On 6/4/24 10:22 PM, liuhongt wrote:
Can you add a testcase for this? I don't mind if it's x86 specific and
does a bit of asm scanning.
Also note that the context for this patch has changed, so it won't
automatically apply. So be extra careful when updating so that it goes
into the right place (all the more reason to have a testcase validating
that the optimization works correctly).
I think the patch itself is fine. So further review is just for the
testcase and should be easy.
rebased and add a testcase.
Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
Ok for trunk?
When mask is (1 << (prec - imm) - 1) which is used to clear upper bits
of A, then it can be simplified to LSHIFTRT.
i.e Simplify
(and:v8hi
(ashifrt:v8hi A 8)
(const_vector 0xff x8))
to
(lshifrt:v8hi A 8)
gcc/ChangeLog:
PR target/114428
* simplify-rtx.cc
(simplify_context::simplify_binary_operation_1):
Simplify (AND (ASHIFTRT A imm) mask) to (LSHIFTRT A imm) for
specific mask.
gcc/testsuite/ChangeLog:
* gcc.target/i386/pr114428-1.c: New test.
OK.
Being x264 related, I took a quick glance at RISC-V before/after and
seems to be slightly better as well.
Jeff
