From aae873c0449dc67995d02ce9f1e65b2c49065888 Mon Sep 17 00:00:00 2001
From: Zack Puhl <github@xmit.xyz>
Date: Wed, 6 Aug 2025 07:55:39 -0400
Subject: [PATCH] Add `bitsizeof` to Builtins (#2376)

* Add `bitsizeof` to Builtins

---------

Co-authored-by: Christoffer Lerno <christoffer@aegik.com>
---
 lib/std/core/builtin.c3               |  4 ++++
 releasenotes.md                       |  1 +
 test/unit/stdlib/core/builtintests.c3 | 19 +++++++++++++++++++
 3 files changed, 24 insertions(+)

diff --git a/lib/std/core/builtin.c3 b/lib/std/core/builtin.c3
index da19078dc..0c963159a 100644
--- a/lib/std/core/builtin.c3
+++ b/lib/std/core/builtin.c3
@@ -89,6 +89,10 @@ macro void @swap(#a, #b) @builtin
 	#b = temp;
 }
 
+macro usz bitsizeof($Type) @builtin @const => $Type.sizeof * 8u;
+
+macro usz @bitsizeof(#expr) @builtin @const => $sizeof(#expr) * 8u;
+
 <*
  Convert an `any` type to a type, returning an failure if there is a type mismatch.
 
diff --git a/releasenotes.md b/releasenotes.md
index 5bce9ba3b..4c7eff823 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -6,6 +6,7 @@
 - Support `alias foo = module std::io` module aliasing.
 - Add compile-time `@intlog2` macro to math.
 - Add compile-time `@clz` builtin. #2367
+- Add `bitsizeof` macro builtins. #2376
 
 ### Fixes
 - List.remove_at would incorrectly trigger ASAN.
diff --git a/test/unit/stdlib/core/builtintests.c3 b/test/unit/stdlib/core/builtintests.c3
index 436d6b77f..6f436a6ed 100644
--- a/test/unit/stdlib/core/builtintests.c3
+++ b/test/unit/stdlib/core/builtintests.c3
@@ -184,3 +184,22 @@ fn void test_ct_clz()
 	assert(@clz((uint128)0x87) == 120);
 	assert(@clz((char)(0x44 - 0x40)) == 5);
 }
+
+fn void test_bitsizeof()
+{
+	assert(bitsizeof(uint128) == 128);
+	assert(bitsizeof(ulong) == 64);
+	assert(bitsizeof(int) == 32);
+	assert(bitsizeof(short) == 16);
+	assert(bitsizeof(char) == 8);
+	assert(bitsizeof(char[200]) == 1600);
+
+	// Checks that they may be converted
+	int x = bitsizeof(char);
+	int y = @bitsizeof(1);
+
+	assert(@bitsizeof((char)0x07) == 8);
+	assert(@bitsizeof(0x1000ul) == 64);
+	assert(@bitsizeof(0) == 32);
+	assert(@bitsizeof((char[*])"abcdefghi") == 72);
+}
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