c/6358: GCC 3.1 ICE on statement expressions

[gbeauchesne at mandrakesoft dot com]

>Number:         6358
>Category:       c
>Synopsis:       GCC 3.1 ICE on statement expressions
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          ice-on-legal-code
>Submitter-Id:   net
>Arrival-Date:   Thu Apr 18 06:46:08 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Gwenole Beauchesne
>Release:        GNU C version 3.1 20020418 (prerelease) (i686-pc-linux-gnu)
>Organization:
>Environment:
i586-mandrake-linux-gnu
>Description:
gcc-3.1-branch ICEs on some statement expression returning void and enclosed in a function returning a value of floating type.

[gb@kernel gcc]$ ./cc1 ~/vrac/stmt_expr.c
 f
/home/gb/vrac/stmt_expr.c: In function `f':
/home/gb/vrac/stmt_expr.c:7: Internal compiler error in subst_stack_regs_pat, at reg-stack.c:1441
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://www.gnu.org/software/gcc/bugs.html> for instructions.
>How-To-Repeat:
You can compile the following testcase with or without any optimazations. The testcase came up while distilling a similar ICE for ggv 1.99.3 (bonobo/ggv-postscript-view.c).

void g();

double f()
{
  (void) ({ g(); return; });
  return 0.0;
}
>Fix:
The ICE does not occur if either return; of the statement expression is omitted or the return value of f() is changed to some other scalar (non floating) type.

Besides, this is a regression from gcc-3.0.4.

BTW, as far as I can tell, the enclosed testcase succeeds with
GNU C version 3.1 20010617 (experimental) (i686-pc-linux-gnu)

but fails with:
GNU C version 3.1 20010715 (experimental) (i686-pc-linux-gnu)
>Release-Note:
>Audit-Trail:
>Unformatted: