[Bug c++/98480] New: [coroutines] ICE on co_await in for-loop end condition.

[Bug c++/98480] New: [coroutines] ICE on co_await in for-loop end condition.

[dpsicilia at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98480

            Bug ID: 98480
           Summary: [coroutines] ICE on co_await in for-loop end
                    condition.
           Product: gcc
           Version: 10.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dpsicilia at gmail dot com
  Target Milestone: ---

Quick Minimal reproducer: https://godbolt.org/z/Wrv54E

--------------------------------------------------------

Summary: when a co_await is placed in the end condition
of a for loop it causes gcc to ICE.  If I pull the
co_await out and store the result in a variable then the
issue goes away.

--------------------------------------------------------

Version of GCC: 10.2.0
System type: Linux x64
Command line: -std=c++20 -fcoroutines
Compiler output: ICE (see godbolt link; full stack trace below).

--------------------------------------------------------

// Standalone reproducer (same as godbolt link above).
#include <coroutine>

struct future {
  struct promise_type {
    void return_value(int) {}
    auto initial_suspend() { return std::suspend_never{}; }
    auto final_suspend() { return std::suspend_never{}; }
    void unhandled_exception() {}
    future get_return_object() { return {}; }
  };
  bool await_ready() { return true; }
  void await_suspend(std::coroutine_handle<>) {}
  int await_resume() { return 0; }
};

future co_foo() {
  for( int i = 0; i < co_await future{}; ++i );
  // ICE -------------^
  co_return 0;
}

--------------------------------------------------------

reproducer.cpp: In function ‘void
_Z6co_foov.actor(co_foo()::_Z6co_foov.frame*)’:
reproducer.cpp:17:3: internal compiler error: in fold_convert_loc, at
fold-const.c:2435
  285 |   for( int i = 0; i < co_await future{}; ++i )
      |   ^~~
0x5fd0ae fold_convert_loc(unsigned int, tree_node*, tree_node*)
        ../../gcc/fold-const.c:2435
0x9fae2a gimplify_cond_expr
        ../../gcc/gimplify.c:4149
0x9f2f1b gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:13513
0x9f3705 gimplify_stmt(tree_node**, gimple**)
        ../../gcc/gimplify.c:6825
0x9f3705 gimplify_statement_list
        ../../gcc/gimplify.c:1869
0x9f3705 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:14000
0x9f64f9 gimplify_stmt(tree_node**, gimple**)
        ../../gcc/gimplify.c:6825
0x9f64f9 gimplify_and_add(tree_node*, gimple**)
        ../../gcc/gimplify.c:486
0x9f64f9 gimplify_loop_expr
        ../../gcc/gimplify.c:1843
0x9f37b6 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:13761
0x9f3705 gimplify_stmt(tree_node**, gimple**)
        ../../gcc/gimplify.c:6825
0x9f3705 gimplify_statement_list
        ../../gcc/gimplify.c:1869
0x9f3705 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:14000
0x9f3705 gimplify_stmt(tree_node**, gimple**)
        ../../gcc/gimplify.c:6825
0x9f3705 gimplify_statement_list
        ../../gcc/gimplify.c:1869
0x9f3705 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:14000
0x9f9849 gimplify_stmt(tree_node**, gimple**)
        ../../gcc/gimplify.c:6825
0x9f9849 gimplify_bind_expr
        ../../gcc/gimplify.c:1424
0x9f3102 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:13757
0x9f3705 gimplify_stmt(tree_node**, gimple**)
        ../../gcc/gimplify.c:6825
Please submit a full bug report,

[Bug c++/98480] [coroutines] ICE on co_await in for-loop end condition.

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98480

Iain Sandoe <iains at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |iains at gcc dot gnu.org
   Last reconfirmed|                            |2021-03-12
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1

--- Comment #1 from Iain Sandoe <iains at gcc dot gnu.org> ---
Created attachment 50375
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50375&action=edit
Patch under test

I seem to have had a brainstorm when applying the changes needed for do {}
while; and while () {} and omitted the ones for for.

[Bug c++/98480] [coroutines] ICE on co_await in for-loop end condition.

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98480

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Iain D Sandoe <iains@gcc.gnu.org>:

https://gcc.gnu.org/g:26e0eb1071e318728bcd33f28d055729ac48792c

commit r11-7675-g26e0eb1071e318728bcd33f28d055729ac48792c
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Thu Mar 11 14:22:37 2021 +0000

    coroutines : Handle for await expressions in for stmts [PR98480].

    The handling of await expressions in the init, condition and iteration
    expressions of for loops had been omitted.  Fixed thus.

    gcc/cp/ChangeLog:

            PR c++/98480
            * coroutines.cc (replace_continue): Rewrite continue into
            'goto label'.
            (await_statement_walker): Handle await expressions in the
            initializer, condition and iteration expressions of for
            loops.

    gcc/testsuite/ChangeLog:

            PR c++/98480
            * g++.dg/coroutines/pr98480.C: New test.
            * g++.dg/coroutines/torture/co-await-24-for-init.C: New test.
            * g++.dg/coroutines/torture/co-await-25-for-condition.C: New test.
            * g++.dg/coroutines/torture/co-await-26-for-iteration-expr.C: New
test.

[Bug c++/98480] [coroutines] ICE on co_await in for-loop end condition.

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98480

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Iain D Sandoe
<iains@gcc.gnu.org>:

https://gcc.gnu.org/g:c38db3729b9a895a8dcf3ef28924822b28ad5c01

commit r10-9516-gc38db3729b9a895a8dcf3ef28924822b28ad5c01
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Thu Mar 11 14:22:37 2021 +0000

    coroutines : Handle for await expressions in for stmts [PR98480].

    The handling of await expressions in the init, condition and iteration
    expressions of for loops had been omitted.  Fixed thus.

    gcc/cp/ChangeLog:

            PR c++/98480
            * coroutines.cc (replace_continue): Rewrite continue into
            'goto label'.
            (await_statement_walker): Handle await expressions in the
            initializer, condition and iteration expressions of for
            loops.

    gcc/testsuite/ChangeLog:

            PR c++/98480
            * g++.dg/coroutines/pr98480.C: New test.
            * g++.dg/coroutines/torture/co-await-24-for-init.C: New test.
            * g++.dg/coroutines/torture/co-await-25-for-condition.C: New test.
            * g++.dg/coroutines/torture/co-await-26-for-iteration-expr.C: New
test.

    (cherry picked from commit 26e0eb1071e318728bcd33f28d055729ac48792c)

[Bug c++/98480] [coroutines] ICE on co_await in for-loop end condition.

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98480

Iain Sandoe <iains at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #4 from Iain Sandoe <iains at gcc dot gnu.org> ---
fixed for master and 10.3.