[clang] FEAT: one byte for "true" & "false" (PR #138649)
https://github.com/saksham-joshi updated https://github.com/llvm/llvm-project/pull/138649 >From 8bba07d817d4dd583122d7ed831de276da8801e0 Mon Sep 17 00:00:00 2001 From: SAKSHAM JOSHI Date: Tue, 6 May 2025 12:43:34 +0530 Subject: [PATCH] FEAT: one byte for "true" & "false" In C programming language, The size of "true" and "false" macros is 4 byte and size of "_Bool" datatype is 1 byte. By this simple change, we can set the size of "true" and "false" to 1 byte. --- clang/lib/Headers/stdbool.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/clang/lib/Headers/stdbool.h b/clang/lib/Headers/stdbool.h index dfaad2b65a9b5..e9142327f0ffd 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 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] FEAT: one byte for "true" & "false" (PR #138649)
https://github.com/saksham-joshi created https://github.com/llvm/llvm-project/pull/138649 ### 1 byte is enough for bool - In C programming language, - the size of **"true"** and **"false"** macros is 4 byte and size of macro "bool" (typedef of _Bool) is 1 byte. - By this simple change, we can set the size of "true" and "false" to 1 byte. - This change will decrease the memory usage made by using true & false macros in C. >From 8bba07d817d4dd583122d7ed831de276da8801e0 Mon Sep 17 00:00:00 2001 From: SAKSHAM JOSHI Date: Tue, 6 May 2025 12:43:34 +0530 Subject: [PATCH] FEAT: one byte for "true" & "false" In C programming language, The size of "true" and "false" macros is 4 byte and size of "_Bool" datatype is 1 byte. By this simple change, we can set the size of "true" and "false" to 1 byte. --- clang/lib/Headers/stdbool.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/clang/lib/Headers/stdbool.h b/clang/lib/Headers/stdbool.h index dfaad2b65a9b5..e9142327f0ffd 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 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] FEAT: one byte for "true" & "false" (PR #138649)
https://github.com/saksham-joshi updated https://github.com/llvm/llvm-project/pull/138649 >From 8bba07d817d4dd583122d7ed831de276da8801e0 Mon Sep 17 00:00:00 2001 From: SAKSHAM JOSHI Date: Tue, 6 May 2025 12:43:34 +0530 Subject: [PATCH 1/2] FEAT: one byte for "true" & "false" In C programming language, The size of "true" and "false" macros is 4 byte and size of "_Bool" datatype is 1 byte. By this simple change, we can set the size of "true" and "false" to 1 byte. --- clang/lib/Headers/stdbool.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/clang/lib/Headers/stdbool.h b/clang/lib/Headers/stdbool.h index dfaad2b65a9b5..e9142327f0ffd 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 >From 890f5b7cb698fe6ae167247ff6453940b8f71af9 Mon Sep 17 00:00:00 2001 From: SAKSHAM JOSHI Date: Tue, 6 May 2025 21:24:03 +0530 Subject: [PATCH 2/2] Update stdbool.h --- clang/lib/Headers/stdbool.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/clang/lib/Headers/stdbool.h b/clang/lib/Headers/stdbool.h index e9142327f0ffd..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 (bool)1 -#define false (bool)0 +#define true ((bool)1) +#define false ((bool)0) #elif defined(__GNUC__) && !defined(__STRICT_ANSI__) /* Define _Bool as a GNU extension. */ #define _Bool bool ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] FEAT: one byte for "true" & "false" (PR #138649)
https://github.com/saksham-joshi updated
https://github.com/llvm/llvm-project/pull/138649
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[clang] FEAT: 1 byte for "true" & "false" (PR #138713)
https://github.com/saksham-joshi created https://github.com/llvm/llvm-project/pull/138713 # 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. >From db8d4b5b102c9e1cf8d43d108858ede66baea82f Mon Sep 17 00:00:00 2001 From: SAKSHAM JOSHI Date: Tue, 6 May 2025 21:37:08 +0530 Subject: [PATCH] FEAT: 1 byte for "true" & "false" - 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. --- clang/lib/Headers/stdbool.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) 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 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] FEAT: one byte for "true" & "false" (PR #138649)
https://github.com/saksham-joshi updated https://github.com/llvm/llvm-project/pull/138649 >From 8bba07d817d4dd583122d7ed831de276da8801e0 Mon Sep 17 00:00:00 2001 From: SAKSHAM JOSHI Date: Tue, 6 May 2025 12:43:34 +0530 Subject: [PATCH 1/3] FEAT: one byte for "true" & "false" In C programming language, The size of "true" and "false" macros is 4 byte and size of "_Bool" datatype is 1 byte. By this simple change, we can set the size of "true" and "false" to 1 byte. --- clang/lib/Headers/stdbool.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/clang/lib/Headers/stdbool.h b/clang/lib/Headers/stdbool.h index dfaad2b65a9b5..e9142327f0ffd 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 >From 890f5b7cb698fe6ae167247ff6453940b8f71af9 Mon Sep 17 00:00:00 2001 From: SAKSHAM JOSHI Date: Tue, 6 May 2025 21:24:03 +0530 Subject: [PATCH 2/3] Update stdbool.h --- clang/lib/Headers/stdbool.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/clang/lib/Headers/stdbool.h b/clang/lib/Headers/stdbool.h index e9142327f0ffd..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 (bool)1 -#define false (bool)0 +#define true ((bool)1) +#define false ((bool)0) #elif defined(__GNUC__) && !defined(__STRICT_ANSI__) /* Define _Bool as a GNU extension. */ #define _Bool bool >From 1ad7042ac9c09aa7274c9c40084fc496b5ed93a4 Mon Sep 17 00:00:00 2001 From: SAKSHAM JOSHI Date: Wed, 7 May 2025 07:40:16 +0530 Subject: [PATCH 3/3] FEAT: 1 byte for "true" & "false" 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. --- clang/lib/Headers/stdbool.h | 6 -- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/clang/lib/Headers/stdbool.h b/clang/lib/Headers/stdbool.h index 4b81e4ba820d1..0aa017e58c3c7 100644 --- a/clang/lib/Headers/stdbool.h +++ b/clang/lib/Headers/stdbool.h @@ -22,8 +22,10 @@ */ #elif !defined(__cplusplus) #define bool _Bool -#define true ((bool)1) -#define false ((bool)0) +#define true 1 +#define false 0 +#define true_1 ((bool)1) +#define false_1 ((bool)0) #elif defined(__GNUC__) && !defined(__STRICT_ANSI__) /* Define _Bool as a GNU extension. */ #define _Bool bool ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] FEAT: one byte for "true" & "false" (PR #138649)
https://github.com/saksham-joshi closed https://github.com/llvm/llvm-project/pull/138649 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] FEAT: 1 byte for "true" & "false" (PR #138713)
https://github.com/saksham-joshi closed https://github.com/llvm/llvm-project/pull/138713 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] FEAT: 1 byte for "true" & "false" (PR #138713)
saksham-joshi wrote:
> > Yeah! you are right that the size depends on the variable, but I never said
> > to create a variable.
> > Suppose I have two functions performing same process but one is returning
> > bool and other one is returning int.
> >
> > 1. bool fnc1() { return (_Bool)true; }
> > 2. int fnc2(){ return true; }
> >
> > Can you please tell me which of the above 2 function will be more efficient?
>
> Again, in this case the "efficiency" of these functions does not depend on
> how you declare true and false, but rather on what return type each function
> has.
>
> But the impact of type change is also questionable. Per modern calling
> conventions, the return value of a function is stored in a CPU register, and
> the size of that register is usually 4 or 8 bytes. Even if one decides to
> return a 1-byte value, there won't be much difference for the CPU. (Well, on
> x86 you can return the 1-byte value in AL, but this won't lead to faster
> code).
>
> > If this is also the case with Clang, then my work is done here.
>
> Yes, this is also the case.
Okay, I got it!
Thank you so much Mr. Ramosian Glider
https://github.com/llvm/llvm-project/pull/138713
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