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arm.c (arm_legitimize_address): Split absolute addresses to alow matching ARM pre-indexed addressing mode.

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* config/arm/arm.c (arm_legitimize_address): Split absolute addresses
to alow matching ARM pre-indexed addressing mode.
(arm_override_options): Remove now irrelevant comment.

From-SVN: r103742
This commit is contained in:
Nicolas Pitre 2005-09-01 19:01:20 +00:00 • committed by Nicolas Pitre
parent d442d7d9dd
commit 868057591b
2 changed files with 34 additions and 4 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2005-09-01 Nicolas Pitre <nico@cam.org>
* config/arm/arm.c (arm_legitimize_address): Split absolute addresses
to alow matching ARM pre-indexed addressing mode.
(arm_override_options): Remove now irrelevant comment.
2005-09-01 Phil Edwards <phil@codesourcery.com>
* config.gcc (i*86-wrs-vxworks): Update. Split out vxworksae target.

32
gcc/config/arm/arm.c
View file

@ -1234,10 +1234,6 @@ arm_override_options (void)
if (optimize_size)
{
/* There's some dispute as to whether this should be 1 or 2. However,
experiments seem to show that in pathological cases a setting of
1 degrades less severely than a setting of 2. This could change if
other parts of the compiler change their behavior. */
arm_constant_limit = 1;
/* If optimizing for size, bump the number of instructions that we
@ -3759,6 +3755,34 @@ arm_legitimize_address (rtx x, rtx orig_x, enum machine_mode mode)
x = gen_rtx_MINUS (SImode, xop0, xop1);
}
/* Make sure to take full advantage of the pre-indexed addressing mode
with absolute addresses which often allows for the base register to
be factorized for multiple adjacent memory references, and it might
even allows for the mini pool to be avoided entirely. */
else if (GET_CODE (x) == CONST_INT && optimize > 0)
{
unsigned int bits;
HOST_WIDE_INT mask, base, index;
rtx base_reg;
/* ldr and ldrb can use a 12 bit index, ldrsb and the rest can only
use a 8 bit index. So let's use a 12 bit index for SImode only and
hope that arm_gen_constant will enable ldrb to use more bits. */
bits = (mode == SImode) ? 12 : 8;
mask = (1 << bits) - 1;
base = INTVAL (x) & ~mask;
index = INTVAL (x) & mask;
if (bit_count (base) > (32 - bits)/2)
{
/* It'll most probably be more efficient to generate the base
with more bits set and use a negative index instead. */
base |= mask;
index -= mask;
}
base_reg = force_reg (SImode, GEN_INT (base));
x = gen_rtx_PLUS (SImode, base_reg, GEN_INT (index));
}
if (flag_pic)
{
/* We need to find and carefully transform any SYMBOL and LABEL