mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-04-05 08:00:26 +08:00
Code Issues Packages Projects Releases Wiki Activity

pa.c (hppa_legitimize_address): Don't lose for x[n-const] when n-const will not be shifted.

Browse Source 
* pa.c (hppa_legitimize_address): Don't lose for x[n-const]
        when n-const will not be shifted.  Don't pessimize code for
        x[n-const] when const is small.

From-SVN: r11579
This commit is contained in:
Jeff Law 1996-03-20 11:15:13 -07:00
parent 66795cc713
commit c2827c50df
1 changed files with 19 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
gcc/config/pa/pa.c
View File

@ -807,24 +807,22 @@ hppa_legitimize_address (x, oldx, mode)
}
/* Uh-oh. We might have an address for x[n-100000]. This needs
special handling.
special handling to avoid creating an indexed memory address
with x-100000 as the base.
If the constant part is small enough, then it's still safe because
there is a guard page at the beginning and end of the data segment.
This is common enough that we want to try and rearrange the terms
so that we can use indexing for these addresses too. Again, only
Scaled references are common enough that we want to try and rearrange the
terms so that we can use indexing for these addresses too. Only
do the optimization for floatint point modes. */
if (GET_CODE (x) == PLUS && GET_CODE (XEXP (x, 0)) == MULT
&& GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
&& shadd_constant_p (INTVAL (XEXP (XEXP (x, 0), 1))))
if (GET_CODE (x) == PLUS
&& symbolic_expression_p (XEXP (x, 1)))
{
/* Ugly. We modify things here so that the address offset specified
by the index expression is computed first, then added to x to form
the entire address.
For 2.5, it might be profitable to set things up so that we
compute the raw (unscaled) index first, then use scaled indexing
to access memory, or better yet have the MI parts of the compiler
handle this. */
the entire address. */
rtx regx1, regx2, regy1, regy2, y;
@ -860,6 +858,15 @@ hppa_legitimize_address (x, oldx, mode)
XEXP (XEXP (x, 0), 1)),
force_reg (Pmode, XEXP (y, 0))));
}
else if (GET_CODE (XEXP (y, 1)) == CONST_INT
&& INTVAL (XEXP (y, 1)) >= -4096
&& INTVAL (XEXP (y, 1)) <= 4095)
{
/* This is safe because of the guard page at the
beginning and end of the data space. Just
return the original address. */
return orig;
}
else
{
/* Doesn't look like one we can optimize. */