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combine.c (combine_simplify_rtx): Don't create an if_then_else unless both args are general_operand.

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* combine.c (combine_simplify_rtx): Don't create an if_then_else
        unless both args are general_operand.  Don't canonicalize plus
        to ior unless it helps.

From-SVN: r34247
This commit is contained in:
Richard Henderson 2000-05-29 00:29:13 -07:00 committed by Richard Henderson
parent 7b40bc6bda
commit 085f17143f
2 changed files with 50 additions and 29 deletions
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4
gcc/ChangeLog
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@ -1,5 +1,9 @@
2000-05-29 Richard Henderson <rth@cygnus.com>
* combine.c (combine_simplify_rtx): Don't create an if_then_else
unless both args are general_operand. Don't canonicalize plus
to ior unless it helps.
* toplev.c (rest_of_compilation): Set no_new_pseudos after flow1;
instead track register_life_up_to_date. Toggle no_new_pseudos
around if_convert.

75
gcc/combine.c
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@ -3589,37 +3589,44 @@ combine_simplify_rtx (x, op0_mode, last, in_dest)
true = subst (true, pc_rtx, pc_rtx, 0, 0);
false = subst (false, pc_rtx, pc_rtx, 0, 0);
/* Restarting if we generate a store-flag expression will cause
us to loop. Just drop through in this case. */
/* If true and false are not general_operands, an if_then_else
is unlikely to be simpler. */
if (general_operand (true, VOIDmode)
&& general_operand (false, VOIDmode))
{
/* Restarting if we generate a store-flag expression will cause
us to loop. Just drop through in this case. */
/* If the result values are STORE_FLAG_VALUE and zero, we can
just make the comparison operation. */
if (true == const_true_rtx && false == const0_rtx)
x = gen_binary (cond_code, mode, cond, cop1);
else if (true == const0_rtx && false == const_true_rtx)
x = gen_binary (reverse_condition (cond_code), mode, cond, cop1);
/* If the result values are STORE_FLAG_VALUE and zero, we can
just make the comparison operation. */
if (true == const_true_rtx && false == const0_rtx)
x = gen_binary (cond_code, mode, cond, cop1);
else if (true == const0_rtx && false == const_true_rtx)
x = gen_binary (reverse_condition (cond_code),
mode, cond, cop1);
/* Likewise, we can make the negate of a comparison operation
if the result values are - STORE_FLAG_VALUE and zero. */
else if (GET_CODE (true) == CONST_INT
&& INTVAL (true) == - STORE_FLAG_VALUE
&& false == const0_rtx)
x = gen_unary (NEG, mode, mode,
gen_binary (cond_code, mode, cond, cop1));
else if (GET_CODE (false) == CONST_INT
&& INTVAL (false) == - STORE_FLAG_VALUE
&& true == const0_rtx)
x = gen_unary (NEG, mode, mode,
gen_binary (reverse_condition (cond_code),
mode, cond, cop1));
else
return gen_rtx_IF_THEN_ELSE (mode,
gen_binary (cond_code, VOIDmode,
cond, cop1),
true, false);
/* Likewise, we can make the negate of a comparison operation
if the result values are - STORE_FLAG_VALUE and zero. */
else if (GET_CODE (true) == CONST_INT
&& INTVAL (true) == - STORE_FLAG_VALUE
&& false == const0_rtx)
x = gen_unary (NEG, mode, mode,
gen_binary (cond_code, mode, cond, cop1));
else if (GET_CODE (false) == CONST_INT
&& INTVAL (false) == - STORE_FLAG_VALUE
&& true == const0_rtx)
x = gen_unary (NEG, mode, mode,
gen_binary (reverse_condition (cond_code),
mode, cond, cop1));
else
return gen_rtx_IF_THEN_ELSE (mode,
gen_binary (cond_code, VOIDmode,
cond, cop1),
true, false);
code = GET_CODE (x);
op0_mode = VOIDmode;
code = GET_CODE (x);
op0_mode = VOIDmode;
}
}
}
@ -4229,7 +4236,17 @@ combine_simplify_rtx (x, op0_mode, last, in_dest)
if (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT
&& (nonzero_bits (XEXP (x, 0), mode)
& nonzero_bits (XEXP (x, 1), mode)) == 0)
return gen_binary (IOR, mode, XEXP (x, 0), XEXP (x, 1));
{
/* Try to simplify the expression further. */
rtx tor = gen_binary (IOR, mode, XEXP (x, 0), XEXP (x, 1));
temp = combine_simplify_rtx (tor, mode, last, in_dest);
/* If we could, great. If not, do not go ahead with the IOR
replacement, since PLUS appears in many special purpose
address arithmetic instructions. */
if (GET_CODE (temp) != CLOBBER && temp != tor)
return temp;
}
break;
case MINUS: