Re: Deprecation of i386 and 32-bit powerpc for 15.0 [ an aarch64/armv7 context note for -m32 ]

Konstantin Belousov <kostikbel_at_gmail.com> wrote on
Date: Sun, 22 Jun 2025 02:55:15 UTC :

> On Sat, Jun 21, 2025 at 06:39:03PM -0700, Rodney W. Grimes wrote:
> > . . .
> 
> The i386 world on amd64 kernel is the supported configuration, and I
> will put the efforts to keep this going. Simultaneously, there is not
> much value in the full world for i386, lib32 + cc -m32 is the most
> interesting thing for me and perhaps, practically, for all other people
> who really use 32bit (as opposed to use it for flaming on ml).
> 
> . . .

In this area, but for aarch64/armv7 instead of amd64/i386:

# cc -v -m32 basic_double_use.c

in an aarch64 context reports using:

"/usr/bin/cc" -cc1 -triple armv4t-unknown-freebsd15.0

So: not armv7 and no -gnueabihf

The context has:

# cc -v
FreeBSD clang version 19.1.7 (https://github.com/llvm/llvm-project.git llvmorg-19.1.7-0-gcd708029e0b2)
Target: aarch64-unknown-freebsd15.0
Thread model: posix
InstalledDir: /usr/bin
Build config: +assertions

By contrast, in an armv7 context:

# cc -v
FreeBSD clang version 19.1.7 (https://github.com/llvm/llvm-project.git llvmorg-19.1.7-0-gcd708029e0b2)
Target: armv7-unknown-freebsd15.0-gnueabihf
Thread model: posix
InstalledDir: /usr/bin
Build config: +assertions

But . . .

# cc -v -m32 basic_double_use.c

reports using:

"/usr/bin/cc" -cc1 -triple armv7-unknown-freebsd15.0-gnueabihf . . .

as expected: armv7 and -gnueabihf in use. 

Thus on aarch64, one needs to be explicit about -target ,
unlike on armv7:

# cc -v -m32 -target armv7-unknown-freebsd15.0-gnueabihf basic_double_use.c

reports using:

"/usr/bin/cc" -cc1 -triple armv7-unknown-freebsd15.0-gnueabihf

In summary: -m32 ends up with the wrong default -target
for the modern aarch64 FreeBSD type of context.


For reference:

# cat basic_double_use.c
int main(void)
{
    volatile double a=10;
    volatile double b=13;
    return (a*b<b/a) ? 0 : 1;
}


I've updated https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=272806
with a version of these notes, as they should be clearer than my
original submittal for the issue.


===
Mark Millard
marklmi at yahoo.com