[Bug optimization/14552] New: compiled trivial vector intrinsic code contains nearly twice as many instructions as needed

[michaelni at gmx dot at]

See attached source, gcc  -O3 -mtune=pentium3 -march=pentium3 -S 
generates: 
test: 
        movq    w, %mm1 
        pushl   %ebp 
        movl    %esp, %ebp 
        popl    %ebp 
        psllw   $1, %mm1 
        movq    %mm1, w 
        movq    w, %mm0 
        movq    %mm0, dw 
        ret 
 
human generates: 
movq w, %mm1 
paddw %mm1,%mm1 
movq %mm1, w 
movq %mm1,dw 
ret

-- 
           Summary: compiled trivial vector intrinsic code contains nearly
                    twice as many instructions as needed
           Product: gcc
           Version: 3.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: michaelni at gmx dot at
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: pentium3-debian-linux
GCC target triplet: pentium3-debian-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14552