[Bug target/49600] New: Bad int->float split in i386.md

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49600

           Summary: Bad int->float split in i386.md
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: hjl.tools@gmail.com
                CC: ubizjak@gmail.com


There is

(define_split
  [(set (match_operand:MODEF 0 "register_operand" "")
        (float:MODEF (match_operand:SI 1 "register_operand" "")))]
  "TARGET_SSE2 && TARGET_SSE_MATH
   && TARGET_USE_VECTOR_CONVERTS && optimize_function_for_speed_p (cfun)
   && reload_completed
   && (SSE_REG_P (operands[0])
       || (GET_CODE (operands[0]) == SUBREG
           && SSE_REG_P (operands[0])))"
  [(const_int 0)]
{
  rtx op1 = operands[1];

  operands[3] = simplify_gen_subreg (<ssevecmode>mode, operands[0],
                                     <MODE>mode, 0);
  if (GET_CODE (op1) == SUBREG)
    op1 = SUBREG_REG (op1);

  if (GENERAL_REG_P (op1) && TARGET_INTER_UNIT_MOVES)
    {
      operands[4] = simplify_gen_subreg (V4SImode, operands[0], <MODE>mode, 0);
      emit_insn (gen_sse2_loadld (operands[4],
                                  CONST0_RTX (V4SImode), operands[1]));
    }
  /* We can ignore possible trapping value in the
     high part of SSE register for non-trapping math. */
  else if (SSE_REG_P (op1) && !flag_trapping_math)
    operands[4] = simplify_gen_subreg (V4SImode, operands[1], SImode, 0);
  else    
    gcc_unreachable ();
  emit_insn
    (gen_sse2_cvtdq2p<ssemodefsuffix> (operands[3], operands[4]));
  DONE;   
})

When TARGET_USE_VECTOR_CONVERTS is true, TARGET_INTER_UNIT_MOVES
is false and GENERAL_REG_P (op1) is true. we will get gcc_unreachable.