[Bug target/18562] SSE constant vector initialization produces dead constant values on stack

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2005-01-12 
09:37 -------
AMD64 has this at -O2: 
 
Test case 1: 
main: 
.LFB499: 
        subq    $24, %rsp 
.LCFI0: 
        movl    $.LC1, %edi 
        movl    $4, %eax 
        movaps  .LC0(%rip), %xmm0 
        movups  %xmm0, (%rsp) 
        cvtss2sd        12(%rsp), %xmm3 
        cvtss2sd        8(%rsp), %xmm2 
        cvtss2sd        4(%rsp), %xmm1 
        cvtss2sd        (%rsp), %xmm0 
        call    printf 
        xorl    %eax, %eax 
        addq    $24, %rsp 
        ret 
.LFE499: 
 
 
Test case 2: 
main: 
.LFB499: 
        subq    $40, %rsp 
.LCFI0: 
        movl    $.LC4, %edi 
        movl    $4, %eax 
        movl    $0x3fa66666, 16(%rsp) 
        movl    $0x3fb33333, 20(%rsp) 
        movl    $0x3fc00000, 24(%rsp) 
        movl    $0x3fcccccd, 28(%rsp) 
        movups  16(%rsp), %xmm0 
        movups  %xmm0, (%rsp) 
        cvtss2sd        12(%rsp), %xmm3 
        cvtss2sd        8(%rsp), %xmm2 
        cvtss2sd        4(%rsp), %xmm1 
        cvtss2sd        (%rsp), %xmm0 
        call    printf 
        xorl    %eax, %eax 
        addq    $40, %rsp 
        ret 
 
 
 
With -m32 -march=pentium4 -mtune=prescott I get this: 
 
Test case 1: 
main: 
        pushl   %ebp 
        movl    %esp, %ebp 
        subl    $56, %esp 
        andl    $-16, %esp 
        subl    $16, %esp 
        movaps  .LC0, %xmm0 
        movups  %xmm0, -16(%ebp) 
        flds    -4(%ebp) 
        fstpl   28(%esp) 
        flds    -8(%ebp) 
        fstpl   20(%esp) 
        flds    -12(%ebp) 
        fstpl   12(%esp) 
        flds    -16(%ebp) 
        fstpl   4(%esp) 
        movl    $.LC1, (%esp) 
        call    printf 
        xorl    %eax, %eax 
        leave 
        ret 
 
Test case 2 (which is basically the same as Uros' code): 
main: 
        pushl   %ebp 
        movl    %esp, %ebp 
        subl    $72, %esp 
        andl    $-16, %esp 
        subl    $16, %esp 
        movl    $0x3fa66666, -16(%ebp) 
        movl    $0x3fb33333, -12(%ebp) 
        movl    $0x3fc00000, -8(%ebp) 
        movl    $0x3fcccccd, -4(%ebp) 
        movups  -16(%ebp), %xmm0 
        movups  %xmm0, -32(%ebp) 
        flds    -20(%ebp) 
        fstpl   28(%esp) 
        flds    -24(%ebp) 
        fstpl   20(%esp) 
        flds    -28(%ebp) 
        fstpl   12(%esp) 
        flds    -32(%ebp) 
        fstpl   4(%esp) 
        movl    $.LC4, (%esp) 
        call    printf 
        xorl    %eax, %eax 
        leave 
        ret 
 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18562