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[Bug rtl-optimization/51447] [4.6/4.7 Regression] global register variable definition incorrectly removed as dead code
- From: "howarth at nitro dot med.uc.edu" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Sun, 20 Jan 2013 22:18:04 +0000
- Subject: [Bug rtl-optimization/51447] [4.6/4.7 Regression] global register variable definition incorrectly removed as dead code
- Auto-submitted: auto-generated
- References: <bug-51447-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51447
Jack Howarth <howarth at nitro dot med.uc.edu> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |howarth at nitro dot
| |med.uc.edu
--- Comment #16 from Jack Howarth <howarth at nitro dot med.uc.edu> 2013-01-20 22:18:04 UTC ---
The test case gcc.c-torture/execute/pr51447.c fails its execution test at -m32
(but not -m64) on x86_64-apple-darwin12 in gcc trunk. Adding -fno-PIC to the
compile flags eliminates the execution failure at all optimization levels for
-m32 on x86_64-apple-darwin12.
# gdb ./pr51447.x0
GNU gdb 6.3.50-20050815 (Apple version gdb-1822) (Sun Aug 5 03:00:42 UTC 2012)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "x86_64-apple-darwin"...Reading symbols for shared
libraries ... done
(gdb) b main
Breakpoint 1 at 0x1eed: file
/sw/src/fink.build/gcc48-4.8.0-1000/gcc-4.8-20130120/gcc/testsuite/gcc.c-torture/execute/pr51447.c,
line 13.
Breakpoint 2 at 0x1ec8: file
/sw/src/fink.build/gcc48-4.8.0-1000/gcc-4.8-20130120/gcc/testsuite/gcc.c-torture/execute/pr51447.c,
line 18.
warning: Multiple breakpoints were set.
Use the "delete" command to delete unwanted breakpoints.
(gdb) disp/i $pc
(gdb) r
Starting program:
/sw/src/fink.build/gcc48-4.8.0-1000/darwin_objdir/gcc/testsuite/gcc/pr51447.x0
warning: posix_spawn failed, trying execvp, error: 86
Reading symbols for shared libraries ++......................... done
Breakpoint 1, 0x00001eed in main () at
/sw/src/fink.build/gcc48-4.8.0-1000/gcc-4.8-20130120/gcc/testsuite/gcc.c-torture/execute/pr51447.c:13
13 {
1: x/i $pc 0x1eed <main+9>: call 0x1f3e <__x86.get_pc_thunk.bx>
(gdb) si
0x00001f3e in __x86.get_pc_thunk.bx ()
1: x/i $pc 0x1f3e <__x86.get_pc_thunk.bx>: mov (%esp),%ebx
(gdb)
0x00001f41 in __x86.get_pc_thunk.bx ()
1: x/i $pc 0x1f41 <__x86.get_pc_thunk.bx+3>: ret
(gdb)
0x00001ef2 in main () at
/sw/src/fink.build/gcc48-4.8.0-1000/gcc-4.8-20130120/gcc/testsuite/gcc.c-torture/execute/pr51447.c:13
13 {
1: x/i $pc 0x1ef2 <main+14>: lea -0x18(%ebp),%eax
(gdb)
0x00001ef5 13 {
1: x/i $pc 0x1ef5 <main+17>: mov %eax,-0x24(%ebp)
(gdb)
0x00001ef8 13 {
1: x/i $pc 0x1ef8 <main+20>: mov %esp,-0x20(%ebp)
(gdb)
21 bar (&&nonlocal_lab);
1: x/i $pc 0x1efb <main+23>: lea -0x24(%ebp),%eax
(gdb)
0x00001efe 21 bar (&&nonlocal_lab);
1: x/i $pc 0x1efe <main+26>: lea 0x26(%ebx),%edx
(gdb)
0x00001f04 21 bar (&&nonlocal_lab);
1: x/i $pc 0x1f04 <main+32>: mov %edx,(%esp)
(gdb)
0x00001f07 21 bar (&&nonlocal_lab);
1: x/i $pc 0x1f07 <main+35>: mov %eax,%ecx
(gdb)
0x00001f09 21 bar (&&nonlocal_lab);
1: x/i $pc 0x1f09 <main+37>: call 0x1ebd <bar>
(gdb)
bar (func=0x1f18) at
/sw/src/fink.build/gcc48-4.8.0-1000/gcc-4.8-20130120/gcc/testsuite/gcc.c-torture/execute/pr51447.c:17
17 {
1: x/i $pc 0x1ebd <bar>: push %ebp
(gdb)
0x00001ebe 17 {
1: x/i $pc 0x1ebe <bar+1>: mov %esp,%ebp
(gdb)
0x00001ec0 17 {
1: x/i $pc 0x1ec0 <bar+3>: push %ebx
(gdb)
0x00001ec1 17 {
1: x/i $pc 0x1ec1 <bar+4>: call 0x1f3e <__x86.get_pc_thunk.bx>
(gdb)
0x00001f3e in __x86.get_pc_thunk.bx ()
1: x/i $pc 0x1f3e <__x86.get_pc_thunk.bx>: mov (%esp),%ebx
(gdb)
0x00001f41 in __x86.get_pc_thunk.bx ()
1: x/i $pc 0x1f41 <__x86.get_pc_thunk.bx+3>: ret
(gdb)
0x00001ec6 in bar (func=0x1f18) at
/sw/src/fink.build/gcc48-4.8.0-1000/gcc-4.8-20130120/gcc/testsuite/gcc.c-torture/execute/pr51447.c:17
17 {
1: x/i $pc 0x1ec6 <bar+9>: mov %ecx,%edx
(gdb)
Breakpoint 2, bar (func=0x1f18) at
/sw/src/fink.build/gcc48-4.8.0-1000/gcc-4.8-20130120/gcc/testsuite/gcc.c-torture/execute/pr51447.c:18
18 ptr = func;
1: x/i $pc 0x1ec8 <bar+11>: lea 0x142(%ebx),%eax
(gdb)
0x00001ece 18 ptr = func;
1: x/i $pc 0x1ece <bar+17>: mov (%eax),%eax
(gdb)
0x00001ed0 18 ptr = func;
1: x/i $pc 0x1ed0 <bar+19>: mov 0x8(%ebp),%ecx
(gdb)
0x00001ed3 18 ptr = func;
1: x/i $pc 0x1ed3 <bar+22>: mov %ecx,(%eax)
(gdb)
19 goto nonlocal_lab;
1: x/i $pc 0x1ed5 <bar+24>: mov %edx,%eax
(gdb)
0x00001ed7 19 goto nonlocal_lab;
1: x/i $pc 0x1ed7 <bar+26>: lea 0x4f(%ebx),%edx
(gdb)
0x00001edd 19 goto nonlocal_lab;
1: x/i $pc 0x1edd <bar+32>: mov (%eax),%ebp
(gdb)
0x00001edf in bar (func=0xbffff8e0) at
/sw/src/fink.build/gcc48-4.8.0-1000/gcc-4.8-20130120/gcc/testsuite/gcc.c-torture/execute/pr51447.c:19
19 goto nonlocal_lab;
1: x/i $pc 0x1edf <bar+34>: mov 0x4(%eax),%esp
(gdb)
0x00001ee2 19 goto nonlocal_lab;
1: x/i $pc 0x1ee2 <bar+37>: jmp *%edx
(gdb)
0x00001f15 in main () at
/sw/src/fink.build/gcc48-4.8.0-1000/gcc-4.8-20130120/gcc/testsuite/gcc.c-torture/execute/pr51447.c:22
22 return 1;
1: x/i $pc 0x1f15 <main+49>: lea 0x18(%ebp),%ebp
(gdb)
main () at
/sw/src/fink.build/gcc48-4.8.0-1000/gcc-4.8-20130120/gcc/testsuite/gcc.c-torture/execute/pr51447.c:24
24 if (ptr != &&nonlocal_lab)
1: x/i $pc 0x1f18 <main+52>: lea 0x116(%ebx),%eax
(gdb)
0x00001f1e 24 if (ptr != &&nonlocal_lab)
1: x/i $pc 0x1f1e <main+58>: mov (%eax),%eax
(gdb)
0x00001f20 24 if (ptr != &&nonlocal_lab)
1: x/i $pc 0x1f20 <main+60>: mov (%eax),%edx
(gdb)
Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x0104c700
0x00001f20 in main () at
/sw/src/fink.build/gcc48-4.8.0-1000/gcc-4.8-20130120/gcc/testsuite/gcc.c-torture/execute/pr51447.c:24
24 if (ptr != &&nonlocal_lab)