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

(set_nonzero_bits_and_sign_copies... 

(set_nonzero_bits_and_sign_copies, nonzero_bits): If we have a
positive constant that is negative in the mode it is being used in,
treat it as negative.

From-SVN: r4506
This commit is contained in:
Richard Kenner 1993-05-19 18:09:24 -04:00
parent b310570af3
commit 9afa3d548e
1 changed files with 57 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
gcc/combine.c
View File

@ -692,8 +692,31 @@ set_nonzero_bits_and_sign_copies (x, set)
> GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (set)))))
&& SUBREG_REG (SET_DEST (set)) == x))
{
rtx src = SET_SRC (set);
#ifdef SHORT_IMMEDIATES_SIGN_EXTEND
/* If X is narrower than a word and SRC is a non-negative
constant that would appear negative in the mode of X,
sign-extend it for use in reg_nonzero_bits because some
machines (maybe most) will actually do the sign-extension
and this is the conservative approach.
??? For 2.5, try to tighten up the MD files in this regard
instead of this kludge. */
if (GET_MODE_BITSIZE (GET_MODE (x)) < BITS_PER_WORD
&& GET_CODE (src) == CONST_INT
&& INTVAL (src) > 0
&& 0 != (INTVAL (src)
& ((HOST_WIDE_INT) 1
<< GET_MODE_BITSIZE (GET_MODE (x)))))
src = GEN_INT (INTVAL (src)
| ((HOST_WIDE_INT) (-1)
<< GET_MODE_BITSIZE (GET_MODE (x))));
#endif
reg_nonzero_bits[REGNO (x)]
|= nonzero_bits (SET_SRC (set), nonzero_bits_mode);
|= nonzero_bits (src, nonzero_bits_mode);
num = num_sign_bit_copies (SET_SRC (set), GET_MODE (x));
if (reg_sign_bit_copies[REGNO (x)] == 0
|| reg_sign_bit_copies[REGNO (x)] > num)
@ -6222,14 +6245,46 @@ nonzero_bits (x, mode)
return reg_last_set_nonzero_bits[REGNO (x)];
tem = get_last_value (x);
if (tem)
return nonzero_bits (tem, mode);
{
#ifdef SHORT_IMMEDIATES_SIGN_EXTEND
/* If X is narrower than MODE and TEM is a non-negative
constant that would appear negative in the mode of X,
sign-extend it for use in reg_nonzero_bits because some
machines (maybe most) will actually do the sign-extension
and this is the conservative approach.
??? For 2.5, try to tighten up the MD files in this regard
instead of this kludge. */
if (GET_MODE_BITSIZE (GET_MODE (x)) < mode_width
&& GET_CODE (tem) == CONST_INT
&& INTVAL (tem) > 0
&& 0 != (INTVAL (tem)
& ((HOST_WIDE_INT) 1
<< GET_MODE_BITSIZE (GET_MODE (x)))))
tem = GEN_INT (INTVAL (tem)
| ((HOST_WIDE_INT) (-1)
<< GET_MODE_BITSIZE (GET_MODE (x))));
#endif
return nonzero_bits (tem, mode);
}
else if (nonzero_sign_valid && reg_nonzero_bits[REGNO (x)])
return reg_nonzero_bits[REGNO (x)] & nonzero;
else
return nonzero;
case CONST_INT:
#ifdef SHORT_IMMEDIATES_SIGN_EXTEND
/* If X is negative in MODE, sign-extend the value. */
if (INTVAL (x) > 0
&& 0 != (INTVAL (x)
& ((HOST_WIDE_INT) 1 << GET_MODE_BITSIZE (GET_MODE (x)))))
return (INTVAL (x)
| ((HOST_WIDE_INT) (-1) << GET_MODE_BITSIZE (GET_MODE (x))));
#endif
return INTVAL (x);
#ifdef BYTE_LOADS_ZERO_EXTEND