http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56199
Bug #: 56199
Summary: strcpy/strcat builtins generates suboptimal code.
Classification: Unclassified
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: nel...@seznam.cz
Current strcpy/strcat generates code in form
movabsq $7954893459765158241, %r11
movq %r11,(%rax)
...
Which is slower than copying string from memory using
movq (%rdx),%r11
movq %r11,(%rax)
...
Attached benchmark is 50% faster on sandy bridge for 70 byte string.
Note that icc also translates strcpy into this form(but not strcat for some
reason.)
