there is no need to split an xori/ori with an small constant. take the test
case `int foo(int idx) { return idx|3; }` as an example,
rv64im_zba generates:
ori a0,a0,3
ret
but, rv64im_zba_zbs generates:
ori a0,a0,1
ori a0,a0,2
ret
with this change, insn `ori r2,r1,3` will not be splitted in zbs.
gcc/
* config/riscv/predicates.md (uimm_extra_bit_or_twobits): Adjust
predicate to avoid splitting arith constants.
gcc/testsuite
* gcc.target/riscv/zbs-extra-bit-or-twobits.c: New test.
(define_predicate "uimm_extra_bit_or_twobits"
(and (match_code "const_int")
(ior (match_operand 0 "uimm_extra_bit_operand")
- (match_operand 0 "const_twobits_operand"))))
+ (match_operand 0 "const_twobits_not_arith_operand"))))
;; A CONST_INT operand that fits into the negative half of a
;; signed-immediate after a single cleared top bit has been
--- /dev/null
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gc_zbs -mabi=lp64" } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" } } */
+
+int or_two_bit(int idx) {
+ return idx|3;
+}
+
+int xor_two_bit(int idx) {
+ return idx^3;
+}
+
+/* { dg-final { scan-assembler-times "\tori\t" 1 } } */
+/* { dg-final { scan-assembler-times "\txori\t" 1 } } */