[Bug optimization/11707] constants not propagated in unrolled loop iterations with a conditional

["rguenth at tat dot physik dot uni-tuebingen dot de" <gcc-bugzilla at gcc dot gnu dot org>]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11707


rguenth at tat dot physik dot uni-tuebingen dot de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|enhancement                 |normal


------- Additional Comments From rguenth at tat dot physik dot uni-tuebingen dot de  2003-07-29 14:07 -------
This is actually a regression from 2.95.3 (-O2 -funroll-loops):

gcc2_compiled.:
.text
        .align 16
.globl foo2
        .type    foo2,@function
foo2:
        pushl %ebp
        movl %esp,%ebp
        movl $1,%eax
        movl %ebp,%esp
        popl %ebp
        ret

and a regression from 3.3 to which this is a regression from 2.92.3:

        .text
        .p2align 4,,15
.globl foo2
        .type   foo2, @function
foo2:
        pushl   %ebp
        movl    $1, %eax        #  a
        movl    %esp, %ebp
        popl    %ebp
        imull   %eax, %eax      #  a,  a
        ret

and of course worst for gcc3.4:

        .text
        .p2align 4,,15
.globl foo2
        .type   foo2, @function
foo2:
        pushl   %ebp    #
        movl    $5, %eax        #, n
        shrl    %eax    # tmp62 
        testl   %eax, %eax      # n
        movl    %esp, %ebp      #, 
        movl    $1, %edx        #, a
        je      .L11    #,      
        imull   %edx, %edx      # a, a
.L11:
        shrl    %eax    # n     
        testl   %eax, %eax      # n
        je      .L4     #,      
        imull   %edx, %edx      # a, a
.L4:
        popl    %ebp    #
        movl    %edx, %eax      # a, <result>
        ret

With gcc3.4 and -fold-unroll-loops we get back to 2.95.3 code:

       .text
        .p2align 4,,15
.globl foo2
        .type   foo2, @function
foo2:
        pushl   %ebp    #
        movl    $1, %eax        #, <result>
        movl    %esp, %ebp      #,
        popl    %ebp    #
        ret

So can this be targeted at 3.3 and marked as regression? Thanks.