TARGET_HAS_FMV_TARGET_ATTRIBUTE should be a separate patch? it seems not related to TARGET_OPTION_FUNCTION_VERSIONS and TARGET_COMPARE_VERSION_PRIORITY?
On Thu, Oct 24, 2024 at 3:13 PM Yangyu Chen <c...@cyyself.name> wrote: > > This patch implements TARGET_COMPARE_VERSION_PRIORITY and > TARGET_OPTION_FUNCTION_VERSIONS for RISC-V. > > The TARGET_COMPARE_VERSION_PRIORITY is implemented to compare the > priority of two function versions based on the rules defined in the > RISC-V C-API Doc PR #85: > > https://github.com/riscv-non-isa/riscv-c-api-doc/pull/85/files#diff-79a93ca266139524b8b642e582ac20999357542001f1f4666fbb62b6fb7a5824R721 > > If multiple versions have equal priority, we select the function with > the most number of feature bits generated by > riscv_minimal_hwprobe_feature_bits. When it comes to the same number of > feature bits, we diff two versions and select the one with the least > significant bit set. Since a feature appears earlier in the feature_bits > might be more important to performance. > > The TARGET_OPTION_FUNCTION_VERSIONS is implemented to check whether the > two function versions are the same. This Implementation reuses the code > in TARGET_COMPARE_VERSION_PRIORITY and check it returns 0, which means > the equal priority. > > Co-Developed-by: Hank Chang <hank.ch...@sifive.com> > > gcc/ChangeLog: > > * config/riscv/riscv-target-attr.cc > (riscv_target_attr_parser::update_settings): never free the > arch string. > * config/riscv/riscv.cc > (parse_features_for_version): New function. > (compare_fmv_features): New function. > (riscv_compare_version_priority): New function. > (riscv_common_function_versions): New function. > (TARGET_COMPARE_VERSION_PRIORITY): Implement it. > (TARGET_OPTION_FUNCTION_VERSIONS): Implement it. > * config/riscv/riscv.h (TARGET_HAS_FMV_TARGET_ATTRIBUTE): Define > it to 0 to use "target_version" for function versioning. > --- > gcc/config/riscv/riscv-target-attr.cc | 4 - > gcc/config/riscv/riscv.cc | 127 ++++++++++++++++++++++++++ > gcc/config/riscv/riscv.h | 2 + > 3 files changed, 129 insertions(+), 4 deletions(-) > > diff --git a/gcc/config/riscv/riscv-target-attr.cc > b/gcc/config/riscv/riscv-target-attr.cc > index 087fbae77b0..4c85ad60b72 100644 > --- a/gcc/config/riscv/riscv-target-attr.cc > +++ b/gcc/config/riscv/riscv-target-attr.cc > @@ -239,10 +239,6 @@ riscv_target_attr_parser::update_settings (struct > gcc_options *opts) const > { > std::string local_arch = m_subset_list->to_string (true); > const char* local_arch_str = local_arch.c_str (); > - struct cl_target_option *default_opts > - = TREE_TARGET_OPTION (target_option_default_node); > - if (opts->x_riscv_arch_string != default_opts->x_riscv_arch_string) > - free (CONST_CAST (void *, (const void *) opts->x_riscv_arch_string)); > opts->x_riscv_arch_string = xstrdup (local_arch_str); > > riscv_set_arch_by_subset_list (m_subset_list, opts); > diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc > index 3ac40234345..947864fc3a6 100644 > --- a/gcc/config/riscv/riscv.cc > +++ b/gcc/config/riscv/riscv.cc > @@ -12574,6 +12574,127 @@ riscv_c_mode_for_floating_type (enum tree_index ti) > return default_mode_for_floating_type (ti); > } > > +/* This parses the attribute arguments to target_version in DECL and modifies > + the feature mask and priority required to select those targets. */ > +static void > +parse_features_for_version (tree decl, > + struct riscv_feature_bits &res, > + int &priority) > +{ > + tree version_attr = lookup_attribute ("target_version", > + DECL_ATTRIBUTES (decl)); > + if (version_attr == NULL_TREE) > + { > + res.length = 0; > + priority = 0; > + return; > + } > + > + const char *version_string = TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE > + (version_attr))); > + gcc_assert (version_string != NULL); > + if (strcmp (version_string, "default") == 0) > + { > + res.length = 0; > + priority = 0; > + return; > + } > + struct cl_target_option cur_target; > + cl_target_option_save (&cur_target, &global_options, > + &global_options_set); > + /* Always set to default option before parsing "arch=+..." */ > + struct cl_target_option *default_opts > + = TREE_TARGET_OPTION (target_option_default_node); > + cl_target_option_restore (&global_options, &global_options_set, > + default_opts); > + > + riscv_process_target_attr (version_string, > + DECL_SOURCE_LOCATION (decl)); > + > + priority = global_options.x_riscv_fmv_priority; > + const char *arch_string = global_options.x_riscv_arch_string; > + bool parse_res > + = riscv_minimal_hwprobe_feature_bits (arch_string, &res, > + DECL_SOURCE_LOCATION (decl)); > + gcc_assert (parse_res); > + > + if (arch_string != default_opts->x_riscv_arch_string) > + free (CONST_CAST (void *, (const void *) arch_string)); > + > + cl_target_option_restore (&global_options, &global_options_set, > + &cur_target); > +} > + > +/* Compare priorities of two feature masks. Return: > + 1: mask1 is higher priority > + -1: mask2 is higher priority > + 0: masks are equal. > + Since riscv_feature_bits has total 128 bits to be used as mask, when > counting > + the total 1s in the mask, the 1s in group1 needs to multiply a weight. */ > +static int > +compare_fmv_features (const struct riscv_feature_bits &mask1, > + const struct riscv_feature_bits &mask2, > + int prio1, int prio2) > +{ > + unsigned length1 = mask1.length, length2 = mask2.length; > + /* 1. Compare length, for length == 0 means default version, which should > be > + the lowest priority). */ > + if (length1 != length2) > + return length1 > length2 ? 1 : -1; > + /* 2. Compare the priority. */ > + if (prio1 != prio2) > + return prio1 > prio2 ? 1 : -1; > + /* 3. Compare the total number of 1s in the mask. */ > + unsigned pop1 = 0, pop2 = 0; > + for (unsigned i = 0; i < length1; i++) > + { > + pop1 += __builtin_popcountll (mask1.features[i]); > + pop2 += __builtin_popcountll (mask2.features[i]); > + } > + if (pop1 != pop2) > + return pop1 > pop2 ? 1 : -1; > + /* 4. Compare the mask bit by bit order. */ > + for (unsigned i = 0; i < length1; i++) > + { > + unsigned long long xor_mask = mask1.features[i] ^ mask2.features[i]; > + if (xor_mask == 0) > + continue; > + return TEST_BIT (mask1.features[i], __builtin_ctzll (xor_mask)) ? 1 : > -1; > + } > + /* 5. If all bits are equal, return 0. */ > + return 0; > +} > + > +/* Compare priorities of two version decls. Return: > + 1: mask1 is higher priority > + -1: mask2 is higher priority > + 0: masks are equal. */ > +int > +riscv_compare_version_priority (tree decl1, tree decl2) > +{ > + struct riscv_feature_bits mask1, mask2; > + int prio1, prio2; > + > + parse_features_for_version (decl1, mask1, prio1); > + parse_features_for_version (decl2, mask2, prio2); > + > + return compare_fmv_features (mask1, mask2, prio1, prio2); > +} > + > +/* This function returns true if FN1 and FN2 are versions of the same > function, > + that is, the target_version attributes of the function decls are > different. > + This assumes that FN1 and FN2 have the same signature. */ > + > +bool > +riscv_common_function_versions (tree fn1, tree fn2) > +{ > + if (TREE_CODE (fn1) != FUNCTION_DECL > + || TREE_CODE (fn2) != FUNCTION_DECL) > + return false; > + > + return riscv_compare_version_priority (fn1, fn2) != 0; > +} > + > /* On riscv we have an ABI defined safe buffer. This constant is used to > determining the probe offset for alloca. */ > > @@ -12948,6 +13069,12 @@ riscv_stack_clash_protection_alloca_probe_range > (void) > #undef TARGET_C_MODE_FOR_FLOATING_TYPE > #define TARGET_C_MODE_FOR_FLOATING_TYPE riscv_c_mode_for_floating_type > > +#undef TARGET_COMPARE_VERSION_PRIORITY > +#define TARGET_COMPARE_VERSION_PRIORITY riscv_compare_version_priority > + > +#undef TARGET_OPTION_FUNCTION_VERSIONS > +#define TARGET_OPTION_FUNCTION_VERSIONS riscv_common_function_versions > + > struct gcc_target targetm = TARGET_INITIALIZER; > > #include "gt-riscv.h" > diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h > index 2ff9c1024f3..8a8b08b6b51 100644 > --- a/gcc/config/riscv/riscv.h > +++ b/gcc/config/riscv/riscv.h > @@ -1303,4 +1303,6 @@ extern void riscv_remove_unneeded_save_restore_calls > (void); > the target attribute. */ > #define TARGET_CLONES_ATTR_SEPARATOR '#' > > +#define TARGET_HAS_FMV_TARGET_ATTRIBUTE 0 > + > #endif /* ! GCC_RISCV_H */ > -- > 2.45.2 >
