From 1139f38e798181572121657e5b267a9698edb62f Mon Sep 17 00:00:00 2001 From: Jeff Law Date: Tue, 7 May 2024 11:43:09 -0600 Subject: [RISC-V] [PATCH v2] Enable inlining str* by default So with Chrstoph's patches from late 2022 we've had the ability to inline strlen, and str[n]cmp (scalar). However, we never actually turned this capability on by default! This patch flips the those default to allow inlinining by default. It also fixes one bug exposed by our internal testing when NBYTES is zero for strncmp. I don't think that case happens enough to try and optimize it, we just disable inline expansion for that instance. This has been bootstrapped and regression tested on rv64gc at various times as well as cross tested on rv64gc more times than I can probably count (we've have this patch internally for a while). More importantly, I just successfully tested it on rv64gc and rv32gcv elf configurations with the trunk gcc/ * config/riscv/riscv-string.cc (riscv_expand_strcmp): Do not inline strncmp with zero size. (emit_strcmp_scalar_compare_subword): Adjust rotation for rv32 vs rv64. * config/riscv/riscv.opt (var_inline_strcmp): Enable by default. (vriscv_inline_strncmp, riscv_inline_strlen): Likewise. gcc/testsuite * gcc.target/riscv/zbb-strlen-disabled-2.c: Turn off inlining. --- gcc/config/riscv/riscv-string.cc | 9 ++++++++- gcc/config/riscv/riscv.opt | 6 +++--- gcc/testsuite/gcc.target/riscv/zbb-strlen-disabled-2.c | 4 ++-- 3 files changed, 13 insertions(+), 6 deletions(-) (limited to 'gcc') diff --git a/gcc/config/riscv/riscv-string.cc b/gcc/config/riscv/riscv-string.cc index b09b51d..41cb061 100644 --- a/gcc/config/riscv/riscv-string.cc +++ b/gcc/config/riscv/riscv-string.cc @@ -153,7 +153,7 @@ emit_strcmp_scalar_compare_subword (rtx data1, rtx data2, rtx orc1, rtx imask = gen_rtx_CONST_INT (Xmode, im); rtx m_reg = gen_reg_rtx (Xmode); emit_insn (gen_rtx_SET (m_reg, imask)); - do_rotr3 (m_reg, m_reg, GEN_INT (64 - cmp_bytes * BITS_PER_UNIT)); + do_rotr3 (m_reg, m_reg, GEN_INT (BITS_PER_WORD - cmp_bytes * BITS_PER_UNIT)); do_and3 (data1, m_reg, data1); do_and3 (data2, m_reg, data2); if (TARGET_ZBB) @@ -497,6 +497,13 @@ riscv_expand_strcmp (rtx result, rtx src1, rtx src2, return false; nbytes = UINTVAL (bytes_rtx); + /* If NBYTES is zero the result of strncmp will always be zero, + but that would require special casing in the caller. So for + now just don't do an inline expansion. This probably rarely + happens in practice, but it is tested by the testsuite. */ + if (nbytes == 0) + return false; + /* We don't emit parts of a strncmp() call. */ if (nbytes > compare_max) return false; diff --git a/gcc/config/riscv/riscv.opt b/gcc/config/riscv/riscv.opt index 7cca1c4..1252834 100644 --- a/gcc/config/riscv/riscv.opt +++ b/gcc/config/riscv/riscv.opt @@ -517,15 +517,15 @@ Target Var(TARGET_INLINE_SUBWORD_ATOMIC) Init(1) Always inline subword atomic operations. minline-strcmp -Target Var(riscv_inline_strcmp) Init(0) +Target Var(riscv_inline_strcmp) Init(1) Inline strcmp calls if possible. minline-strncmp -Target Var(riscv_inline_strncmp) Init(0) +Target Var(riscv_inline_strncmp) Init(1) Inline strncmp calls if possible. minline-strlen -Target Var(riscv_inline_strlen) Init(0) +Target Var(riscv_inline_strlen) Init(1) Inline strlen calls if possible. -param=riscv-strcmp-inline-limit= diff --git a/gcc/testsuite/gcc.target/riscv/zbb-strlen-disabled-2.c b/gcc/testsuite/gcc.target/riscv/zbb-strlen-disabled-2.c index a481068..1295aeb 100644 --- a/gcc/testsuite/gcc.target/riscv/zbb-strlen-disabled-2.c +++ b/gcc/testsuite/gcc.target/riscv/zbb-strlen-disabled-2.c @@ -1,6 +1,6 @@ /* { dg-do compile } */ -/* { dg-options "-march=rv32gc_zbb" { target { rv32 } } } */ -/* { dg-options "-march=rv64gc_zbb" { target { rv64 } } } */ +/* { dg-options "-mno-inline-strlen -march=rv32gc_zbb" { target { rv32 } } } */ +/* { dg-options "-mno-inline-strlen -march=rv64gc_zbb" { target { rv64 } } } */ /* { dg-skip-if "" { *-*-* } { "-O0" "-Os" "-Og" "-Oz" } } */ typedef long unsigned int size_t; -- cgit v1.1