> Am 16.06.2023 um 16:34 schrieb Jakub Jelinek <ja...@redhat.com>:
>
> Hi!
>
> While the design of these builtins in clang is questionable,
> rather than being say
> unsigned __builtin_addc (unsigned, unsigned, bool, bool *)
> so that it is clear they add two [0, 0xffffffff] range numbers
> plus one [0, 1] range carry in and give [0, 0xffffffff] range
> return plus [0, 1] range carry out, they actually instead
> add 3 [0, 0xffffffff] values together but the carry out
> isn't then the expected [0, 2] value because
> 0xffffffffULL + 0xffffffff + 0xffffffff is 0x2fffffffd,
> but just [0, 1] whether there was any overflow at all.
>
> It is something used in the wild and shorter to write than the
> corresponding
> #define __builtin_addc(a,b,carry_in,carry_out) \
> ({ unsigned _s; \
> unsigned _c1 = __builtin_uadd_overflow (a, b, &_s); \
> unsigned _c2 = __builtin_uadd_overflow (_s, carry_in, &_s); \
> *(carry_out) = (_c1 | _c2); \
> _s; })
> and so a canned builtin for something people could often use.
> It isn't that hard to maintain on the GCC side, as we just lower
> it to two .ADD_OVERFLOW calls early, and the already committed
> pottern recognization code can then make .UADDC/.USUBC calls out of
> that if the carry in is in [0, 1] range and the corresponding
> optab is supported by the target.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok
Richard
> 2023-06-16 Jakub Jelinek <ja...@redhat.com>
>
> PR middle-end/79173
> * builtin-types.def (BT_FN_UINT_UINT_UINT_UINT_UINTPTR,
> BT_FN_ULONG_ULONG_ULONG_ULONG_ULONGPTR,
> BT_FN_ULONGLONG_ULONGLONG_ULONGLONG_ULONGLONG_ULONGLONGPTR): New
> types.
> * builtins.def (BUILT_IN_ADDC, BUILT_IN_ADDCL, BUILT_IN_ADDCLL,
> BUILT_IN_SUBC, BUILT_IN_SUBCL, BUILT_IN_SUBCLL): New builtins.
> * builtins.cc (fold_builtin_addc_subc): New function.
> (fold_builtin_varargs): Handle BUILT_IN_{ADD,SUB}C{,L,LL}.
> * doc/extend.texi (__builtin_addc, __builtin_subc): Document.
>
> * gcc.target/i386/pr79173-11.c: New test.
> * gcc.dg/builtin-addc-1.c: New test.
>
> --- gcc/builtin-types.def.jj 2023-06-16 12:01:09.622759288 +0200
> +++ gcc/builtin-types.def 2023-06-16 12:04:20.277086893 +0200
> @@ -842,10 +842,17 @@ DEF_FUNCTION_TYPE_4 (BT_FN_PTR_PTR_INT_S
> BT_PTR, BT_PTR, BT_INT, BT_SIZE, BT_SIZE)
> DEF_FUNCTION_TYPE_4 (BT_FN_UINT_UINT_UINT_UINT_UINT,
> BT_UINT, BT_UINT, BT_UINT, BT_UINT, BT_UINT)
> +DEF_FUNCTION_TYPE_4 (BT_FN_UINT_UINT_UINT_UINT_UINTPTR,
> + BT_UINT, BT_UINT, BT_UINT, BT_UINT, BT_PTR_UINT)
> DEF_FUNCTION_TYPE_4 (BT_FN_UINT_FLOAT_FLOAT_FLOAT_FLOAT,
> BT_UINT, BT_FLOAT, BT_FLOAT, BT_FLOAT, BT_FLOAT)
> DEF_FUNCTION_TYPE_4 (BT_FN_ULONG_ULONG_ULONG_UINT_UINT,
> BT_ULONG, BT_ULONG, BT_ULONG, BT_UINT, BT_UINT)
> +DEF_FUNCTION_TYPE_4 (BT_FN_ULONG_ULONG_ULONG_ULONG_ULONGPTR,
> + BT_ULONG, BT_ULONG, BT_ULONG, BT_ULONG, BT_PTR_ULONG)
> +DEF_FUNCTION_TYPE_4
> (BT_FN_ULONGLONG_ULONGLONG_ULONGLONG_ULONGLONG_ULONGLONGPTR,
> + BT_ULONGLONG, BT_ULONGLONG, BT_ULONGLONG, BT_ULONGLONG,
> + BT_PTR_ULONGLONG)
> DEF_FUNCTION_TYPE_4 (BT_FN_STRING_STRING_CONST_STRING_SIZE_SIZE,
> BT_STRING, BT_STRING, BT_CONST_STRING, BT_SIZE, BT_SIZE)
> DEF_FUNCTION_TYPE_4 (BT_FN_INT_FILEPTR_INT_CONST_STRING_VALIST_ARG,
> --- gcc/builtins.def.jj 2023-06-16 12:01:09.622759288 +0200
> +++ gcc/builtins.def 2023-06-16 12:04:20.278086879 +0200
> @@ -934,6 +934,12 @@ DEF_GCC_BUILTIN (BUILT_IN_USUBLL_
> DEF_GCC_BUILTIN (BUILT_IN_UMUL_OVERFLOW, "umul_overflow",
> BT_FN_BOOL_UINT_UINT_UINTPTR, ATTR_NOTHROW_NONNULL_LEAF_LIST)
> DEF_GCC_BUILTIN (BUILT_IN_UMULL_OVERFLOW, "umull_overflow",
> BT_FN_BOOL_ULONG_ULONG_ULONGPTR, ATTR_NOTHROW_NONNULL_LEAF_LIST)
> DEF_GCC_BUILTIN (BUILT_IN_UMULLL_OVERFLOW, "umulll_overflow",
> BT_FN_BOOL_ULONGLONG_ULONGLONG_ULONGLONGPTR, ATTR_NOTHROW_NONNULL_LEAF_LIST)
> +DEF_GCC_BUILTIN (BUILT_IN_ADDC, "addc",
> BT_FN_UINT_UINT_UINT_UINT_UINTPTR, ATTR_NOTHROW_NONNULL_LEAF_LIST)
> +DEF_GCC_BUILTIN (BUILT_IN_ADDCL, "addcl",
> BT_FN_ULONG_ULONG_ULONG_ULONG_ULONGPTR, ATTR_NOTHROW_NONNULL_LEAF_LIST)
> +DEF_GCC_BUILTIN (BUILT_IN_ADDCLL, "addcll",
> BT_FN_ULONGLONG_ULONGLONG_ULONGLONG_ULONGLONG_ULONGLONGPTR,
> ATTR_NOTHROW_NONNULL_LEAF_LIST)
> +DEF_GCC_BUILTIN (BUILT_IN_SUBC, "subc",
> BT_FN_UINT_UINT_UINT_UINT_UINTPTR, ATTR_NOTHROW_NONNULL_LEAF_LIST)
> +DEF_GCC_BUILTIN (BUILT_IN_SUBCL, "subcl",
> BT_FN_ULONG_ULONG_ULONG_ULONG_ULONGPTR, ATTR_NOTHROW_NONNULL_LEAF_LIST)
> +DEF_GCC_BUILTIN (BUILT_IN_SUBCLL, "subcll",
> BT_FN_ULONGLONG_ULONGLONG_ULONGLONG_ULONGLONG_ULONGLONGPTR,
> ATTR_NOTHROW_NONNULL_LEAF_LIST)
>
> /* Category: miscellaneous builtins. */
> DEF_LIB_BUILTIN (BUILT_IN_ABORT, "abort", BT_FN_VOID,
> ATTR_TMPURE_NORETURN_NOTHROW_LEAF_COLD_LIST)
> --- gcc/builtins.cc.jj 2023-06-13 18:23:37.141794072 +0200
> +++ gcc/builtins.cc 2023-06-16 13:11:25.094406298 +0200
> @@ -9555,6 +9555,51 @@ fold_builtin_arith_overflow (location_t
> return build2_loc (loc, COMPOUND_EXPR, boolean_type_node, store, ovfres);
> }
>
> +/* Fold __builtin_{add,sub}c{,l,ll} into pair of internal functions
> + that return both result of arithmetics and overflowed boolean
> + flag in a complex integer result. */
> +
> +static tree
> +fold_builtin_addc_subc (location_t loc, enum built_in_function fcode,
> + tree *args)
> +{
> + enum internal_fn ifn;
> +
> + switch (fcode)
> + {
> + case BUILT_IN_ADDC:
> + case BUILT_IN_ADDCL:
> + case BUILT_IN_ADDCLL:
> + ifn = IFN_ADD_OVERFLOW;
> + break;
> + case BUILT_IN_SUBC:
> + case BUILT_IN_SUBCL:
> + case BUILT_IN_SUBCLL:
> + ifn = IFN_SUB_OVERFLOW;
> + break;
> + default:
> + gcc_unreachable ();
> + }
> +
> + tree type = TREE_TYPE (args[0]);
> + tree ctype = build_complex_type (type);
> + tree call = build_call_expr_internal_loc (loc, ifn, ctype, 2,
> + args[0], args[1]);
> + tree tgt = save_expr (call);
> + tree intres = build1_loc (loc, REALPART_EXPR, type, tgt);
> + tree ovfres = build1_loc (loc, IMAGPART_EXPR, type, tgt);
> + call = build_call_expr_internal_loc (loc, ifn, ctype, 2,
> + intres, args[2]);
> + tgt = save_expr (call);
> + intres = build1_loc (loc, REALPART_EXPR, type, tgt);
> + tree ovfres2 = build1_loc (loc, IMAGPART_EXPR, type, tgt);
> + ovfres = build2_loc (loc, BIT_IOR_EXPR, type, ovfres, ovfres2);
> + tree mem_arg3 = build_fold_indirect_ref_loc (loc, args[3]);
> + tree store
> + = fold_build2_loc (loc, MODIFY_EXPR, void_type_node, mem_arg3, ovfres);
> + return build2_loc (loc, COMPOUND_EXPR, type, store, intres);
> +}
> +
> /* Fold a call to __builtin_FILE to a constant string. */
>
> static inline tree
> @@ -10843,6 +10888,14 @@ fold_builtin_varargs (location_t loc, tr
> ret = fold_builtin_fpclassify (loc, args, nargs);
> break;
>
> + case BUILT_IN_ADDC:
> + case BUILT_IN_ADDCL:
> + case BUILT_IN_ADDCLL:
> + case BUILT_IN_SUBC:
> + case BUILT_IN_SUBCL:
> + case BUILT_IN_SUBCLL:
> + return fold_builtin_addc_subc (loc, fcode, args);
> +
> default:
> break;
> }
> --- gcc/doc/extend.texi.jj 2023-06-16 12:01:15.015683954 +0200
> +++ gcc/doc/extend.texi 2023-06-16 12:40:10.179841300 +0200
> @@ -12839,6 +12839,50 @@ after addition, conditional jump on carr
>
> @enddefbuiltin
>
> +@defbuiltin{unsigned int __builtin_addc (unsigned int a, unsigned int b,
> unsigned int carry_in, unsigned int *carry_out)}
> +@defbuiltinx{unsigned long int __builtin_addcl (unsigned long int a,
> unsigned long int b, unsigned int carry_in, unsigned long int *carry_out)}
> +@defbuiltinx{unsigned long long int __builtin_addcll (unsigned long long int
> a, unsigned long long int b, unsigned long long int carry_in, unsigned long
> long int *carry_out)}
> +
> +These built-in functions are equivalent to:
> +@smallexample
> + (@{ __typeof__ (@var{a}) s; \
> + __typeof__ (@var{a}) c1 = __builtin_add_overflow (@var{a}, @var{b},
> &s); \
> + __typeof__ (@var{a}) c2 = __builtin_add_overflow (s, @var{carry_in},
> &s); \
> + *(@var{carry_out}) = c1 | c2; \
> + s; @})
> +@end smallexample
> +
> +i.e.@: they add 3 unsigned values, set what the last argument
> +points to to 1 if any of the two additions overflowed (otherwise 0)
> +and return the sum of those 3 unsigned values. Note, while all
> +the first 3 arguments can have arbitrary values, better code will be
> +emitted if one of them (preferrably the third one) has only values
> +0 or 1 (i.e.@: carry-in).
> +
> +@enddefbuiltin
> +
> +@defbuiltin{unsigned int __builtin_subc (unsigned int a, unsigned int b,
> unsigned int carry_in, unsigned int *carry_out)}
> +@defbuiltinx{unsigned long int __builtin_subcl (unsigned long int a,
> unsigned long int b, unsigned int carry_in, unsigned long int *carry_out)}
> +@defbuiltinx{unsigned long long int __builtin_subcll (unsigned long long int
> a, unsigned long long int b, unsigned long long int carry_in, unsigned long
> long int *carry_out)}
> +
> +These built-in functions are equivalent to:
> +@smallexample
> + (@{ __typeof__ (@var{a}) s; \
> + __typeof__ (@var{a}) c1 = __builtin_sub_overflow (@var{a}, @var{b},
> &s); \
> + __typeof__ (@var{a}) c2 = __builtin_sub_overflow (s, @var{carry_in},
> &s); \
> + *(@var{carry_out}) = c1 | c2; \
> + s; @})
> +@end smallexample
> +
> +i.e.@: they subtract 2 unsigned values from the first unsigned value,
> +set what the last argument points to to 1 if any of the two subtractions
> +overflowed (otherwise 0) and return the result of the subtractions.
> +Note, while all the first 3 arguments can have arbitrary values, better code
> +will be emitted if one of them (preferrably the third one) has only values
> +0 or 1 (i.e.@: carry-in).
> +
> +@enddefbuiltin
> +
> @node x86 specific memory model extensions for transactional memory
> @section x86-Specific Memory Model Extensions for Transactional Memory
>
> --- gcc/testsuite/gcc.target/i386/pr79173-11.c.jj 2023-06-16
> 12:46:12.659735680 +0200
> +++ gcc/testsuite/gcc.target/i386/pr79173-11.c 2023-06-16
> 12:46:41.864323951 +0200
> @@ -0,0 +1,39 @@
> +/* PR middle-end/79173 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fno-stack-protector -masm=att" } */
> +/* { dg-final { scan-assembler-times "addq\t%r\[^\n\r]*, \\\(%rdi\\\)" 1 {
> target lp64 } } } */
> +/* { dg-final { scan-assembler-times "adcq\t%r\[^\n\r]*, 8\\\(%rdi\\\)" 1 {
> target lp64 } } } */
> +/* { dg-final { scan-assembler-times "adcq\t%r\[^\n\r]*, 16\\\(%rdi\\\)" 1 {
> target lp64 } } } */
> +/* { dg-final { scan-assembler-times "adcq\t%r\[^\n\r]*, 24\\\(%rdi\\\)" 1 {
> target lp64 } } } */
> +/* { dg-final { scan-assembler-times "subq\t%r\[^\n\r]*, \\\(%rdi\\\)" 1 {
> target lp64 } } } */
> +/* { dg-final { scan-assembler-times "sbbq\t%r\[^\n\r]*, 8\\\(%rdi\\\)" 1 {
> target lp64 } } } */
> +/* { dg-final { scan-assembler-times "sbbq\t%r\[^\n\r]*, 16\\\(%rdi\\\)" 1 {
> target lp64 } } } */
> +/* { dg-final { scan-assembler-times "sbbq\t%r\[^\n\r]*, 24\\\(%rdi\\\)" 1 {
> target lp64 } } } */
> +/* { dg-final { scan-assembler-times "addl\t%e\[^\n\r]*,
> \\\(%e\[^\n\r]*\\\)" 1 { target ia32 } } } */
> +/* { dg-final { scan-assembler-times "adcl\t%e\[^\n\r]*,
> 4\\\(%e\[^\n\r]*\\\)" 1 { target ia32 } } } */
> +/* { dg-final { scan-assembler-times "adcl\t%e\[^\n\r]*,
> 8\\\(%e\[^\n\r]*\\\)" 1 { target ia32 } } } */
> +/* { dg-final { scan-assembler-times "adcl\t%e\[^\n\r]*,
> 12\\\(%e\[^\n\r]*\\\)" 1 { target ia32 } } } */
> +/* { dg-final { scan-assembler-times "subl\t%e\[^\n\r]*,
> \\\(%e\[^\n\r]*\\\)" 1 { target ia32 } } } */
> +/* { dg-final { scan-assembler-times "sbbl\t%e\[^\n\r]*,
> 4\\\(%e\[^\n\r]*\\\)" 1 { target ia32 } } } */
> +/* { dg-final { scan-assembler-times "sbbl\t%e\[^\n\r]*,
> 8\\\(%e\[^\n\r]*\\\)" 1 { target ia32 } } } */
> +/* { dg-final { scan-assembler-times "sbbl\t%e\[^\n\r]*,
> 12\\\(%e\[^\n\r]*\\\)" 1 { target ia32 } } } */
> +
> +void
> +foo (unsigned long *p, unsigned long *q)
> +{
> + unsigned long c;
> + p[0] = __builtin_addcl (p[0], q[0], 0, &c);
> + p[1] = __builtin_addcl (p[1], q[1], c, &c);
> + p[2] = __builtin_addcl (p[2], q[2], c, &c);
> + p[3] = __builtin_addcl (p[3], q[3], c, &c);
> +}
> +
> +void
> +bar (unsigned long *p, unsigned long *q)
> +{
> + unsigned long c;
> + p[0] = __builtin_subcl (p[0], q[0], 0, &c);
> + p[1] = __builtin_subcl (p[1], q[1], c, &c);
> + p[2] = __builtin_subcl (p[2], q[2], c, &c);
> + p[3] = __builtin_subcl (p[3], q[3], c, &c);
> +}
> --- gcc/testsuite/gcc.dg/builtin-addc-1.c.jj 2023-06-16 12:47:57.247261195
> +0200
> +++ gcc/testsuite/gcc.dg/builtin-addc-1.c 2023-06-16 13:03:19.269260147
> +0200
> @@ -0,0 +1,101 @@
> +/* { dg-do run } */
> +/* { dg-options "-O2 -g" } */
> +
> +int
> +main ()
> +{
> + unsigned int c;
> + unsigned long cl;
> + unsigned long long cll;
> + if (__builtin_addc (1, 42, 0, &c) != 43 || c != 0)
> + __builtin_abort ();
> + if (__builtin_addc (1, 42, 15, &c) != 58 || c != 0)
> + __builtin_abort ();
> + if (__builtin_addc (-2U, -3U, -4U, &c) != -9U || c != 1)
> + __builtin_abort ();
> + if (__builtin_addc (-2U, 1, 0, &c) != -1U || c != 0)
> + __builtin_abort ();
> + if (__builtin_addc (-2U, 1, 1, &c) != 0 || c != 1)
> + __builtin_abort ();
> + if (__builtin_addc (-2U, 2, 0, &c) != 0 || c != 1)
> + __builtin_abort ();
> + if (__builtin_addc (-2U, 0, 2, &c) != 0 || c != 1)
> + __builtin_abort ();
> + if (__builtin_addcl (1L, 42L, 0L, &cl) != 43 || cl != 0L)
> + __builtin_abort ();
> + if (__builtin_addcl (1L, 42L, 15L, &cl) != 58 || cl != 0L)
> + __builtin_abort ();
> + if (__builtin_addcl (-2UL, -3UL, -4UL, &cl) != -9UL || cl != 1L)
> + __builtin_abort ();
> + if (__builtin_addcl (-2UL, 1L, 0L, &cl) != -1UL || cl != 0L)
> + __builtin_abort ();
> + if (__builtin_addcl (-2UL, 1L, 1L, &cl) != 0 || cl != 1L)
> + __builtin_abort ();
> + if (__builtin_addcl (-2UL, 2L, 0L, &cl) != 0 || cl != 1L)
> + __builtin_abort ();
> + if (__builtin_addcl (-2UL, 0L, 2L, &cl) != 0 || cl != 1L)
> + __builtin_abort ();
> + if (__builtin_addcll (1LL, 42LL, 0LL, &cll) != 43 || cll != 0LL)
> + __builtin_abort ();
> + if (__builtin_addcll (1LL, 42LL, 15LL, &cll) != 58 || cll != 0LL)
> + __builtin_abort ();
> + if (__builtin_addcll (-2ULL, -3ULL, -4ULL, &cll) != -9ULL || cll != 1LL)
> + __builtin_abort ();
> + if (__builtin_addcll (-2ULL, 1LL, 0LL, &cll) != -1ULL || cll != 0LL)
> + __builtin_abort ();
> + if (__builtin_addcll (-2ULL, 1LL, 1LL, &cll) != 0 || cll != 1LL)
> + __builtin_abort ();
> + if (__builtin_addcll (-2ULL, 2LL, 0LL, &cll) != 0 || cll != 1LL)
> + __builtin_abort ();
> + if (__builtin_addcll (-2ULL, 0LL, 2LL, &cll) != 0 || cll != 1LL)
> + __builtin_abort ();
> + if (__builtin_subc (42, 42, 0, &c) != 0 || c != 0)
> + __builtin_abort ();
> + if (__builtin_subc (42, 42, 1, &c) != -1U || c != 1)
> + __builtin_abort ();
> + if (__builtin_subc (1, -3U, -4U, &c) != 8 || c != 1)
> + __builtin_abort ();
> + if (__builtin_subc (-2U, 1, 0, &c) != -3U || c != 0)
> + __builtin_abort ();
> + if (__builtin_subc (-2U, -1U, 0, &c) != -1U || c != 1)
> + __builtin_abort ();
> + if (__builtin_subc (-2U, -2U, 0, &c) != 0 || c != 0)
> + __builtin_abort ();
> + if (__builtin_subc (-2U, -2U, 1, &c) != -1U || c != 1)
> + __builtin_abort ();
> + if (__builtin_subc (-2U, 1, -2U, &c) != -1U || c != 1)
> + __builtin_abort ();
> + if (__builtin_subcl (42L, 42L, 0L, &cl) != 0L || cl != 0L)
> + __builtin_abort ();
> + if (__builtin_subcl (42L, 42L, 1L, &cl) != -1UL || cl != 1L)
> + __builtin_abort ();
> + if (__builtin_subcl (1L, -3UL, -4UL, &cl) != 8L || cl != 1L)
> + __builtin_abort ();
> + if (__builtin_subcl (-2UL, 1L, 0L, &cl) != -3UL || cl != 0L)
> + __builtin_abort ();
> + if (__builtin_subcl (-2UL, -1UL, 0L, &cl) != -1UL || cl != 1L)
> + __builtin_abort ();
> + if (__builtin_subcl (-2UL, -2UL, 0L, &cl) != 0L || cl != 0L)
> + __builtin_abort ();
> + if (__builtin_subcl (-2UL, -2UL, 1L, &cl) != -1UL || cl != 1L)
> + __builtin_abort ();
> + if (__builtin_subcl (-2UL, 1L, -2UL, &cl) != -1UL || cl != 1L)
> + __builtin_abort ();
> + if (__builtin_subcll (42LL, 42LL, 0LL, &cll) != 0LL || cll != 0LL)
> + __builtin_abort ();
> + if (__builtin_subcll (42LL, 42LL, 1LL, &cll) != -1ULL || cll != 1LL)
> + __builtin_abort ();
> + if (__builtin_subcll (1LL, -3ULL, -4ULL, &cll) != 8LL || cll != 1LL)
> + __builtin_abort ();
> + if (__builtin_subcll (-2ULL, 1LL, 0LL, &cll) != -3ULL || cll != 0LL)
> + __builtin_abort ();
> + if (__builtin_subcll (-2ULL, -1ULL, 0LL, &cll) != -1ULL || cll != 1LL)
> + __builtin_abort ();
> + if (__builtin_subcll (-2ULL, -2ULL, 0LL, &cll) != 0LL || cll != 0LL)
> + __builtin_abort ();
> + if (__builtin_subcll (-2ULL, -2ULL, 1LL, &cll) != -1ULL || cll != 1LL)
> + __builtin_abort ();
> + if (__builtin_subcll (-2ULL, 1LL, -2ULL, &cll) != -1ULL || cll != 1LL)
> + __builtin_abort ();
> + return 0;
> +}
>
> Jakub
>
Re: [PATCH] builtins: Add support for clang compatible __builtin_{add, sub}c{, l, ll} [PR79173]
Richard Biener via Gcc-patches Fri, 16 Jun 2023 10:06:54 -0700
- [PATCH] builtins: Add support for clang com... Jakub Jelinek via Gcc-patches
- Re: [PATCH] builtins: Add support for ... Richard Biener via Gcc-patches
