[clang] FEAT: 1 byte for "true" & "false" (PR #138713)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: SAKSHAM JOSHI (saksham-joshi)

<details>
<summary>Changes</summary>

# In C language,

- the size of "true" and "false" macro is 4 bytes (for x64 arch)

- but the size of "bool" (typedef _Bool) is 1 byte.

- In order to decrease the memory usage, we can set the size of "true" and "false" macros to 1 byte using explicit typecasting in macro definition.

---
Full diff: https://github.com/llvm/llvm-project/pull/138713.diff


1 Files Affected:

- (modified) clang/lib/Headers/stdbool.h (+2-2) 


``````````diff
diff --git a/clang/lib/Headers/stdbool.h b/clang/lib/Headers/stdbool.h
index dfaad2b65a9b5..4b81e4ba820d1 100644
--- a/clang/lib/Headers/stdbool.h
+++ b/clang/lib/Headers/stdbool.h
@@ -22,8 +22,8 @@
  */
 #elif !defined(__cplusplus)
 #define bool _Bool
-#define true 1
-#define false 0
+#define true ((bool)1)
+#define false ((bool)0)
 #elif defined(__GNUC__) && !defined(__STRICT_ANSI__)
 /* Define _Bool as a GNU extension. */
 #define _Bool bool

``````````

</details>


https://github.com/llvm/llvm-project/pull/138713