From 0c5e64c4249322a178e1a0e843874e4d6b43b992 Mon Sep 17 00:00:00 2001 From: Lin Sinan Date: Tue, 11 Apr 2023 10:23:19 -0600 Subject: [PATCH] RISC-V: avoid splitting small constant in i_extrabit pattern 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. --- gcc/config/riscv/predicates.md | 2 +- gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c | 14 ++++++++++++++ 2 files changed, 15 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c diff --git a/gcc/config/riscv/predicates.md b/gcc/config/riscv/predicates.md index 0d9d770..8654dbc 100644 --- a/gcc/config/riscv/predicates.md +++ b/gcc/config/riscv/predicates.md @@ -399,7 +399,7 @@ (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 diff --git a/gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c b/gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c new file mode 100644 index 0000000..ef7ed60 --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c @@ -0,0 +1,14 @@ +/* { 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 } } */ -- 2.7.4