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s390.c (legitimize_address): Optimize loading of large displacements.

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* config/s390/s390.c (legitimize_address): Optimize loading
	of large displacements.

From-SVN: r56345
This commit is contained in:
Ulrich Weigand 2002-08-15 09:55:31 +00:00 committed by Ulrich Weigand
parent 6848fc973f
commit 61f02ff548
2 changed files with 30 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2002-08-15 Ulrich Weigand <uweigand@de.ibm.com>
* config/s390/s390.c (legitimize_address): Optimize loading
of large displacements.
2002-08-14 Douglas B Rupp <rupp@gnat.com>
* config/alpha/alpha-protos.h: Update.

25
gcc/config/s390/s390.c
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@ -2084,6 +2084,31 @@ legitimize_address (x, oldx, mode)
x = eliminate_constant_term (x, &constant_term);
/* Optimize loading of large displacements by splitting them
into the multiple of 4K and the rest; this allows the
former to be CSE'd if possible.
Don't do this if the displacement is added to a register
pointing into the stack frame, as the offsets will
change later anyway. */
if (GET_CODE (constant_term) == CONST_INT
&& (INTVAL (constant_term) < 0
|| INTVAL (constant_term) >= 4096)
&& !(REG_P (x) && REGNO_PTR_FRAME_P (REGNO (x))))
{
HOST_WIDE_INT lower = INTVAL (constant_term) & 0xfff;
HOST_WIDE_INT upper = INTVAL (constant_term) ^ lower;
rtx temp = gen_reg_rtx (Pmode);
rtx val = force_operand (GEN_INT (upper), temp);
if (val != temp)
emit_move_insn (temp, val);
x = gen_rtx_PLUS (Pmode, x, temp);
constant_term = GEN_INT (lower);
}
if (GET_CODE (x) == PLUS)
{
if (GET_CODE (XEXP (x, 0)) == REG)