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[Bug rtl-optimization/63191] [4.8/4.9/5 Regression] 32-bit gcc uses excessive memory during dead store elimination with -fPIC
- From: "steven at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 07 Apr 2015 20:23:32 +0000
- Subject: [Bug rtl-optimization/63191] [4.8/4.9/5 Regression] 32-bit gcc uses excessive memory during dead store elimination with -fPIC
- Auto-submitted: auto-generated
- References: <bug-63191-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63191
--- Comment #4 from Steven Bosscher <steven at gcc dot gnu.org> ---
How is one to reproduce this bug with GCC5? I've tried:
$ ./xg++ --version
xg++ (GCC) 5.0.0 20150407 (experimental) [trunk revision 221906]
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ ./xg++ -B. -S -O2 -m32 -fPIC PR63191.cc -fdump-tree-optimized
$ cat PR63191.cc.190t.optimized
;; Function (static initializers for PR63191.cc) (_GLOBAL__sub_I_PR63191.cc,
funcdef_no=4, decl_uid=14028, cgraph_uid=4, symbol_order=1500) (executed once)
(static initializers for PR63191.cc) ()
{
<bb 2>:
return;
}
$
So AFAICT GCC5 optimizes the test case of comment #0 to an empty file.
I'm sure there's a way to avoid optimizing this to empty, but I'm not
quite a C++ guru ;-)