[Bug middle-end/82325] worse code generated compared to clang when using a constexpr array

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82325

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |middle-end

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note clang 15+ no longer unrolls the loop and even produces really bad code for
the loop now:
.LBB0_7:                                #   in Loop: Header=BB0_1 Depth=1
        addq    $2, %rdx
.LBB0_1:                                # =>This Inner Loop Header: Depth=1
        movzwl  -4(%rax,%rdx,4), %esi
        cmpl    %edi, %esi
        jg      .LBB0_3
# %bb.2:                                #   in Loop: Header=BB0_1 Depth=1
        movzbl  -2(%rax,%rdx,4), %ecx
        movl    $1, %r8d
        shll    %cl, %r8d
        addl    %esi, %r8d
        cmpl    %edi, %r8d
        jg      .LBB0_8
.LBB0_3:                                #   in Loop: Header=BB0_1 Depth=1
        cmpq    $29, %rdx
        je      .LBB0_4
# %bb.5:                                #   in Loop: Header=BB0_1 Depth=1
        movzwl  (%rax,%rdx,4), %esi
        cmpl    %edi, %esi
        jg      .LBB0_7
# %bb.6:                                #   in Loop: Header=BB0_1 Depth=1
        movzbl  2(%rax,%rdx,4), %ecx
        movl    $1, %r8d
        shll    %cl, %r8d
        addl    %esi, %r8d
        cmpl    %edi, %r8d
        jle     .LBB0_7