From 0431e8ae5bdb854bda5f9005e41c8c4d03f6d74e Mon Sep 17 00:00:00 2001 From: Andre Vieira Date: Tue, 15 Nov 2022 09:50:39 +0000 Subject: [PATCH] aarch64: Enable the use of LDAPR for load-acquire semantics This patch enables the use of LDAPR for load-acquire semantics. 2022-11-15 Andre Vieira Kyrylo Tkachov gcc/ChangeLog: * config/aarch64/aarch64.h (AARCH64_ISA_RCPC): New Macro. (TARGET_RCPC): New Macro. * config/aarch64/atomics.md (atomic_load): Change into an expand. (aarch64_atomic_load_rcpc): New define_insn for ldapr. (aarch64_atomic_load): Rename of old define_insn for ldar. * config/aarch64/iterators.md (UNSPEC_LDAP): New unspec enum value. * doc/invoke.texi (rcpc): Ammend documentation to mention the effects on code generation. gcc/testsuite/ChangeLog: * gcc.target/aarch64/ldapr.c: New test. --- gcc/config/aarch64/aarch64.h | 4 ++++ gcc/config/aarch64/atomics.md | 33 ++++++++++++++++++++++++++++++- gcc/config/aarch64/iterators.md | 1 + gcc/doc/invoke.texi | 6 +++--- gcc/testsuite/gcc.target/aarch64/ldapr.c | 34 ++++++++++++++++++++++++++++++++ 5 files changed, 74 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/gcc.target/aarch64/ldapr.c diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h index bbbb7e4..070466d 100644 --- a/gcc/config/aarch64/aarch64.h +++ b/gcc/config/aarch64/aarch64.h @@ -222,6 +222,7 @@ enum class aarch64_feature : unsigned char { #define AARCH64_ISA_MOPS (aarch64_isa_flags & AARCH64_FL_MOPS) #define AARCH64_ISA_LS64 (aarch64_isa_flags & AARCH64_FL_LS64) #define AARCH64_ISA_CSSC (aarch64_isa_flags & AARCH64_FL_CSSC) +#define AARCH64_ISA_RCPC (aarch64_isa_flags & AARCH64_FL_RCPC) /* Crypto is an optional extension to AdvSIMD. */ #define TARGET_CRYPTO (AARCH64_ISA_CRYPTO) @@ -332,6 +333,9 @@ enum class aarch64_feature : unsigned char { /* SB instruction is enabled through +sb. */ #define TARGET_SB (AARCH64_ISA_SB) +/* RCPC loads from Armv8.3-a. */ +#define TARGET_RCPC (AARCH64_ISA_RCPC) + /* Apply the workaround for Cortex-A53 erratum 835769. */ #define TARGET_FIX_ERR_A53_835769 \ ((aarch64_fix_a53_err835769 == 2) \ diff --git a/gcc/config/aarch64/atomics.md b/gcc/config/aarch64/atomics.md index bc95f6d..dc5f52e 100644 --- a/gcc/config/aarch64/atomics.md +++ b/gcc/config/aarch64/atomics.md @@ -657,7 +657,38 @@ } ) -(define_insn "atomic_load" +(define_expand "atomic_load" + [(match_operand:ALLI 0 "register_operand" "=r") + (match_operand:ALLI 1 "aarch64_sync_memory_operand" "Q") + (match_operand:SI 2 "const_int_operand")] + "" + { + /* If TARGET_RCPC and this is an ACQUIRE load, then expand to a pattern + using UNSPECV_LDAP. */ + enum memmodel model = memmodel_from_int (INTVAL (operands[2])); + if (TARGET_RCPC + && (is_mm_acquire (model) + || is_mm_acq_rel (model))) + emit_insn (gen_aarch64_atomic_load_rcpc (operands[0], operands[1], + operands[2])); + else + emit_insn (gen_aarch64_atomic_load (operands[0], operands[1], + operands[2])); + DONE; + } +) + +(define_insn "aarch64_atomic_load_rcpc" + [(set (match_operand:ALLI 0 "register_operand" "=r") + (unspec_volatile:ALLI + [(match_operand:ALLI 1 "aarch64_sync_memory_operand" "Q") + (match_operand:SI 2 "const_int_operand")] ;; model + UNSPECV_LDAP))] + "TARGET_RCPC" + "ldapr\t%0, %1" +) + +(define_insn "aarch64_atomic_load" [(set (match_operand:ALLI 0 "register_operand" "=r") (unspec_volatile:ALLI [(match_operand:ALLI 1 "aarch64_sync_memory_operand" "Q") diff --git a/gcc/config/aarch64/iterators.md b/gcc/config/aarch64/iterators.md index 718b4c0..7c7fcbb 100644 --- a/gcc/config/aarch64/iterators.md +++ b/gcc/config/aarch64/iterators.md @@ -988,6 +988,7 @@ UNSPECV_LX ; Represent a load-exclusive. UNSPECV_SX ; Represent a store-exclusive. UNSPECV_LDA ; Represent an atomic load or load-acquire. + UNSPECV_LDAP ; Represent an atomic acquire load with RCpc semantics. UNSPECV_STL ; Represent an atomic store or store-release. UNSPECV_ATOMIC_CMPSW ; Represent an atomic compare swap. UNSPECV_ATOMIC_EXCHG ; Represent an atomic exchange. diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 55e8a14..9d73394 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -20147,9 +20147,9 @@ Enable FP16 fmla extension. This also enables FP16 extensions and floating-point instructions. This option is enabled by default for @option{-march=armv8.4-a}. Use of this option with architectures prior to Armv8.2-A is not supported. @item rcpc -Enable the RcPc extension. This does not change code generation from GCC, -but is passed on to the assembler, enabling inline asm statements to use -instructions from the RcPc extension. +Enable the RCpc extension. This enables the use of the LDAPR instructions for +load-acquire atomic semantics, and passes it on to the assembler, enabling +inline asm statements to use instructions from the RCpc extension. @item dotprod Enable the Dot Product extension. This also enables Advanced SIMD instructions. @item aes diff --git a/gcc/testsuite/gcc.target/aarch64/ldapr.c b/gcc/testsuite/gcc.target/aarch64/ldapr.c new file mode 100644 index 0000000..21f6464 --- /dev/null +++ b/gcc/testsuite/gcc.target/aarch64/ldapr.c @@ -0,0 +1,34 @@ +/* { dg-do compile } */ +/* { dg-options "-O1 -std=c99" } */ +#include + +#pragma GCC target "+rcpc" +atomic_ullong u64; +atomic_llong s64; +atomic_uint u32; +atomic_int s32; +atomic_ushort u16; +atomic_short s16; +atomic_uchar u8; +atomic_schar s8; + +#define TEST(size, rettype) \ +rettype \ +test_##size (void) \ +{ \ + return atomic_load_explicit (&size, memory_order_acquire); \ +} \ + +TEST(u64, unsigned long long) +TEST(s64, long long) +TEST(u32, unsigned int) +TEST(s32, int) +TEST(u16, unsigned short) +TEST(s16, short) +TEST(u8, unsigned char) +TEST(s8, signed char) + +/* { dg-final { scan-assembler-times "ldapr\tx" 2 } } */ +/* { dg-final { scan-assembler-times "ldapr\tw" 2 } } */ +/* { dg-final { scan-assembler-times "ldaprh\tw" 2 } } */ +/* { dg-final { scan-assembler-times "ldaprb\tw" 2 } } */ -- 2.7.4