From 59dfce6d618ccf5865dec216603dbc25a4f7bf2d Mon Sep 17 00:00:00 2001 From: Jeff Law Date: Sun, 16 Jun 2024 08:36:27 -0600 Subject: [PATCH] [to-be-committed] [RISC-V] Improve (1 << N) | C for rv64 Another improvement for generating Zbs instructions. In this case we're looking at stuff like (1 << N) | C where N varies and C is a single bit constant. In this pattern the (1 << N) happens in SImode, but is zero extended out to DImode before the bit manipulation. The fact that we're modifying a DImode object in the logical op is important as it means we don't have to worry about whether or not the resulting value is sign extended from SI to DI. This has run through Ventana's CI system. I'll wait for it to roll through pre-commit CI before moving forward. gcc/ * config/riscv/bitmanip.md ((1 << N) | C): New splitter for IOR/XOR of a single bit an a DImode object. gcc/testsuite/ * gcc.target/riscv/zbs-zext.c: New test. --- gcc/config/riscv/bitmanip.md | 15 +++++++++++ gcc/testsuite/gcc.target/riscv/zbs-zext.c | 31 +++++++++++++++++++++++ 2 files changed, 46 insertions(+) create mode 100644 gcc/testsuite/gcc.target/riscv/zbs-zext.c diff --git a/gcc/config/riscv/bitmanip.md b/gcc/config/riscv/bitmanip.md index 4ee413c143e3..0d35fb786e11 100644 --- a/gcc/config/riscv/bitmanip.md +++ b/gcc/config/riscv/bitmanip.md @@ -627,6 +627,21 @@ "bseti\t%0,%1,%S2" [(set_attr "type" "bitmanip")]) +;; We can easily handle zero extensions +(define_split + [(set (match_operand:DI 0 "register_operand") + (any_or:DI (zero_extend:DI + (ashift:SI (const_int 1) + (match_operand:QI 1 "register_operand"))) + (match_operand:DI 2 "single_bit_mask_operand"))) + (clobber (match_operand:DI 3 "register_operand"))] + "TARGET_64BIT && TARGET_ZBS" + [(set (match_dup 3) + (match_dup 2)) + (set (match_dup 0) + (any_or:DI (ashift:DI (const_int 1) (match_dup 1)) + (match_dup 3)))]) + (define_insn "*bclr" [(set (match_operand:X 0 "register_operand" "=r") (and:X (rotate:X (const_int -2) diff --git a/gcc/testsuite/gcc.target/riscv/zbs-zext.c b/gcc/testsuite/gcc.target/riscv/zbs-zext.c new file mode 100644 index 000000000000..5773b15d2987 --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/zbs-zext.c @@ -0,0 +1,31 @@ +/* { dg-do compile } */ +/* { dg-options "-march=rv64gc_zbs -mabi=lp64" } */ +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-O1" } } */ +typedef unsigned long uint64_t; +typedef unsigned int uint32_t; + +uint64_t bset (const uint32_t i) +{ + uint64_t checks = 8; + checks |= 1U << i; + return checks; +} + +uint64_t binv (const uint32_t i) +{ + uint64_t checks = 8; + checks ^= 1U << i; + return checks; +} + +uint64_t bclr (const uint32_t i) +{ + uint64_t checks = 10; + checks &= ~(1U << i); + return checks; +} + +/* { dg-final { scan-assembler-times "bset\t" 1 } } */ +/* { dg-final { scan-assembler-times "binv\t" 1 } } */ +/* { dg-final { scan-assembler-times "bclr\t" 1 } } */ +/* { dg-final { scan-assembler-not "sllw\t"} } */ -- 2.47.2