Message ID | 20201008204710.2592641-1-ppalka@redhat.com |
---|---|
State | New |
Headers | show |
Series | c++: Handle RANGE_EXPR indexes in init_subob_ctx [PR97328] | expand |
On Thu, 8 Oct 2020, Patrick Palka wrote: > In the testcase below, we're ICEing during constexpr evaluation of the > CONSTRUCTOR {.data={{}, [1 ... 7]={}}} of type 'vector'. The apparently > unique thing about this CONSTRUCTOR is that it has a RANGE_EXPR index > whose corresponding sub-aggregate initializer doesn't satisfy > reduced_constant_expression_p (because its field 't' is uninitialized). > > This is a problem because init_subob_ctx currently punts if the > constructor index is a RANGE_EXPR, so when cxx_eval_bare_aggregate > recurses into this sub-aggregate initializer we trip over the > same_type_p assert in verify_ctor_sanity. > > Fix this by making init_subob_ctx set up an appropriate sub-aggregate > initialization context even when the index is a RANGE_EXPR. > > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for > trunk and the 10 branch? > > gcc/cp/ChangeLog: > > PR c++/97328 > * constexpr.c (init_subob_ctx): Don't punt if the index is a > RANGE_EXPR, instead build a sub-aggregate initialization context > with no subobject. > > gcc/testsuite/ChangeLog: > > PR c++/97328 > * g++.dg/cpp2a/constexpr-init19.C: New test. > * g++.dg/cpp2a/constexpr-init20.C: New test. Ping. > --- > gcc/cp/constexpr.c | 13 +++++++------ > gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C | 15 +++++++++++++++ > gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C | 15 +++++++++++++++ > 3 files changed, 37 insertions(+), 6 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C > create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C > > diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c > index a118f8a810b..e50a2a220cb 100644 > --- a/gcc/cp/constexpr.c > +++ b/gcc/cp/constexpr.c > @@ -3953,11 +3953,6 @@ init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, > { > new_ctx = *ctx; > > - if (index && TREE_CODE (index) != INTEGER_CST > - && TREE_CODE (index) != FIELD_DECL) > - /* This won't have an element in the new CONSTRUCTOR. */ > - return; > - > tree type = initialized_type (value); > if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) > /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ > @@ -3967,7 +3962,13 @@ init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, > update object to refer to the subobject and ctor to refer to > the (newly created) sub-initializer. */ > if (ctx->object) > - new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); > + { > + if (index == NULL_TREE || TREE_CODE (index) == RANGE_EXPR) > + /* There's no well-defined subobject for this index. */ > + new_ctx.object = NULL_TREE; > + else > + new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); > + } > tree elt = build_constructor (type, NULL); > CONSTRUCTOR_NO_CLEARING (elt) = true; > new_ctx.ctor = elt; > diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C > new file mode 100644 > index 00000000000..d354c5ad609 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C > @@ -0,0 +1,15 @@ > +// PR c++/97328 > +// { dg-do compile { target c++20 } } > + > +struct vector { > + struct storage { > + int t; > + constexpr storage() {} > + } data[8]; > +}; > + > +constexpr auto foo() { > + vector i; > + return i; > +} > +auto val = foo(); > diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C > new file mode 100644 > index 00000000000..1a6ed8d86dd > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C > @@ -0,0 +1,15 @@ > +// PR c++/97328 > +// { dg-do compile { target c++20 } } > + > +struct vector { > + union storage { > + int t; > + constexpr storage() {} > + } data[8]; > +}; > + > +constexpr auto foo() { > + vector i; > + return i; > +} > +auto val = foo(); > -- > 2.29.0.rc0 > >
On 10/8/20 4:47 PM, Patrick Palka wrote: > In the testcase below, we're ICEing during constexpr evaluation of the > CONSTRUCTOR {.data={{}, [1 ... 7]={}}} of type 'vector'. The apparently > unique thing about this CONSTRUCTOR is that it has a RANGE_EXPR index > whose corresponding sub-aggregate initializer doesn't satisfy > reduced_constant_expression_p (because its field 't' is uninitialized). > > This is a problem because init_subob_ctx currently punts if the > constructor index is a RANGE_EXPR, so when cxx_eval_bare_aggregate > recurses into this sub-aggregate initializer we trip over the > same_type_p assert in verify_ctor_sanity. > > Fix this by making init_subob_ctx set up an appropriate sub-aggregate > initialization context even when the index is a RANGE_EXPR. > > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for > trunk and the 10 branch? > > gcc/cp/ChangeLog: > > PR c++/97328 > * constexpr.c (init_subob_ctx): Don't punt if the index is a > RANGE_EXPR, instead build a sub-aggregate initialization context > with no subobject. > > gcc/testsuite/ChangeLog: > > PR c++/97328 > * g++.dg/cpp2a/constexpr-init19.C: New test. > * g++.dg/cpp2a/constexpr-init20.C: New test. > --- > gcc/cp/constexpr.c | 13 +++++++------ > gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C | 15 +++++++++++++++ > gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C | 15 +++++++++++++++ > 3 files changed, 37 insertions(+), 6 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C > create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C > > diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c > index a118f8a810b..e50a2a220cb 100644 > --- a/gcc/cp/constexpr.c > +++ b/gcc/cp/constexpr.c > @@ -3953,11 +3953,6 @@ init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, > { > new_ctx = *ctx; > > - if (index && TREE_CODE (index) != INTEGER_CST > - && TREE_CODE (index) != FIELD_DECL) > - /* This won't have an element in the new CONSTRUCTOR. */ > - return; Hmm, I wonder what this was trying to exclude? I'd be more comfortable adding RANGE_EXPR to the allowed index codes. > tree type = initialized_type (value); > if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) > /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ > @@ -3967,7 +3962,13 @@ init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, > update object to refer to the subobject and ctor to refer to > the (newly created) sub-initializer. */ > if (ctx->object) > - new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); > + { > + if (index == NULL_TREE || TREE_CODE (index) == RANGE_EXPR) > + /* There's no well-defined subobject for this index. */ > + new_ctx.object = NULL_TREE; > + else > + new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); > + } > tree elt = build_constructor (type, NULL); > CONSTRUCTOR_NO_CLEARING (elt) = true; > new_ctx.ctor = elt; > diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C > new file mode 100644 > index 00000000000..d354c5ad609 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C > @@ -0,0 +1,15 @@ > +// PR c++/97328 > +// { dg-do compile { target c++20 } } > + > +struct vector { > + struct storage { > + int t; > + constexpr storage() {} > + } data[8]; > +}; > + > +constexpr auto foo() { > + vector i; > + return i; > +} > +auto val = foo(); > diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C > new file mode 100644 > index 00000000000..1a6ed8d86dd > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C > @@ -0,0 +1,15 @@ > +// PR c++/97328 > +// { dg-do compile { target c++20 } } > + > +struct vector { > + union storage { > + int t; > + constexpr storage() {} > + } data[8]; > +}; > + > +constexpr auto foo() { > + vector i; > + return i; > +} > +auto val = foo(); >
On Wed, 21 Oct 2020, Jason Merrill wrote: > On 10/8/20 4:47 PM, Patrick Palka wrote: > > In the testcase below, we're ICEing during constexpr evaluation of the > > CONSTRUCTOR {.data={{}, [1 ... 7]={}}} of type 'vector'. The apparently > > unique thing about this CONSTRUCTOR is that it has a RANGE_EXPR index > > whose corresponding sub-aggregate initializer doesn't satisfy > > reduced_constant_expression_p (because its field 't' is uninitialized). > > > > This is a problem because init_subob_ctx currently punts if the > > constructor index is a RANGE_EXPR, so when cxx_eval_bare_aggregate > > recurses into this sub-aggregate initializer we trip over the > > same_type_p assert in verify_ctor_sanity. > > > > Fix this by making init_subob_ctx set up an appropriate sub-aggregate > > initialization context even when the index is a RANGE_EXPR. > > > > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for > > trunk and the 10 branch? > > > > gcc/cp/ChangeLog: > > > > PR c++/97328 > > * constexpr.c (init_subob_ctx): Don't punt if the index is a > > RANGE_EXPR, instead build a sub-aggregate initialization context > > with no subobject. > > > > gcc/testsuite/ChangeLog: > > > > PR c++/97328 > > * g++.dg/cpp2a/constexpr-init19.C: New test. > > * g++.dg/cpp2a/constexpr-init20.C: New test. > > --- > > gcc/cp/constexpr.c | 13 +++++++------ > > gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C | 15 +++++++++++++++ > > gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C | 15 +++++++++++++++ > > 3 files changed, 37 insertions(+), 6 deletions(-) > > create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C > > create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C > > > > diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c > > index a118f8a810b..e50a2a220cb 100644 > > --- a/gcc/cp/constexpr.c > > +++ b/gcc/cp/constexpr.c > > @@ -3953,11 +3953,6 @@ init_subob_ctx (const constexpr_ctx *ctx, > > constexpr_ctx &new_ctx, > > { > > new_ctx = *ctx; > > - if (index && TREE_CODE (index) != INTEGER_CST > > - && TREE_CODE (index) != FIELD_DECL) > > - /* This won't have an element in the new CONSTRUCTOR. */ > > - return; > > Hmm, I wonder what this was trying to exclude? I'd be more comfortable adding > RANGE_EXPR to the allowed index codes. Ah, it's probably COMPONENT_REF, NOP_EXPR and/or POINTER_PLUS_EXPR. I missed that cxx_eval_bare_aggregate explicitly checks for such indexes. Here's a patch which refines the above check rather than removing it entirely. Does it look OK for 10/trunk after testing? -- >8 -- Subject: [PATCH] c++: Handle RANGE_EXPR index in init_subob_ctx [PR97328] In the testcase below, we're ICEing during constexpr evaluation of the CONSTRUCTOR {.data={{}, [1 ... 7]={}}} of type 'vector'. The interesting thing about this CONSTRUCTOR is that it has a RANGE_EXPR index for an element initializer which doesn't satisfy reduced_constant_expression_p (because the field 't' is uninitialized). This is a problem because init_subob_ctx currently punts on setting up a sub-aggregate initialization context when given a RANGE_EXPR index, so we later trip over the asserts in verify_ctor_sanity when recursing into cxx_eval_bare_aggregate on this element initializer. Fix this by making init_subob_ctx set up an appropriate initialization context when given a RANGE_EXPR index. gcc/cp/ChangeLog: PR c++/97328 * constexpr.c (init_subob_ctx): Don't punt on RANGE_EXPR indexes, instead build a sub-aggregate initialization context with no subobject. gcc/testsuite/ChangeLog: PR c++/97328 * g++.dg/cpp2a/constexpr-init19.C: New test. * g++.dg/cpp2a/constexpr-init20.C: New test. --- gcc/cp/constexpr.c | 11 +++++++++-- gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C | 15 +++++++++++++++ gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C | 15 +++++++++++++++ 3 files changed, 39 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index a118f8a810b..cb3c787094c 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -3954,7 +3954,8 @@ init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, new_ctx = *ctx; if (index && TREE_CODE (index) != INTEGER_CST - && TREE_CODE (index) != FIELD_DECL) + && TREE_CODE (index) != FIELD_DECL + && TREE_CODE (index) != RANGE_EXPR) /* This won't have an element in the new CONSTRUCTOR. */ return; @@ -3967,7 +3968,13 @@ init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, update object to refer to the subobject and ctor to refer to the (newly created) sub-initializer. */ if (ctx->object) - new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); + { + if (index == NULL_TREE || TREE_CODE (index) == RANGE_EXPR) + /* There's no well-defined subobject for this index. */ + new_ctx.object = NULL_TREE; + else + new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); + } tree elt = build_constructor (type, NULL); CONSTRUCTOR_NO_CLEARING (elt) = true; new_ctx.ctor = elt; diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C new file mode 100644 index 00000000000..d354c5ad609 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C @@ -0,0 +1,15 @@ +// PR c++/97328 +// { dg-do compile { target c++20 } } + +struct vector { + struct storage { + int t; + constexpr storage() {} + } data[8]; +}; + +constexpr auto foo() { + vector i; + return i; +} +auto val = foo(); diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C new file mode 100644 index 00000000000..1a6ed8d86dd --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C @@ -0,0 +1,15 @@ +// PR c++/97328 +// { dg-do compile { target c++20 } } + +struct vector { + union storage { + int t; + constexpr storage() {} + } data[8]; +}; + +constexpr auto foo() { + vector i; + return i; +} +auto val = foo();
On 10/21/20 5:46 PM, Patrick Palka wrote: > On Wed, 21 Oct 2020, Jason Merrill wrote: > >> On 10/8/20 4:47 PM, Patrick Palka wrote: >>> In the testcase below, we're ICEing during constexpr evaluation of the >>> CONSTRUCTOR {.data={{}, [1 ... 7]={}}} of type 'vector'. The apparently >>> unique thing about this CONSTRUCTOR is that it has a RANGE_EXPR index >>> whose corresponding sub-aggregate initializer doesn't satisfy >>> reduced_constant_expression_p (because its field 't' is uninitialized). >>> >>> This is a problem because init_subob_ctx currently punts if the >>> constructor index is a RANGE_EXPR, so when cxx_eval_bare_aggregate >>> recurses into this sub-aggregate initializer we trip over the >>> same_type_p assert in verify_ctor_sanity. >>> >>> Fix this by making init_subob_ctx set up an appropriate sub-aggregate >>> initialization context even when the index is a RANGE_EXPR. >>> >>> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for >>> trunk and the 10 branch? >>> >>> gcc/cp/ChangeLog: >>> >>> PR c++/97328 >>> * constexpr.c (init_subob_ctx): Don't punt if the index is a >>> RANGE_EXPR, instead build a sub-aggregate initialization context >>> with no subobject. >>> >>> gcc/testsuite/ChangeLog: >>> >>> PR c++/97328 >>> * g++.dg/cpp2a/constexpr-init19.C: New test. >>> * g++.dg/cpp2a/constexpr-init20.C: New test. >>> --- >>> gcc/cp/constexpr.c | 13 +++++++------ >>> gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C | 15 +++++++++++++++ >>> gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C | 15 +++++++++++++++ >>> 3 files changed, 37 insertions(+), 6 deletions(-) >>> create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C >>> create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C >>> >>> diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c >>> index a118f8a810b..e50a2a220cb 100644 >>> --- a/gcc/cp/constexpr.c >>> +++ b/gcc/cp/constexpr.c >>> @@ -3953,11 +3953,6 @@ init_subob_ctx (const constexpr_ctx *ctx, >>> constexpr_ctx &new_ctx, >>> { >>> new_ctx = *ctx; >>> - if (index && TREE_CODE (index) != INTEGER_CST >>> - && TREE_CODE (index) != FIELD_DECL) >>> - /* This won't have an element in the new CONSTRUCTOR. */ >>> - return; >> >> Hmm, I wonder what this was trying to exclude? I'd be more comfortable adding >> RANGE_EXPR to the allowed index codes. > > Ah, it's probably COMPONENT_REF, NOP_EXPR and/or POINTER_PLUS_EXPR. > I missed that cxx_eval_bare_aggregate explicitly checks for such > indexes. > > Here's a patch which refines the above check rather than removing it > entirely. Does it look OK for 10/trunk after testing? OK. > -- >8 -- > > Subject: [PATCH] c++: Handle RANGE_EXPR index in init_subob_ctx [PR97328] > > In the testcase below, we're ICEing during constexpr evaluation of the > CONSTRUCTOR {.data={{}, [1 ... 7]={}}} of type 'vector'. The interesting > thing about this CONSTRUCTOR is that it has a RANGE_EXPR index for an > element initializer which doesn't satisfy reduced_constant_expression_p > (because the field 't' is uninitialized). > > This is a problem because init_subob_ctx currently punts on setting up a > sub-aggregate initialization context when given a RANGE_EXPR index, so > we later trip over the asserts in verify_ctor_sanity when recursing into > cxx_eval_bare_aggregate on this element initializer. > > Fix this by making init_subob_ctx set up an appropriate initialization > context when given a RANGE_EXPR index. > > gcc/cp/ChangeLog: > > PR c++/97328 > * constexpr.c (init_subob_ctx): Don't punt on RANGE_EXPR > indexes, instead build a sub-aggregate initialization context > with no subobject. > > gcc/testsuite/ChangeLog: > > PR c++/97328 > * g++.dg/cpp2a/constexpr-init19.C: New test. > * g++.dg/cpp2a/constexpr-init20.C: New test. > --- > gcc/cp/constexpr.c | 11 +++++++++-- > gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C | 15 +++++++++++++++ > gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C | 15 +++++++++++++++ > 3 files changed, 39 insertions(+), 2 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C > create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C > > diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c > index a118f8a810b..cb3c787094c 100644 > --- a/gcc/cp/constexpr.c > +++ b/gcc/cp/constexpr.c > @@ -3954,7 +3954,8 @@ init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, > new_ctx = *ctx; > > if (index && TREE_CODE (index) != INTEGER_CST > - && TREE_CODE (index) != FIELD_DECL) > + && TREE_CODE (index) != FIELD_DECL > + && TREE_CODE (index) != RANGE_EXPR) > /* This won't have an element in the new CONSTRUCTOR. */ > return; > > @@ -3967,7 +3968,13 @@ init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, > update object to refer to the subobject and ctor to refer to > the (newly created) sub-initializer. */ > if (ctx->object) > - new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); > + { > + if (index == NULL_TREE || TREE_CODE (index) == RANGE_EXPR) > + /* There's no well-defined subobject for this index. */ > + new_ctx.object = NULL_TREE; > + else > + new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); > + } > tree elt = build_constructor (type, NULL); > CONSTRUCTOR_NO_CLEARING (elt) = true; > new_ctx.ctor = elt; > diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C > new file mode 100644 > index 00000000000..d354c5ad609 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C > @@ -0,0 +1,15 @@ > +// PR c++/97328 > +// { dg-do compile { target c++20 } } > + > +struct vector { > + struct storage { > + int t; > + constexpr storage() {} > + } data[8]; > +}; > + > +constexpr auto foo() { > + vector i; > + return i; > +} > +auto val = foo(); > diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C > new file mode 100644 > index 00000000000..1a6ed8d86dd > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C > @@ -0,0 +1,15 @@ > +// PR c++/97328 > +// { dg-do compile { target c++20 } } > + > +struct vector { > + union storage { > + int t; > + constexpr storage() {} > + } data[8]; > +}; > + > +constexpr auto foo() { > + vector i; > + return i; > +} > +auto val = foo(); >
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index a118f8a810b..e50a2a220cb 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -3953,11 +3953,6 @@ init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, { new_ctx = *ctx; - if (index && TREE_CODE (index) != INTEGER_CST - && TREE_CODE (index) != FIELD_DECL) - /* This won't have an element in the new CONSTRUCTOR. */ - return; - tree type = initialized_type (value); if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ @@ -3967,7 +3962,13 @@ init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, update object to refer to the subobject and ctor to refer to the (newly created) sub-initializer. */ if (ctx->object) - new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); + { + if (index == NULL_TREE || TREE_CODE (index) == RANGE_EXPR) + /* There's no well-defined subobject for this index. */ + new_ctx.object = NULL_TREE; + else + new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); + } tree elt = build_constructor (type, NULL); CONSTRUCTOR_NO_CLEARING (elt) = true; new_ctx.ctor = elt; diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C new file mode 100644 index 00000000000..d354c5ad609 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init19.C @@ -0,0 +1,15 @@ +// PR c++/97328 +// { dg-do compile { target c++20 } } + +struct vector { + struct storage { + int t; + constexpr storage() {} + } data[8]; +}; + +constexpr auto foo() { + vector i; + return i; +} +auto val = foo(); diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C new file mode 100644 index 00000000000..1a6ed8d86dd --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init20.C @@ -0,0 +1,15 @@ +// PR c++/97328 +// { dg-do compile { target c++20 } } + +struct vector { + union storage { + int t; + constexpr storage() {} + } data[8]; +}; + +constexpr auto foo() { + vector i; + return i; +} +auto val = foo();