On Tue, Sep 01, 2020 at 05:33:43PM -0400, Jason Merrill via Gcc-patches wrote: > On 9/1/20 3:41 PM, Marek Polacek wrote: > > On Tue, Sep 01, 2020 at 03:27:36PM -0400, Jason Merrill via Gcc-patches > > wrote: > > > On 9/1/20 12:10 PM, Marek Polacek wrote: > > > > Currently, we allow new char[]{"foo"}, but not new char[4]{"foo"}. > > > > We should accept the latter too: [dcl.init.list]p3.3 says to treat > > > > this as [dcl.init.string]. > > > > > > > > We were rejecting this code because we never called reshape_init before > > > > the digest_init in build_new_1. reshape_init handles [dcl.init.string] > > > > by unwrapping the STRING_CST from its enclosing { }, and digest_init > > > > assumes that reshape_init has been called for aggregates anyway, and an > > > > array is an aggregate. > > > > > > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? > > > > > > > > gcc/cp/ChangeLog: > > > > > > > > PR c++/77841 > > > > * init.c (build_new_1): Call reshape_init. > > > > > > > > gcc/testsuite/ChangeLog: > > > > > > > > PR c++/77841 > > > > * g++.dg/cpp0x/initlist-new4.C: New test. > > > > --- > > > > gcc/cp/init.c | 6 ++++++ > > > > gcc/testsuite/g++.dg/cpp0x/initlist-new4.C | 6 ++++++ > > > > 2 files changed, 12 insertions(+) > > > > create mode 100644 gcc/testsuite/g++.dg/cpp0x/initlist-new4.C > > > > > > > > diff --git a/gcc/cp/init.c b/gcc/cp/init.c > > > > index 360ab8c0b52..d4540db3605 100644 > > > > --- a/gcc/cp/init.c > > > > +++ b/gcc/cp/init.c > > > > @@ -3575,6 +3575,12 @@ build_new_1 (vec<tree, va_gc> **placement, tree > > > > type, tree nelts, > > > > /* We'll check the length at runtime. */ > > > > domain = NULL_TREE; > > > > arraytype = build_cplus_array_type (type, domain); > > > > + /* If we have new char[4]{"foo"}, we have to reshape > > > > + so that the STRING_CST isn't wrapped in { }. */ > > > > + vecinit = reshape_init (arraytype, vecinit, complain); > > > > + /* The middle end doesn't cope with the location > > > > wrapper > > > > + around a STRING_CST. */ > > > > + STRIP_ANY_LOCATION_WRAPPER (vecinit); > > > > vecinit = digest_init (arraytype, vecinit, complain); > > > > } > > > > > > This is OK, but now I wonder why your earlier addition, > > > > > > > /* This handles code like new char[]{"foo"}. */ > > > > else if (len == 1 > > > > && char_type_p (TYPE_MAIN_VARIANT (type)) > > > > && TREE_CODE (tree_strip_any_location_wrapper > > > > ((**init)[0])) > > > > == STRING_CST) > > > > { > > > > vecinit = (**init)[0]; > > > > STRIP_ANY_LOCATION_WRAPPER (vecinit); > > > > } > > > > > > isn't handled by the block you're changing in this patch. Why isn't > > > DIRECT_LIST_INIT_P true for new char[]{"foo"}? > > > > Yes, I was hoping this hunk would handle the new char[4]{"foo"} case too, > > but for new char[]{"foo"} DIRECT_LIST_INIT_P is false because earlier in > > build_new we called reshape_init: > > > > 4011 /* Otherwise we should have 'new T[]{e_0, ..., e_k}'. */ > > 4012 if (BRACE_ENCLOSED_INITIALIZER_P (elt)) > > 4013 elt = reshape_init (type, elt, complain); > > > > which unwraps the { } from {"foo"}, so it's no longer a list init. > > Ah, I see. > > > We > > won't get there with new char[4]{"foo"} because TREE_CODE (type) will > > not be ARRAY_TYPE; instead, nelts is set to INTEGER_CST 4 when we know > > the array bound. > > > > I could make it so that we call reshape_init in build_new for the [4] > > case too, but it was uglier than this fix. > > > > Should I go ahead with this patch as-is or would you prefer any changes? > > Go ahead with this for now, but I notice that we also still don't support
Pushed. > new char[4](1,2,3,4); > > because the handling of parenthesized-init is limited to the deduced array > size case. Ah, that should work. And conversely here I'd expect an error: new char[2]("so_sad"); but we don't give any. > It would be nice to find a way to combine the two places that we're messing > with array initializers. I'll look into that. Thanks, Marek