[Bug other/56631] New: duplicated sse code in switch

[neleai at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56631



             Bug #: 56631

           Summary: duplicated sse code in switch

    Classification: Unclassified

           Product: gcc

           Version: unknown

            Status: UNCONFIRMED

          Severity: normal

          Priority: P3

         Component: other

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: nel...@seznam.cz





Consider attached testcase. When compiled with -Os,-O2,-O3 it duplicates

zeroing xmm1 register across all branches. Moving zeroing before braches will

save space.



Relevant assembly at -Os is



  jmp *.L19(,%rax,8)

  .section  .rodata

  .align 8

  .align 4

.L19:

  .quad .L21

  .quad .L4

  .quad .L5

snip 



.L21:

  xorps %xmm1, %xmm1

.L38:

  movaps  %xmm0, %xmm2

  pcmpeqb %xmm1, %xmm2

  pmovmskb  %xmm2, %eax

  testl %eax, %eax

  jne .L1

.L2:

  movdqu  %xmm0, (%rdi)

  addq  $64, %rdi

  movups  64(%rsi), %xmm0

  addq  $64, %rsi

  jmp .L38

.L4:

  xorps %xmm1, %xmm1

  incq  %rdi

.L23:

snip

.L5:

  xorps %xmm1, %xmm1

  addq  $2, %rdi