[Bug target/78794] New: [7 Regression] We noticed ~9% regression in 32-bit mode for 462.libquntum on Avoton after r243202

["ysrumyan at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78794

            Bug ID: 78794
           Summary: [7 Regression] We noticed ~9% regression in 32-bit
                    mode for 462.libquntum on Avoton after r243202
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ysrumyan at gmail dot com
  Target Milestone: ---

STV phase does not recognize some patterns after this revision, regression can
be reproduced with attached simple test-case. Note that before this revision
the following code has been produced for loop body:
.L4:
        movq    (%eax), %xmm1
        movdqa  %xmm1, %xmm4
        pand    %xmm2, %xmm4
        movdqa  %xmm4, %xmm0
        pxor    %xmm2, %xmm0
        punpcklqdq      %xmm0, %xmm0
        ptest   %xmm0, %xmm0
        jne     .L3
        pxor    %xmm3, %xmm1
        movq    %xmm1, (%eax)
.L3:
        addl    $12, %eax
        cmpl    %edx, %eax
        jne     .L4

but after we see
.L4:
        movl    4(%eax), %edi
        movl    (%eax), %esi
        movl    %edi, %ebx
        movl    %esi, %ecx
        notl    %ebx
        andl    4(%esp), %ebx
        notl    %ecx
        andl    (%esp), %ecx
        movl    %ebx, %ebp
        orl     %ecx, %ebp
        jne     .L3
        xorl    8(%esp), %esi
        xorl    12(%esp), %edi
        movl    %esi, (%eax)
        movl    %edi, 4(%eax)
.L3:
        addl    $12, %eax
        cmpl    %edx, %eax
        jne     .L4