This is similar to http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54579 but for a different (and perhaps clearer) idiom for arithmetic shift right.  I've filed this as a separate PR rather than adding it as a comment, but if it's actually the same issue underneath, please merge or mark as a duplicate.

int asr(int a, int b)
{
  return a < 0 ? ~((~a) >> b) : a >> b;
}

olly@gcc12:~$ /opt/cfarm/gcc-latest/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/opt/cfarm/gcc-latest/bin/gcc
COLLECT_LTO_WRAPPER=/home/iulius/autobuild/bin/gcc-4.7.1/libexec/gcc/x86_64-unknown-linux-gnu/4.7.1/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-4.7.1-src/configure --prefix=/home/iulius/autobuild/bin/gcc-4.7.1 --with-gmp=/home/iulius/autobuild/bin/gmp-5.0.5 --with-mpfr=/home/iulius/autobuild/bin/mpfr-3.1.0 --with-mpc=/home/iulius/autobuild/bin/mpc-0.9 --disable-nls --enable-threads=posix --disable-multilib --enable-languages=c,c++
Thread model: posix
gcc version 4.7.1 (GCC) 

Compiling with:

LD_LIBRARY_PATH=/opt/cfarm/mpc-latest/lib:/opt/cfarm/mpfr-latest/lib:/opt/cfarm/gmp-latest/lib /opt/cfarm/gcc-latest/bin/gcc -O2 -S asr.c -o asr.S

Gives this for the function asr:

asr:
.LFB0:
	movl	%edi, %eax
	movl	%esi, %ecx
	sarl	%cl, %eax
	testl	%edi, %edi
	js	.L5
	rep
	ret
	.p2align 4,,10
	.p2align 3
.L5:
	movl	%edi, %eax
	notl	%eax
	sarl	%cl, %eax
	notl	%eax
	ret

Ideally the conditional would be optimised down to just the sarl instruction.

I've checked the older compiler versions on gcc12 (back to 4.1.1) and they all leave the branch in.  So if this is a regression, it isn't at all recent.