[Bug tree-optimization/54916] New: [4.8 Regression] wrong code with -O2 -funroll-loops -fno-rerun-cse-after-loop
zsojka at seznam dot cz
gcc-bugzilla@gcc.gnu.org
Fri Oct 12 19:19:00 GMT 2012
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54916
Bug #: 54916
Summary: [4.8 Regression] wrong code with -O2 -funroll-loops
-fno-rerun-cse-after-loop
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: zsojka@seznam.cz
Created attachment 28435
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28435
testcase (gcc.dg/pr39794.c)
Output:
$ gcc -O2 -funroll-loops -fno-rerun-cse-after-loop pr39794.i
$ ./a.out
Aborted
(gdb) p a
$1 = {0, 1, 4, 2, 10, 12, 24, 44, 36, 136, 160, 344, 592, 1008, 1872, 1600}
(gdb) p ref
$2 = {0, 1, 4, 2, 10, 12, 24, 44, 72, 136, 232, 416, 736, 1296, 2304, 2032}
Binary is fine when compiled without -fno-rerun-cse-after-loop
Tested revisions:
r192388 - fail
r191586 - fail
4.7 r191640 - OK
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