https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68729
John David Anglin <danglin at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |law at gcc dot gnu.org
--- Comment #1 from John David Anglin <danglin at gcc dot gnu.org> ---
The problem occurs trying to do an HImode reload to a floating point register.
pa_emit_move_sequence is called as follows:
(gdb) p debug_rtx (operands[1])
(subreg:SI (reg:HI 3488 [ *_720 ]) 0)
$26 = void
(gdb) p debug_rtx (operands[0])
(reg:SI 68 %fr22)
$27 = void
(gdb) p debug_rtx (operands[1])
(subreg:SI (reg:HI 3488 [ *_720 ]) 0)
$28 = void
(gdb) p mode
$29 = HImode
(gdb) p debug_rtx (scratch_reg)
(reg:HI 20 %r20)
operand1, which is operand[1], is altered here:
else if (scratch_reg
&& reload_in_progress && GET_CODE (operand1) == SUBREG
&& GET_CODE (SUBREG_REG (operand1)) == REG
&& REGNO (SUBREG_REG (operand1)) >= FIRST_PSEUDO_REGISTER)
{
/* We must not alter SUBREG_BYTE (operand0) since that would confuse
the code which tracks sets/uses for delete_output_reload. */
rtx temp = gen_rtx_SUBREG (GET_MODE (operand1),
reg_equiv_mem (REGNO (SUBREG_REG (operand1))),
SUBREG_BYTE (operand1));
operand1 = alter_subreg (&temp, true);
}
yielding
(gdb) p debug_rtx (operand1)
(mem/c:SI (plus:SI (reg/f:SI 30 %r30)
(const_int -256 [0xffffffffffffff00])) [38 %sfp+64 S4 A16])
$31 = void
Have to wonder if the above is truly equivalent given the high portion
might be nonzero and we can only load 32 and 64-bit floating point values
from memory.
The subsequent code that normally would handle reloads to a floating
/* Handle secondary reloads for loads/stores of FP registers from
REG+D addresses where D does not fit in 5 or 14 bits, including
(subreg (mem (addr))) cases. */
if (scratch_reg
&& fp_reg_operand (operand0, mode)
&& (MEM_P (operand1)
|| (GET_CODE (operand1) == SUBREG
&& MEM_P (XEXP (operand1, 0))))
&& !floating_point_store_memory_operand (operand1, mode))
{
is not invoked since we operand0 is SImode and mode is HImode.
Jeff, do you have a comment on how this should be handled?
