mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-02-23 03:39:09 +08:00
Code Issues Packages Projects Releases Wiki Activity

* regrename.c (copy_value): Don't record high part copies.

Browse Source 
From-SVN: r55493
This commit is contained in:
J"orn Rennecke 2002-07-16 20:13:35 +00:00 committed by Joern Rennecke
parent 99b823ca2a
commit dbf65c2f4e
2 changed files with 24 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
gcc/ChangeLog
View File

@ -1,3 +1,7 @@
Tue Jul 16 19:32:58 2002 J"orn Rennecke <joern.rennecke@superh.com>
* regrename.c (copy_value): Don't record high part copies.
2002-07-16 Steve Ellcey <sje@cup.hp.com>
* gcc/config/pa/long_double.h (FIXUNS_TRUNCTFDI2_LIBCALL): New define.

20
gcc/regrename.c
View File

@ -1268,6 +1268,26 @@ copy_value (dest, src, vd)
if (vd->e[sr].mode == VOIDmode)
set_value_regno (sr, vd->e[dr].mode, vd);
/* If we are narrowing the the input to a smaller number of hard regs,
and it is in big endian, we are really extracting a high part.
Since we generally associate a low part of a value with the value itself,
we must not do the same for the high part.
Note we can still get low parts for the same mode combination through
a two-step copy involving differently sized hard regs.
Assume hard regs fr* are 32 bits bits each, while r* are 64 bits each:
(set (reg:DI r0) (reg:DI fr0))
(set (reg:SI fr2) (reg:SI r0))
loads the low part of (reg:DI fr0) - i.e. fr1 - into fr2, while:
(set (reg:SI fr2) (reg:SI fr0))
loads the high part of (reg:DI fr0) into fr2.
We can't properly represent the latter case in our tables, so don't
record anything then. */
else if (sn < (unsigned int) HARD_REGNO_NREGS (sr, vd->e[sr].mode)
&& (GET_MODE_SIZE (vd->e[sr].mode) > UNITS_PER_WORD
? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN))
return;
/* If SRC had been assigned a mode narrower than the copy, we can't
link DEST into the chain, because not all of the pieces of the
copy came from oldest_regno. */