https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111309
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:7383cb56e1170789929201b0dadc156888928fdd commit r14-5435-g7383cb56e1170789929201b0dadc156888928fdd Author: Jakub Jelinek <ja...@redhat.com> Date: Tue Nov 14 10:38:56 2023 +0100 Add type-generic clz/ctz/clrsb/ffs/parity/popcount builtins [PR111309] The following patch adds 6 new type-generic builtins, __builtin_clzg __builtin_ctzg __builtin_clrsbg __builtin_ffsg __builtin_parityg __builtin_popcountg The g at the end stands for generic because the unsuffixed variant of the builtins already have unsigned int or int arguments. The main reason to add these is to support arbitrary unsigned (for clrsb/ffs signed) bit-precise integer types and also __int128 which wasn't supported by the existing builtins, so that e.g. <stdbit.h> type-generic functions could then support not just bit-precise unsigned integer type whose width matches a standard or extended integer type, but others too. None of these new builtins promote their first argument, so the argument can be e.g. unsigned char or unsigned short or unsigned __int20 etc. The first 2 support either 1 or 2 arguments, if only 1 argument is supplied, the behavior is undefined for argument 0 like for other __builtin_c[lt]z* builtins, if 2 arguments are supplied, the second argument should be int that will be returned if the argument is 0. All other builtins have just one argument. For __builtin_clrsbg and __builtin_ffsg the argument shall be any signed standard/extended or bit-precise integer, for the others any unsigned standard/extended or bit-precise integer (bool not allowed). One possibility would be to also allow signed integer types for the clz/ctz/parity/popcount ones (and just cast the argument to unsigned_type_for during folding) and similarly unsigned integer types for the clrsb/ffs ones, dunno what is better; for stdbit.h the current version is sufficient and diagnoses use of the inappropriate sign, though on the other side I wonder if users won't be confused by __builtin_clzg (1) being an error and having to write __builtin_clzg (1U). The new builtins are lowered to corresponding builtins with other suffixes or internal calls (plus casts and adjustments where needed) during FE folding or during gimplification at latest, the non-suffixed builtins handling precisions up to precision of int, l up to precision of long, ll up to precision of long long, up to __int128 precision lowered to double-word expansion early and the rest (which must be _BitInt) lowered to internal fn calls - those are then lowered during bitint lowering pass. The patch also changes representation of IFN_CLZ and IFN_CTZ calls, previously they were in the IL only if they are directly supported optab and depending on C[LT]Z_DEFINED_VALUE_AT_ZERO (...) == 2 they had or didn't have defined behavior at 0, now they are in the IL either if directly supported optab, or for the large/huge BITINT_TYPEs and they have either 1 or 2 arguments. If one, the behavior is undefined at zero, if 2, the second argument is an int constant that should be returned for 0. As there is no extra support during expansion, for directly supported optab the second argument if present should still match the C[LT]Z_DEFINED_VALUE_AT_ZERO (...) == 2 value, but for BITINT_TYPE arguments it can be arbitrary int INTEGER_CST. The indended uses in stdbit.h are e.g. #ifdef __has_builtin #if __has_builtin(__builtin_clzg) && __has_builtin(__builtin_ctzg) && __has_builtin(__builtin_popcountg) #define stdc_leading_zeros(value) \ ((unsigned int) __builtin_clzg (value, __builtin_popcountg ((__typeof (value)) ~(__typeof (value)) 0))) #define stdc_leading_ones(value) \ ((unsigned int) __builtin_clzg ((__typeof (value)) ~(value), __builtin_popcountg ((__typeof (value)) ~(__typeof (value)) 0))) #define stdc_first_trailing_one(value) \ ((unsigned int) (__builtin_ctzg (value, -1) + 1)) #define stdc_trailing_zeros(value) \ ((unsigned int) __builtin_ctzg (value, __builtin_popcountg ((__typeof (value)) ~(__typeof (value)) 0))) #endif #endif where __builtin_popcountg ((__typeof (x)) -1) computes the bit precision of x's type (kind of _Bitwidthof (x) alternative). They also allow casting of arbitrary unsigned _BitInt other than unsigned _BitInt(1) to corresponding signed _BitInt by using signed _BitInt(__builtin_popcountg ((__typeof (a)) -1)) and of arbitrary signed _BitInt to corresponding unsigned _BitInt using unsigned _BitInt(__builtin_clrsbg ((__typeof (a)) -1) + 1). 2023-11-14 Jakub Jelinek <ja...@redhat.com> PR c/111309 gcc/ * builtins.def (BUILT_IN_CLZG, BUILT_IN_CTZG, BUILT_IN_CLRSBG, BUILT_IN_FFSG, BUILT_IN_PARITYG, BUILT_IN_POPCOUNTG): New builtins. * builtins.cc (fold_builtin_bit_query): New function. (fold_builtin_1): Use it for BUILT_IN_{CLZ,CTZ,CLRSB,FFS,PARITY,POPCOUNT}G. (fold_builtin_2): Use it for BUILT_IN_{CLZ,CTZ}G. * fold-const-call.cc: Fix comment typo on tm.h inclusion. (fold_const_call_ss): Handle CFN_BUILT_IN_{CLZ,CTZ,CLRSB,FFS,PARITY,POPCOUNT}G. (fold_const_call_sss): New function. (fold_const_call_1): Call it for 2 argument functions returning scalar when passed 2 INTEGER_CSTs. * genmatch.cc (cmp_operand): For function calls also compare number of arguments. (fns_cmp): New function. (dt_node::gen_kids): Sort fns and generic_fns. (dt_node::gen_kids_1): Handle fns with the same id but different number of arguments. * match.pd (CLZ simplifications): Drop checks for defined behavior at zero. Add variant of simplifications for IFN_CLZ with 2 arguments. (CTZ simplifications): Drop checks for defined behavior at zero, don't optimize precisions above MAX_FIXED_MODE_SIZE. Add variant of simplifications for IFN_CTZ with 2 arguments. (a != 0 ? CLZ(a) : CST -> .CLZ(a)): Use TREE_TYPE (@3) instead of type, add BITINT_TYPE handling, create 2 argument IFN_CLZ rather than one argument. Add variant for matching CLZ with 2 arguments. (a != 0 ? CTZ(a) : CST -> .CTZ(a)): Similarly. * gimple-lower-bitint.cc (bitint_large_huge::lower_bit_query): New method. (bitint_large_huge::lower_call): Use it for IFN_{CLZ,CTZ,CLRSB,FFS} and IFN_{PARITY,POPCOUNT} calls. * gimple-range-op.cc (cfn_clz::fold_range): Don't check CLZ_DEFINED_VALUE_AT_ZERO for m_gimple_call_internal_p, instead assume defined value at zero if the call has 2 arguments and use second argument value for that case. (cfn_ctz::fold_range): Similarly. (gimple_range_op_handler::maybe_builtin_call): Use op_cfn_clz_internal or op_cfn_ctz_internal only if internal fn call has 2 arguments and set m_op2 in that case. * tree-vect-patterns.cc (vect_recog_ctz_ffs_pattern, vect_recog_popcount_clz_ctz_ffs_pattern): For value defined at zero use second argument of calls if present, otherwise assume UB at zero, create 2 argument .CLZ/.CTZ calls if needed. * tree-vect-stmts.cc (vectorizable_call): Handle 2 argument .CLZ/.CTZ calls. * tree-ssa-loop-niter.cc (build_cltz_expr): Create 2 argument .CLZ/.CTZ calls if needed. * tree-ssa-forwprop.cc (simplify_count_trailing_zeroes): Create 2 argument .CTZ calls if needed. * tree-ssa-phiopt.cc (cond_removal_in_builtin_zero_pattern): Handle 2 argument .CLZ/.CTZ calls, handle BITINT_TYPE, create 2 argument .CLZ/.CTZ calls. * doc/extend.texi (__builtin_clzg, __builtin_ctzg, __builtin_clrsbg, __builtin_ffsg, __builtin_parityg, __builtin_popcountg): Document. gcc/c-family/ * c-common.cc (check_builtin_function_arguments): Handle BUILT_IN_{CLZ,CTZ,CLRSB,FFS,PARITY,POPCOUNT}G. * c-gimplify.cc (c_gimplify_expr): If __builtin_c[lt]zg second argument hasn't been folded into constant yet, transform it to one argument call inside of a COND_EXPR which for first argument 0 returns the second argument. gcc/c/ * c-typeck.cc (convert_arguments): Don't promote first argument of BUILT_IN_{CLZ,CTZ,CLRSB,FFS,PARITY,POPCOUNT}G. gcc/cp/ * call.cc (magic_varargs_p): Return 4 for BUILT_IN_{CLZ,CTZ,CLRSB,FFS,PARITY,POPCOUNT}G. (build_over_call): Don't promote first argument of BUILT_IN_{CLZ,CTZ,CLRSB,FFS,PARITY,POPCOUNT}G. * cp-gimplify.cc (cp_gimplify_expr): For BUILT_IN_C{L,T}ZG use c_gimplify_expr. gcc/testsuite/ * c-c++-common/pr111309-1.c: New test. * c-c++-common/pr111309-2.c: New test. * gcc.dg/torture/bitint-43.c: New test. * gcc.dg/torture/bitint-44.c: New test.
