Hi! Re <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91985#c4>, which reports (and I hereby confirm) that these changes quoted below introduce "lto1: internal compiler error" for (at least) nvptx offloading, and such a backtrace seemed vaguely familiar, and I did remember having fixed a similar issue before, and indeed it seems to be another instance of such a problem. In particular, and assuming that I'm understanding this correctly, the following part of the changes (for brevity formatted with 'diff --ignore-space-change'):
--- gcc/tree.c
+++ gcc/tree.c
@@ -10334,6 +10334,8 @@ build_common_tree_nodes (bool signed_char)
uint64_type_node = make_or_reuse_type (64, 1);
/* Decimal float types. */
+ if (targetm.decimal_float_supported_p ())
+ {
dfloat32_type_node = make_node (REAL_TYPE);
TYPE_PRECISION (dfloat32_type_node) = DECIMAL32_TYPE_SIZE;
SET_TYPE_MODE (dfloat32_type_node, SDmode);
@@ -10351,6 +10353,7 @@ build_common_tree_nodes (bool signed_char)
SET_TYPE_MODE (dfloat128_type_node, TDmode);
layout_type (dfloat128_type_node);
dfloat128_ptr_type_node = build_pointer_type (dfloat128_type_node);
+ }
complex_integer_type_node = build_complex_type (integer_type_node, true);
complex_float_type_node = build_complex_type (float_type_node, true);
... does introduce a mismatch in the 'preload_common_nodes' between
target (for example, x86_64-pc-linux-gnu with
'targetm.decimal_float_supported_p'), and the offload target (for
example, nvptx-none without 'targetm.decimal_float_supported_p'), and
then LTO read-in explodes because the codes are then offset between
producer (target) and consumer (offload target).
For reference/context of the previous issue, see
<http://mid.mail-archive.com/87twdgb9zi.fsf@hertz.schwinge.homeip.net>,
and following messages.
If I turn that conditional cited above into 'if (1)', then nvptx
offloading testing seems to return to normality, but I have not yet
assessed whether that has any ill effects on decimal float types support,
and/or how this should be fixed properly. (Julian, please have a look,
if you can, or tell me if you're busy with other things.)
For reference:
On 2019-11-22T16:40:01+0000, Joseph Myers <jos...@codesourcery.com> wrote:
> Code that directly uses _Decimal* types on architectures not
> supporting DFP is properly diagnosed ("error: decimal floating-point
> not supported for this target"), via a call to
> targetm.decimal_float_supported_p, if the _Decimal32, _Decimal64 or
> _Decimal128 keywords are used to access it. Use via mode attributes
> is also diagnosed ("unable to emulate 'SD'"); so is use of the
> FLOAT_CONST_DECIMAL64 pragma. However, it is possible to access those
> types via typeof applied to constants or built-in functions without
> such an error. I expect that there are ways to get an ICE from this;
> certainly it uses a completely undefined ABI.
>
> This patch arranges for the types not to exist in the compiler at all
> when DFP is not supported. As is done with unsupported _FloatN /
> _FloatNx types, the global tree nodes are left as NULL_TREE, and the
> built-in function machinery is made to use error_mark_node for them in
> that case in builtin-types.def, so that the built-in functions are
> unavailable. Code handling constants is adjusted to give an error,
> and other code that might not work with the global tree nodes being
> NULL_TREE is also updated.
>
> Bootstrapped with no regressions for x86_64-pc-linux-gnu. Also tested
> with no regressions for cross to aarch64-linux-gnu, as a configuration
> without DFP support. OK to commit (the changes that aren't C front-end
> changes)?
>
> gcc:
> 2019-11-22 Joseph Myers <jos...@codesourcery.com>
>
> PR c/91985
> * builtin-types.def (BT_DFLOAT32, BT_DFLOAT64, BT_DFLOAT128)
> (BT_DFLOAT32_PTR, BT_DFLOAT64_PTR, BT_DFLOAT128_PTR): Define to
> error_mark_node if corresponding global tree node is NULL.
> * tree.c (build_common_tree_nodes): Do not initialize
> dfloat32_type_node, dfloat64_type_node or dfloat128_type_node if
> decimal floating-point not supported.
>
> gcc/c:
> 2019-11-22 Joseph Myers <jos...@codesourcery.com>
>
> PR c/91985
> * c-decl.c (finish_declspecs): Use int instead of decimal
> floating-point types if decimal floating-point not supported.
>
> gcc/c-family:
> 2019-11-22 Joseph Myers <jos...@codesourcery.com>
>
> PR c/91985
> * c-common.c (c_common_type_for_mode): Handle decimal
> floating-point types being NULL_TREE.
> * c-format.c (get_format_for_type_1): Handle specified types being
> NULL_TREE.
> * c-lex.c (interpret_float): Give an error for decimal
> floating-point constants when decimal floating-point not
> supported.
>
> gcc/lto:
> 2019-11-22 Joseph Myers <jos...@codesourcery.com>
>
> PR c/91985
> * lto-lang.c (lto_type_for_mode): Handle decimal floating-point
> types being NULL_TREE.
>
> gcc/testsuite:
> 2019-11-22 Joseph Myers <jos...@codesourcery.com>
>
> PR c/91985
> * gcc.dg/c2x-no-dfp-1.c, gcc.dg/gnu2x-builtins-no-dfp-1.c: New
> tests.
> * gcc.dg/fltconst-pedantic-dfp.c: Expect errors when decimal
> floating-point not supported.
>
> Index: gcc/builtin-types.def
> ===================================================================
> --- gcc/builtin-types.def (revision 278603)
> +++ gcc/builtin-types.def (working copy)
> @@ -136,12 +136,24 @@ DEF_PRIMITIVE_TYPE (BT_WINT, wint_type_node)
> DEF_PRIMITIVE_TYPE (BT_STRING, string_type_node)
> DEF_PRIMITIVE_TYPE (BT_CONST_STRING, const_string_type_node)
>
> -DEF_PRIMITIVE_TYPE (BT_DFLOAT32, dfloat32_type_node)
> -DEF_PRIMITIVE_TYPE (BT_DFLOAT64, dfloat64_type_node)
> -DEF_PRIMITIVE_TYPE (BT_DFLOAT128, dfloat128_type_node)
> -DEF_PRIMITIVE_TYPE (BT_DFLOAT32_PTR, dfloat32_ptr_type_node)
> -DEF_PRIMITIVE_TYPE (BT_DFLOAT64_PTR, dfloat64_ptr_type_node)
> -DEF_PRIMITIVE_TYPE (BT_DFLOAT128_PTR, dfloat128_ptr_type_node)
> +DEF_PRIMITIVE_TYPE (BT_DFLOAT32, (dfloat32_type_node
> + ? dfloat32_type_node
> + : error_mark_node))
> +DEF_PRIMITIVE_TYPE (BT_DFLOAT64, (dfloat64_type_node
> + ? dfloat64_type_node
> + : error_mark_node))
> +DEF_PRIMITIVE_TYPE (BT_DFLOAT128, (dfloat128_type_node
> + ? dfloat128_type_node
> + : error_mark_node))
> +DEF_PRIMITIVE_TYPE (BT_DFLOAT32_PTR, (dfloat32_ptr_type_node
> + ? dfloat32_ptr_type_node
> + : error_mark_node))
> +DEF_PRIMITIVE_TYPE (BT_DFLOAT64_PTR, (dfloat64_ptr_type_node
> + ? dfloat64_ptr_type_node
> + : error_mark_node))
> +DEF_PRIMITIVE_TYPE (BT_DFLOAT128_PTR, (dfloat128_ptr_type_node
> + ? dfloat128_ptr_type_node
> + : error_mark_node))
>
> DEF_PRIMITIVE_TYPE (BT_VALIST_REF, va_list_ref_type_node)
> DEF_PRIMITIVE_TYPE (BT_VALIST_ARG, va_list_arg_type_node)
> Index: gcc/c/c-decl.c
> ===================================================================
> --- gcc/c/c-decl.c (revision 278603)
> +++ gcc/c/c-decl.c (working copy)
> @@ -11619,7 +11619,9 @@ finish_declspecs (struct c_declspecs *specs)
> case cts_dfloat128:
> gcc_assert (!specs->long_p && !specs->long_long_p && !specs->short_p
> && !specs->signed_p && !specs->unsigned_p &&
> !specs->complex_p);
> - if (specs->typespec_word == cts_dfloat32)
> + if (!targetm.decimal_float_supported_p ())
> + specs->type = integer_type_node;
> + else if (specs->typespec_word == cts_dfloat32)
> specs->type = dfloat32_type_node;
> else if (specs->typespec_word == cts_dfloat64)
> specs->type = dfloat64_type_node;
> Index: gcc/c-family/c-common.c
> ===================================================================
> --- gcc/c-family/c-common.c (revision 278603)
> +++ gcc/c-family/c-common.c (working copy)
> @@ -2321,11 +2321,14 @@ c_common_type_for_mode (machine_mode mode, int uns
> return build_vector_type_for_mode (inner_type, mode);
> }
>
> - if (mode == TYPE_MODE (dfloat32_type_node))
> + if (dfloat32_type_node != NULL_TREE
> + && mode == TYPE_MODE (dfloat32_type_node))
> return dfloat32_type_node;
> - if (mode == TYPE_MODE (dfloat64_type_node))
> + if (dfloat64_type_node != NULL_TREE
> + && mode == TYPE_MODE (dfloat64_type_node))
> return dfloat64_type_node;
> - if (mode == TYPE_MODE (dfloat128_type_node))
> + if (dfloat128_type_node != NULL_TREE
> + && mode == TYPE_MODE (dfloat128_type_node))
> return dfloat128_type_node;
>
> if (ALL_SCALAR_FIXED_POINT_MODE_P (mode))
> Index: gcc/c-family/c-format.c
> ===================================================================
> --- gcc/c-family/c-format.c (revision 278603)
> +++ gcc/c-family/c-format.c (working copy)
> @@ -4390,7 +4390,7 @@ get_format_for_type_1 (const format_kind_info *fki
> for (int i = 0; i < FMT_LEN_MAX; i++)
> {
> const format_type_detail *ftd = &spec->types[i];
> - if (!ftd->type)
> + if (!ftd->type || *ftd->type == NULL_TREE)
> continue;
> if (matching_type_p (*ftd->type, effective_arg_type))
> {
> Index: gcc/c-family/c-lex.c
> ===================================================================
> --- gcc/c-family/c-lex.c (revision 278603)
> +++ gcc/c-family/c-lex.c (working copy)
> @@ -877,7 +877,12 @@ interpret_float (const cpp_token *token, unsigned
>
> /* Decode type based on width and properties. */
> if (flags & CPP_N_DFLOAT)
> - if ((flags & CPP_N_WIDTH) == CPP_N_LARGE)
> + if (!targetm.decimal_float_supported_p ())
> + {
> + error ("decimal floating-point not supported for this target");
> + return error_mark_node;
> + }
> + else if ((flags & CPP_N_WIDTH) == CPP_N_LARGE)
> type = dfloat128_type_node;
> else if ((flags & CPP_N_WIDTH) == CPP_N_SMALL)
> type = dfloat32_type_node;
> Index: gcc/lto/lto-lang.c
> ===================================================================
> --- gcc/lto/lto-lang.c (revision 278603)
> +++ gcc/lto/lto-lang.c (working copy)
> @@ -1051,11 +1051,14 @@ lto_type_for_mode (machine_mode mode, int unsigned
> return build_vector_type_for_mode (inner_type, mode);
> }
>
> - if (mode == TYPE_MODE (dfloat32_type_node))
> + if (dfloat32_type_node != NULL_TREE
> + && mode == TYPE_MODE (dfloat32_type_node))
> return dfloat32_type_node;
> - if (mode == TYPE_MODE (dfloat64_type_node))
> + if (dfloat64_type_node != NULL_TREE
> + && mode == TYPE_MODE (dfloat64_type_node))
> return dfloat64_type_node;
> - if (mode == TYPE_MODE (dfloat128_type_node))
> + if (dfloat128_type_node != NULL_TREE
> + && mode == TYPE_MODE (dfloat128_type_node))
> return dfloat128_type_node;
>
> if (ALL_SCALAR_FIXED_POINT_MODE_P (mode))
> Index: gcc/testsuite/gcc.dg/c2x-no-dfp-1.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/c2x-no-dfp-1.c (nonexistent)
> +++ gcc/testsuite/gcc.dg/c2x-no-dfp-1.c (working copy)
> @@ -0,0 +1,12 @@
> +/* Test DFP types and constants rejected if no DFP support. Bug
> + 91985. */
> +/* { dg-do compile { target { ! dfp } } } */
> +/* { dg-options "-std=c2x" } */
> +
> +_Decimal32 d32a; /* { dg-error "not supported" } */
> +_Decimal64 d64a; /* { dg-error "not supported" } */
> +_Decimal128 d128a; /* { dg-error "not supported" } */
> +
> +_Bool d32b = 1.0DF; /* { dg-error "not supported" } */
> +_Bool d64b = 1.0DD; /* { dg-error "not supported" } */
> +_Bool d128b = 1.0DL; /* { dg-error "not supported" } */
> Index: gcc/testsuite/gcc.dg/fltconst-pedantic-dfp.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/fltconst-pedantic-dfp.c (revision 278603)
> +++ gcc/testsuite/gcc.dg/fltconst-pedantic-dfp.c (working copy)
> @@ -2,5 +2,8 @@
> /* { dg-options "-pedantic" } */
>
> double a = 1.dl; /* { dg-warning "decimal float" } */
> +/* { dg-error "not supported for this target" "not supported" { target { !
> dfp } } .-1 } */
> double b = 1.df; /* { dg-warning "decimal float" } */
> +/* { dg-error "not supported for this target" "not supported" { target { !
> dfp } } .-1 } */
> double c = 1.dd; /* { dg-warning "decimal float" } */
> +/* { dg-error "not supported for this target" "not supported" { target { !
> dfp } } .-1 } */
> Index: gcc/testsuite/gcc.dg/gnu2x-builtins-no-dfp-1.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/gnu2x-builtins-no-dfp-1.c (nonexistent)
> +++ gcc/testsuite/gcc.dg/gnu2x-builtins-no-dfp-1.c (working copy)
> @@ -0,0 +1,18 @@
> +/* Test C2x built-in functions: test DFP built-in functions are not
> + available when no DFP support. Bug 91985. */
> +/* { dg-do compile { target { ! dfp } } } */
> +/* { dg-options "-std=gnu2x" } */
> +
> +int fabsd32 (void);
> +int fabsd64 (void);
> +int fabsd128 (void);
> +int nand32 (void);
> +int nand64 (void);
> +int nand128 (void);
> +
> +__typeof__ (__builtin_fabsd32 (0)) d32; /* { dg-warning "implicit" } */
> +__typeof__ (__builtin_fabsd64 (0)) d64; /* { dg-warning "implicit" } */
> +__typeof__ (__builtin_fabsd128 (0)) d128; /* { dg-warning "implicit" } */
> +__typeof__ (__builtin_nand32 (0)) d32n; /* { dg-warning "implicit" } */
> +__typeof__ (__builtin_nand64 (0)) d64n; /* { dg-warning "implicit" } */
> +__typeof__ (__builtin_nand128 (0)) d128n; /* { dg-warning "implicit" } */
> Index: gcc/tree.c
> ===================================================================
> --- gcc/tree.c (revision 278603)
> +++ gcc/tree.c (working copy)
> @@ -10334,23 +10334,26 @@ build_common_tree_nodes (bool signed_char)
> uint64_type_node = make_or_reuse_type (64, 1);
>
> /* Decimal float types. */
> - dfloat32_type_node = make_node (REAL_TYPE);
> - TYPE_PRECISION (dfloat32_type_node) = DECIMAL32_TYPE_SIZE;
> - SET_TYPE_MODE (dfloat32_type_node, SDmode);
> - layout_type (dfloat32_type_node);
> - dfloat32_ptr_type_node = build_pointer_type (dfloat32_type_node);
> + if (targetm.decimal_float_supported_p ())
> + {
> + dfloat32_type_node = make_node (REAL_TYPE);
> + TYPE_PRECISION (dfloat32_type_node) = DECIMAL32_TYPE_SIZE;
> + SET_TYPE_MODE (dfloat32_type_node, SDmode);
> + layout_type (dfloat32_type_node);
> + dfloat32_ptr_type_node = build_pointer_type (dfloat32_type_node);
>
> - dfloat64_type_node = make_node (REAL_TYPE);
> - TYPE_PRECISION (dfloat64_type_node) = DECIMAL64_TYPE_SIZE;
> - SET_TYPE_MODE (dfloat64_type_node, DDmode);
> - layout_type (dfloat64_type_node);
> - dfloat64_ptr_type_node = build_pointer_type (dfloat64_type_node);
> + dfloat64_type_node = make_node (REAL_TYPE);
> + TYPE_PRECISION (dfloat64_type_node) = DECIMAL64_TYPE_SIZE;
> + SET_TYPE_MODE (dfloat64_type_node, DDmode);
> + layout_type (dfloat64_type_node);
> + dfloat64_ptr_type_node = build_pointer_type (dfloat64_type_node);
>
> - dfloat128_type_node = make_node (REAL_TYPE);
> - TYPE_PRECISION (dfloat128_type_node) = DECIMAL128_TYPE_SIZE;
> - SET_TYPE_MODE (dfloat128_type_node, TDmode);
> - layout_type (dfloat128_type_node);
> - dfloat128_ptr_type_node = build_pointer_type (dfloat128_type_node);
> + dfloat128_type_node = make_node (REAL_TYPE);
> + TYPE_PRECISION (dfloat128_type_node) = DECIMAL128_TYPE_SIZE;
> + SET_TYPE_MODE (dfloat128_type_node, TDmode);
> + layout_type (dfloat128_type_node);
> + dfloat128_ptr_type_node = build_pointer_type (dfloat128_type_node);
> + }
>
> complex_integer_type_node = build_complex_type (integer_type_node, true);
> complex_float_type_node = build_complex_type (float_type_node, true);
Grüße
Thomas
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