OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

expr.c (undefined_operand_subword_p): New. 

* expr.c (undefined_operand_subword_p): New.
	(emit_move_multi_word): Do not generate move from undefined bits
	of a paradoxical subreg.

From-SVN: r114021
This commit is contained in:
Joseph Myers 2006-05-23 19:54:37 +01:00 committed by Joseph Myers
parent e5d7a5205e
commit 550ab0c644
2 changed files with 46 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
gcc/ChangeLog
View File

@ -1,3 +1,9 @@
2006-05-23 Joseph Myers <joseph@codesourcery.com>
* expr.c (undefined_operand_subword_p): New.
(emit_move_multi_word): Do not generate move from undefined bits
of a paradoxical subreg.
2006-05-23 Richard Sandiford <richard@codesourcery.com>
PR rtl-optimization/27736

41
gcc/expr.c
View File

@ -3096,6 +3096,38 @@ emit_move_ccmode (enum machine_mode mode, rtx x, rtx y)
return ret;
}
/* Return true if word I of OP lies entirely in the
undefined bits of a paradoxical subreg. */
static bool
undefined_operand_subword_p (rtx op, int i)
{
enum machine_mode innermode, innermostmode;
int offset;
if (GET_CODE (op) != SUBREG)
return false;
innermode = GET_MODE (op);
innermostmode = GET_MODE (SUBREG_REG (op));
offset = i * UNITS_PER_WORD + SUBREG_BYTE (op);
/* The SUBREG_BYTE represents offset, as if the value were stored in
memory, except for a paradoxical subreg where we define
SUBREG_BYTE to be 0; undo this exception as in
simplify_subreg. */
if (SUBREG_BYTE (op) == 0
&& GET_MODE_SIZE (innermostmode) < GET_MODE_SIZE (innermode))
{
int difference = (GET_MODE_SIZE (innermostmode) - GET_MODE_SIZE (innermode));
if (WORDS_BIG_ENDIAN)
offset += (difference / UNITS_PER_WORD) * UNITS_PER_WORD;
if (BYTES_BIG_ENDIAN)
offset += difference % UNITS_PER_WORD;
}
if (offset >= GET_MODE_SIZE (innermostmode)
|| offset <= -GET_MODE_SIZE (word_mode))
return true;
return false;
}
/* A subroutine of emit_move_insn_1. Generate a move from Y into X.
MODE is any multi-word or full-word mode that lacks a move_insn
pattern. Note that you will get better code if you define such
@ -3133,7 +3165,14 @@ emit_move_multi_word (enum machine_mode mode, rtx x, rtx y)
i++)
{
rtx xpart = operand_subword (x, i, 1, mode);
rtx ypart = operand_subword (y, i, 1, mode);
rtx ypart;
/* Do not generate code for a move if it would come entirely
from the undefined bits of a paradoxical subreg. */
if (undefined_operand_subword_p (y, i))
continue;
ypart = operand_subword (y, i, 1, mode);
/* If we can't get a part of Y, put Y into memory if it is a
constant. Otherwise, force it into a register. Then we must