldParentPtr(Foo, "a", a);
+    assert(base == &foo);
+    assert(&base.a == a);
+}
diff --git a/test/run_tests.cpp b/test/run_tests.cpp
index f928b05e87..e7b041ee3f 100644
--- a/test/run_tests.cpp
+++ b/test/run_tests.cpp
@@ -1902,6 +1902,56 @@ export fn foo() {
     var y: &void = @intToPtr(&void, x);
 }
     )SOURCE", 1, ".tmp_source.zig:4:31: error: type '&void' has 0 bits and cannot store information");
+
+    add_compile_fail_case("@fieldParentPtr - non struct", R"SOURCE(
+const Foo = i32;
+export fn foo(a: &i32) -> &Foo {
+    return @fieldParentPtr(Foo, "a", a);
+}
+    )SOURCE", 1, ".tmp_source.zig:4:28: error: expected struct type, found 'i32'");
+
+    add_compile_fail_case("@fieldParentPtr - bad field name", R"SOURCE(
+const Foo = struct {
+    derp: i32,
+};
+export fn foo(a: &i32) -> &Foo {
+    return @fieldParentPtr(Foo, "a", a);
+}
+    )SOURCE", 1, ".tmp_source.zig:6:33: error: struct 'Foo' has no field 'a'");
+
+    add_compile_fail_case("@fieldParentPtr - field pointer is not pointer", R"SOURCE(
+const Foo = struct {
+    a: i32,
+};
+export fn foo(a: i32) -> &Foo {
+    return @fieldParentPtr(Foo, "a", a);
+}
+    )SOURCE", 1, ".tmp_source.zig:6:38: error: expected pointer, found 'i32'");
+
+    add_compile_fail_case("@fieldParentPtr - comptime field ptr not based on struct", R"SOURCE(
+const Foo = struct {
+    a: i32,
+    b: i32,
+};
+const foo = Foo { .a = 1, .b = 2, };
+
+comptime {
+    const field_ptr = @intToPtr(&i32, 0x1234);
+    const another_foo_ptr = @fieldParentPtr(Foo, "b", field_ptr);
+}
+    )SOURCE", 1, ".tmp_source.zig:10:55: error: pointer value not based on parent struct");
+
+    add_compile_fail_case("@fieldParentPtr - comptime wrong field index", R"SOURCE(
+const Foo = struct {
+    a: i32,
+    b: i32,
+};
+const foo = Foo { .a = 1, .b = 2, };
+
+comptime {
+    const another_foo_ptr = @fieldParentPtr(Foo, "b", &foo.a);
+}
+    )SOURCE", 1, ".tmp_source.zig:9:29: error: field 'b' has index 1 but pointer value is index 0 of struct 'Foo'");
 }
 
 //////////////////////////////////////////////////////////////////////////////
diff --git a/test/self_hosted.zig b/test/self_hosted.zig
index 1ffdfbc459..98d0277f78 100644
--- a/test/self_hosted.zig
+++ b/test/self_hosted.zig
@@ -10,6 +10,7 @@ comptime {
     _ = @import("cases/enum_with_members.zig");
     _ = @import("cases/error.zig");
     _ = @import("cases/eval.zig");
+    _ = @import("cases/field_parent_ptr.zig");
     _ = @import("cases/fn.zig");
     _ = @import("cases/for.zig");
     _ = @import("cases/generics.zig");