On 11/28/24 5:26 AM, Alexey Merzlyakov wrote:
This patch adds optimization of the following patterns:
(zero_extend:M (subreg:N (not:O==M (X:Q==M)))) ->
(xor:M (zero_extend:M (subreg:N (X:M)), mask))
... where the mask is GET_MODE_MASK (N).
For the cases when X:M doesn't have any non-zero bits outside of mode N,
(zero_extend:M (subreg:N (X:M)) could be simplified to just (X:M)
and whole optimization will be:
(zero_extend:M (subreg:N (not:M (X:M)))) ->
(xor:M (X:M, mask))
Patch targets to handle code patterns like:
not a0,a0
andi a0,a0,0xff
to be optimized to:
xori a0,a0,255
PR rtl-optimization/112398
PR rtl-optimization/117476
gcc/ChangeLog:
* simplify-rtx.cc (simplify_context::simplify_unary_operation_1):
Simplify ZERO_EXTEND (SUBREG (NOT X)) to XOR (X, GET_MODE_MASK(SUBREG))
when X doesn't have any non-zero bits outside of SUBREG mode.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/pr112398.c: New test.
* gcc.dg/torture/pr117476-1.c: New test. From Zhendong Su.
* gcc.dg/torture/pr117476-2.c: New test. From Zdenek Sojka.
Thanks. I've bootstrapped & regression tested this on x86_64 as well as
run it through my tester successfully. Pushed to the trunk. Hopefully
no fallout this time :-)
jeff
