[Bug c/28545] New: Wrong code for hoisted multiplication

[ben at decadentplace dot org dot uk]

I have some code that calls
    memset(p, cr+1, cr*cr);
inside a loop.  (Will attach this later.)

gcc 4.1.2 (snapshot from 20060715) appears to attempt to calculate cr*cr
outside the loop and then load it when needed. However, the generated code uses
the wrong register for one the multiplicands:

        movl    %edi, %ecx     /* edi contains cr */
        xorl    %eax, %eax
        imull   %ebx, %ecx     /* ebx contains another variable */
        leal    1(%edi), %ebx


-- 
           Summary: Wrong code for hoisted multiplication
           Product: gcc
           Version: 4.1.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ben at decadentplace dot org dot uk
 GCC build triplet: i486-linux-gnu
  GCC host triplet: i486-linux-gnu
GCC target triplet: i486-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28545