------- Comment #14 from dirtyepic at gentoo dot org 2007-09-23 05:59 ------- Created an attachment (id=14246) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14246&action=view) inftrees.c
this is the testcase from bug #25413. with -O2 -msse2 -ftree-vectorize, i get this in gcc-4.2.0: inftrees.o: file format elf32-i386 Disassembly of section .text: 00000000 <inflate_table>: 0: 55 push %ebp 1: 89 e5 mov %esp,%ebp 3: 53 push %ebx 4: 83 ec 24 sub $0x24,%esp 7: 8b 5d 0c mov 0xc(%ebp),%ebx a: 8b 4d 10 mov 0x10(%ebp),%ecx d: 66 0f ef c0 pxor %xmm0,%xmm0 11: 66 0f 7f 45 d8 movdqa %xmm0,-0x28(%ebp) 16: 66 0f 7f 45 e8 movdqa %xmm0,-0x18(%ebp) 1b: 85 c9 test %ecx,%ecx 1d: 74 16 je 35 <inflate_table+0x35> 1f: ba 00 00 00 00 mov $0x0,%edx 24: 0f b7 04 53 movzwl (%ebx,%edx,2),%eax 28: 66 83 44 45 d8 01 addw $0x1,-0x28(%ebp,%eax,2) 2e: 83 c2 01 add $0x1,%edx 31: 39 ca cmp %ecx,%edx 33: 75 ef jne 24 <inflate_table+0x24> 35: b8 00 00 00 00 mov $0x0,%eax 3a: 8d 55 d8 lea -0x28(%ebp),%edx 3d: 66 83 7c 42 1e 00 cmpw $0x0,0x1e(%edx,%eax,2) 43: 75 08 jne 4d <inflate_table+0x4d> 45: 83 e8 01 sub $0x1,%eax 48: 83 f8 f1 cmp $0xfffffff1,%eax 4b: 75 f0 jne 3d <inflate_table+0x3d> 4d: 83 c4 24 add $0x24,%esp 50: 5b pop %ebx 51: 5d pop %ebp 52: c3 ret forcing alignment as in comment #5 results in: inftrees-align.o: file format elf32-i386 Disassembly of section .text: 00000000 <inflate_table>: 0: 55 push %ebp 1: 89 e5 mov %esp,%ebp 3: 53 push %ebx 4: 83 ec 24 sub $0x24,%esp 7: 8b 5d 0c mov 0xc(%ebp),%ebx a: 8b 4d 10 mov 0x10(%ebp),%ecx d: b8 01 00 00 00 mov $0x1,%eax 12: 8d 55 d8 lea -0x28(%ebp),%edx 15: 66 c7 44 42 fe 00 00 movw $0x0,-0x2(%edx,%eax,2) 1c: 83 c0 01 add $0x1,%eax 1f: 83 f8 11 cmp $0x11,%eax 22: 75 f1 jne 15 <inflate_table+0x15> 24: 85 c9 test %ecx,%ecx 26: 74 16 je 3e <inflate_table+0x3e> 28: ba 00 00 00 00 mov $0x0,%edx 2d: 0f b7 04 53 movzwl (%ebx,%edx,2),%eax 31: 66 83 44 45 d8 01 addw $0x1,-0x28(%ebp,%eax,2) 37: 83 c2 01 add $0x1,%edx 3a: 39 ca cmp %ecx,%edx 3c: 75 ef jne 2d <inflate_table+0x2d> 3e: b8 00 00 00 00 mov $0x0,%eax 43: 8d 55 d8 lea -0x28(%ebp),%edx 46: 66 83 7c 42 1e 00 cmpw $0x0,0x1e(%edx,%eax,2) 4c: 75 08 jne 56 <inflate_table+0x56> 4e: 83 e8 01 sub $0x1,%eax 51: 83 f8 f1 cmp $0xfffffff1,%eax 54: 75 f0 jne 46 <inflate_table+0x46> 56: 83 c4 24 add $0x24,%esp 59: 5b pop %ebx 5a: 5d pop %ebp 5b: c3 ret there's a gdb log for the segfault in firefox @ http://gcc.gnu.org/bugzilla/attachment.cgi?id=13966 i'll try to find something a little smaller than mozilla that can demonstrate this problem since i still suck at testcases. FWIW, i've been running GCC-4.2 svn with the patch at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25413#c17 for a couple months now and have built a sizable chunk of our package repository with -ftree-vectorize enabled several times over and have yet to run into any trouble whatsoever. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32893
