[Bug tree-optimization/27299] [4.1 Regression] vectorizer generates aligned accesses to unaligned memory

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2006-04-25 11:49 -------
Confirmed.  We generate

0x08048475 <main+193>:  movdqu (%edx),%xmm0
0x08048479 <main+197>:  movdqa %xmm0,(%eax)

but both %edx and %eax are unaligned:

eax            0x804a021        134520865
ecx            0x0      0
edx            0x804a009        134520841

4.0.3 works, because nothing is vectorized there.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |wrong-code
      Known to fail|                            |4.1.0
      Known to work|                            |4.0.3
   Last reconfirmed|0000-00-00 00:00:00         |2006-04-25 11:49:33
               date|                            |
            Summary|gcc 4.1 produces bad code - |[4.1 Regression] vectorizer
                   |ftree-vectorize option      |generates aligned accesses
                   |                            |to unaligned memory


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27299