compiler C++ compile times: Clang (bcc32c) vs. Borland (bcc32)

[Michaell 3]

I'm currently using C++ Builder Athens 12.2 and switched from bcc32 to bcc32c. Following my finding regarding the huge compile time differences. All values are rounded (max. +/- 3 s) and measured several times.

CPU Ryzen 5 5600X:

1. bcc32: 25 s, 1 CPU thread
2. bcc32c: around 40 minutes, 1 CPU thread
3. bcc32c: 170 s, 12 CPU threads

Due to this bad result I upgraded my CPU.

CPU Ryzen 9 5950X:

1. bcc32: not measured
2. bcc32c: 120 s, 12 CPU threads
3. bcc32c: 80 s, 32 CPU threads

May be these information may help other users in view of compiler switch and or CPU switch.

 

Greetings!

Michaell

Edited July 30 by Michaell
1 value more exact documented

[Lachlan Gemmell 33]

I don't use the Clang compiler but I do remember that Athens 12.3 was supposed to give it a decent speed boost. Might be worth you upgrading from 12.2 when you have some time.

[Michaell 3]

Thanks, I'm aware of the may be present performance gain of release 12.3. In case it is also for the not 64 bit compiler = bcc32c I will update this thread.

[Roger Cigol 135]

Are you using TwineCompile ? - for the 32 bit clang compiler this additional plug in (available FOC on getit) is virtually essential.

[Michaell 3]

On 8/13/2025 at 1:01 PM, Roger Cigol said:

Are you using TwineCompile ? ...

Thanks for this information. No, I'm not using it. Its website tells it is an extra cost of 139 $ (no issue) may be I will have a look on it. FYI: getit is no option, I'm working offline.

[hansw 4]

As you have a license for C++Builder 12.3 you can download TwineCompile from the Embarcadero Registered Products Portal. If you are working with project groups, then I would recommend to deactivate the TwineCompile option "Build projects in parallel".

[David P 5]

Clang batch compilation is almost as good as Twine in my experience:

 

   Project Options - Building - C++ Compiler - Geneal compilation  - Enable batch Compilation

 

plus

 

   Project Options - Project Properties - General - Run C++ Compiler in a separate Process. 

 

I have number of subprocesses set to 28.

 

Also 

 

   Tools - Options - Compiling and Running - Background compilation

[Roger Cigol 135]

18 hours ago, David P said:

Clang batch compilation is almost as good as Twine in my experience:

Does this statement apply to Clang32 compiler ? I believe your statement to (in general) be the case for clang64 but am less sure it applies to clang32.

[David P 5]

On 8/19/2025 at 9:54 AM, Roger Cigol said:

Does this statement apply to Clang32 compiler ? I believe your statement to (in general) be the case for clang64 but am less sure it applies to clang32.

Yes it does.  Our main project is a 32-bit Clang app and it compiles in the background, using 28 threads (on a PC with 32 logical processors).

 

In BCB2007, we used TC, but since using v10+ and changing to Clang, we have found the Clang compiler using the above settings to be on a par speedwise.

 

              

 

This is compiling a 32-bit Clang application just using Clang Batch/background compiling.

[Michaell 3]

As my initial post tells, I'm already using 32 threads. I.e. as far as the experience of David P is generally valid I have no reason to try TwineCompile.