diff --git a/lib/compiler/Maker/WebServer.zig b/lib/compiler/Maker/WebServer.zig
index 943265c9397eb1ce20738171557e9f53134477c7..5191e6ab2d7465de8ff690afd2d904ce48ff6c50 100644
--- a/lib/compiler/Maker/WebServer.zig
+++ b/lib/compiler/Maker/WebServer.zig
@@ -876,8 +876,8 @@ pub fn updateTimeReportRunTest(
     assert(tests.names.len == ns_per_test.len);
     const tests_len: u32 = @intCast(tests.names.len);
 
-    const new_len: u64 = len: {
-        var names_len: u64 = 0;
+    const new_len: usize = len: {
+        var names_len: usize = 0;
         for (0..tests_len) |i| {
             names_len += tests.testName(@intCast(i)).len + 1;
         }
diff --git a/lib/std/Build.zig b/lib/std/Build.zig
index bc77290f131a15926eb9e561bd030658b91ce60c..6cbb820d96229d11f555d506317c54df170fe574 100644
--- a/lib/std/Build.zig
+++ b/lib/std/Build.zig
@@ -692,7 +692,7 @@ pub const ExecutableOptions = struct {
     root_module: *Module,
     version: ?std.SemanticVersion = null,
     linkage: ?std.builtin.LinkMode = null,
-    max_rss: usize = 0,
+    max_rss: u64 = 0,
     use_llvm: ?bool = null,
     use_lld: ?bool = null,
     zig_lib_dir: ?LazyPath = null,
@@ -722,7 +722,7 @@ pub fn addExecutable(b: *Build, options: ExecutableOptions) *Step.Compile {
 pub const ObjectOptions = struct {
     name: []const u8,
     root_module: *Module,
-    max_rss: usize = 0,
+    max_rss: u64 = 0,
     use_llvm: ?bool = null,
     use_lld: ?bool = null,
     zig_lib_dir: ?LazyPath = null,
@@ -745,7 +745,7 @@ pub const LibraryOptions = struct {
     name: []const u8,
     root_module: *Module,
     version: ?std.SemanticVersion = null,
-    max_rss: usize = 0,
+    max_rss: u64 = 0,
     use_llvm: ?bool = null,
     use_lld: ?bool = null,
     zig_lib_dir: ?LazyPath = null,
@@ -778,7 +778,7 @@ pub fn addLibrary(b: *Build, options: LibraryOptions) *Step.Compile {
 pub const TestOptions = struct {
     name: []const u8 = "test",
     root_module: *Module,
-    max_rss: usize = 0,
+    max_rss: u64 = 0,
     filters: []const []const u8 = &.{},
     test_runner: ?Step.Compile.TestRunner = null,
     use_llvm: ?bool = null,
@@ -819,7 +819,7 @@ pub const AssemblyOptions = struct {
     /// `host` field of the package's `Build` instance.
     target: ResolvedTarget,
     optimize: std.builtin.OptimizeMode,
-    max_rss: usize = 0,
+    max_rss: u64 = 0,
     zig_lib_dir: ?LazyPath = null,
 };
 
diff --git a/lib/std/Build/Step.zig b/lib/std/Build/Step.zig
index b35697a2a1bba5896737df3d4375d433934795fb..78c1e3343c23acec72985f2b9d357e52dc3b977f 100644
--- a/lib/std/Build/Step.zig
+++ b/lib/std/Build/Step.zig
@@ -30,7 +30,7 @@ dependencies: std.ArrayList(*Step),
 /// max_rss value that does not exceed the `max_total_rss` value of the build
 /// runner. This value is configurable on the command line, and defaults to the
 /// total system memory available.
-max_rss: usize,
+max_rss: u64,
 
 /// The return address associated with creation of this step that can be useful
 /// to print along with debugging messages.
@@ -87,7 +87,7 @@ pub const StepOptions = struct {
     name: []const u8,
     owner: *Build,
     first_ret_addr: ?usize = null,
-    max_rss: usize = 0,
+    max_rss: u64 = 0,
 };
 
 pub fn init(options: StepOptions) Step {
diff --git a/lib/std/Build/Step/Compile.zig b/lib/std/Build/Step/Compile.zig
index 448e3b0dde840fae5d42c2b194fc404b5eb01cd0..f61a55d9214ed096c793e29866cf96bfafab9057 100644
--- a/lib/std/Build/Step/Compile.zig
+++ b/lib/std/Build/Step/Compile.zig
@@ -269,7 +269,7 @@ pub const Options = struct {
     kind: Kind,
     linkage: ?std.builtin.LinkMode = null,
     version: ?std.SemanticVersion = null,
-    max_rss: usize = 0,
+    max_rss: u64 = 0,
     filters: []const []const u8 = &.{},
     test_runner: ?TestRunner = null,
     use_llvm: ?bool = null,
diff --git a/lib/std/elf.zig b/lib/std/elf.zig
index fcf5152a2b7ec8a12e9bddb954829d71f5e1bb5b..afcf236c28b4a0e4c0df14efde65620fcd4441e9 100644
--- a/lib/std/elf.zig
+++ b/lib/std/elf.zig
@@ -873,8 +873,8 @@ pub const ProgramHeaderBufferIterator = struct {
         if (it.index >= it.phnum) return null;
         defer it.index += 1;
 
-        const size: u64 = if (it.is_64) @sizeOf(Elf64_Phdr) else @sizeOf(Elf32_Phdr);
-        const offset = it.phoff + size * it.index;
+        const size: usize = if (it.is_64) @sizeOf(Elf64_Phdr) else @sizeOf(Elf32_Phdr);
+        const offset = @as(usize, @intCast(it.phoff)) + size * it.index;
         var reader = Io.Reader.fixed(it.buf[offset..]);
 
         return try takeProgramHeader(&reader, it.is_64, it.endian);
diff --git a/test/src/Libc.zig b/test/src/Libc.zig
index a7cb01c8252edf4ce8b10bab454f95913483a13c..d2113893325821c63a441eba99ea06f1a4610402 100644
--- a/test/src/Libc.zig
+++ b/test/src/Libc.zig
@@ -11,7 +11,7 @@ pub const Options = struct {
     test_filters: []const []const u8,
     test_target_filters: []const []const u8,
     skip_wasm: bool,
-    max_rss: usize,
+    max_rss: u64,
 };
 
 const TestCase = struct {
diff --git a/test/tests.zig b/test/tests.zig
index b88dc8e3c57edb1d09497e587dd17f0823e218c4..0bb1b942e72d6829fa5e25929b80118b4d2a7363 100644
--- a/test/tests.zig
+++ b/test/tests.zig
@@ -2467,7 +2467,7 @@ pub const ModuleTestOptions = struct {
     skip_linux: bool,
     skip_llvm: bool,
     skip_libc: bool,
-    max_rss: usize = 0,
+    max_rss: u64 = 0,
     no_builtin: bool = false,
     sanitize_thread: ?bool = null,
     build_options: ?*Step.Options = null,
@@ -2795,7 +2795,7 @@ const CAbiTestOptions = struct {
     skip_darwin: bool,
     skip_linux: bool,
     skip_llvm: bool,
-    max_rss: usize = 0,
+    max_rss: u64 = 0,
 };
 
 pub fn addCAbiTests(b: *std.Build, options: CAbiTestOptions) *Step {