On 5/8/24 1:36 AM, Christoph Müllner wrote:
The lshr<GPR:mode>3_zero_extend_4 pattern targets bit extraction
with zero-extension. This pattern represents the canonical form
of zero-extensions of a logical right shift.
The same optimization can be applied to sign-extensions.
Given the two optimizations are so similar, this patch converts
the existing one to also cover the sign-extension case as well.
gcc/ChangeLog:
* config/riscv/iterators.md (ashiftrt): New code attribute
'extract_shift' and adding extractions to optab.
* config/riscv/riscv.md (*lshr<GPR:mode>3_zero_extend_4): Rename to...
(*<any_extract:optab><GPR:mode>3):...this and add support for
sign-extensions.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/extend-shift-helpers.h: Add helpers for
sign-extension.
* gcc.target/riscv/sign-extend-rshift-32.c: New test.
* gcc.target/riscv/sign-extend-rshift-64.c: New test.
* gcc.target/riscv/sign-extend-rshift.c: New test.
Oh, I see, you handled the special case with this patch. Ignore my
comment on 3/4. 3/4 is fine, as is this patch.
Thanks!
jeff
