[Bug rtl-optimization/28481] New: regression from 3.x: 4.1.1 uses memory where it can use registers

[vda dot linux at googlemail dot com]

The attached test program uses 5 local variables and this fits into i386
available registers. gcc 3.4.3 manages to do it with -O3.

gcc-4.1.1 -O2 and -O3 are identical and both are worse than gcc-3.4.3 -O3:

# wc -l *.s
  1498 serpent343-O2.s
  1252 serpent343-O3.s <- gcc 3.4.3 is smaller!
  1313 serpent411-O2.s
  1313 serpent411-O3.s

gcc-4.1.1 -Os is better than -O3, but still a tiny bit worse than gcc-3.4.3:

# wc -l serpent343-O3.s serpent411-Os.s
 1252 serpent343-O3.s
 1275 serpent411-Os.s

# size serpent343-O3.o serpent411-Os.o
   3262       0       0    3262     cbe serpent343-O3.o
   3347       0       0    3347     d13 serpent411-Os.o

Additional ingo is in the testcase itself.

(btw does it make sense to include this into testsuite?)


-- 
           Summary: regression from 3.x: 4.1.1 uses memory where it can use
                    registers
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: vda dot linux at googlemail dot com
 GCC build triplet: i386-pc-linux-gnu
  GCC host triplet: i386-pc-linux-gnu
GCC target triplet: i386-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28481