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From: Glen Nakamura <glen@imodulo.com>
To: nobody@gcc.gnu.org
Cc: gcc-prs@gcc.gnu.org,
Subject: Re: optimization/6822: GCC 3.1.1 - Internal compiler error in extract_insn, at recog.c:2132
Date: Tue, 28 May 2002 08:16:00 -0000 [thread overview]
Message-ID: <20020528145605.10437.qmail@sources.redhat.com> (raw)
The following reply was made to PR optimization/6822; it has been noted by GNATS.
From: Glen Nakamura <glen@imodulo.com>
To: gcc-gnats@gcc.gnu.org
Cc:
Subject: Re: optimization/6822: GCC 3.1.1 - Internal compiler error in extract_insn, at recog.c:2132
Date: Tue, 28 May 2002 04:49:41 -1000
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http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6822
2002-05-28 Glen Nakamura <glen@imodulo.com>
* fold-const.c (fold): Modify the transformation of a comparison
against the highest or lowest integer value to adjust for the
previous transformation which converts 'X >= CST to X > (CST - 1)'
and 'X < CST to X <= (CST - 1)'.
The patch allows the compiler to reduce unsigned X < ~0 to X != ~0.
It also reduces unsigned X <= (~0 - 1) to X != ~0 which the original patch
missed... e.g. gcc.c-torture/execute/loop-2c.c execution, -Os
would fail again on i586-pc-linux-gnu if we changed:
for (p = &a[b], i = b; --i < ~0; )
*--p = i * 3 + o;
to:
for (p = &a[b], i = b; --i <= (~0 - 1); )
*--p = i * 3 + o;
With this patch, both cases should work...
- Glen Nakamura
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Content-Disposition: attachment; filename="fold.diff"
Index: fold-const.c
===================================================================
RCS file: /cvsroot/gcc/gcc/gcc/fold-const.c,v
retrieving revision 1.185.2.2
diff -c -3 -p -r1.185.2.2 fold-const.c
*** fold-const.c 23 Apr 2002 23:20:00 -0000 1.185.2.2
--- fold-const.c 27 May 2002 21:11:18 -0000
*************** fold (expr)
*** 6490,6496 ****
}
}
! /* Change X >= CST to X > (CST - 1) if CST is positive. */
if (TREE_CODE (arg1) == INTEGER_CST
&& TREE_CODE (arg0) != INTEGER_CST
&& tree_int_cst_sgn (arg1) > 0)
--- 6490,6497 ----
}
}
! /* Change X >= CST to X > (CST - 1) and X < CST to X <= (CST - 1)
! if CST is positive. */
if (TREE_CODE (arg1) == INTEGER_CST
&& TREE_CODE (arg0) != INTEGER_CST
&& tree_int_cst_sgn (arg1) > 0)
*************** fold (expr)
*** 6753,6777 ****
return omit_one_operand (type,
convert (type, integer_zero_node),
arg0);
- case GE_EXPR:
- TREE_SET_CODE (t, EQ_EXPR);
- break;
-
case LE_EXPR:
return omit_one_operand (type,
convert (type, integer_one_node),
arg0);
! case LT_EXPR:
! TREE_SET_CODE (t, NE_EXPR);
break;
default:
break;
}
else if (TREE_INT_CST_HIGH (arg1) == -1
&& (TREE_INT_CST_LOW (arg1)
! == ((unsigned HOST_WIDE_INT) 1 << (width - 1)))
&& ! TREE_UNSIGNED (TREE_TYPE (arg1)))
switch (TREE_CODE (t))
{
--- 6754,6796 ----
return omit_one_operand (type,
convert (type, integer_zero_node),
arg0);
case LE_EXPR:
return omit_one_operand (type,
convert (type, integer_one_node),
arg0);
!
! /* The GE_EXPR and LT_EXPR cases are unnecessary because a
! previous optimization converted X >= CST to X > (CST - 1)
! and X < CST to X <= (CST - 1). These two cases are handled
! in the next switch statement. */
!
! default:
break;
+ }
+ else if (TREE_INT_CST_HIGH (arg1) == 0
+ && (TREE_INT_CST_LOW (arg1)
+ == ((unsigned HOST_WIDE_INT) 1 << (width - 1)) - 2)
+ && ! TREE_UNSIGNED (TREE_TYPE (arg1)))
+ switch (TREE_CODE (t))
+ {
+ case GT_EXPR:
+ code = EQ_EXPR;
+ arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0);
+ t = build (code, type, TREE_OPERAND (t, 0), arg1);
+ break;
+ case LE_EXPR:
+ code = NE_EXPR;
+ arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0);
+ t = build (code, type, TREE_OPERAND (t, 0), arg1);
+ break;
default:
break;
}
else if (TREE_INT_CST_HIGH (arg1) == -1
&& (TREE_INT_CST_LOW (arg1)
! == ((unsigned HOST_WIDE_INT) -1 << (width - 1)))
&& ! TREE_UNSIGNED (TREE_TYPE (arg1)))
switch (TREE_CODE (t))
{
*************** fold (expr)
*** 6780,6785 ****
--- 6799,6805 ----
convert (type, integer_zero_node),
arg0);
case LE_EXPR:
+ code = EQ_EXPR;
TREE_SET_CODE (t, EQ_EXPR);
break;
*************** fold (expr)
*** 6788,6793 ****
--- 6808,6814 ----
convert (type, integer_one_node),
arg0);
case GT_EXPR:
+ code = NE_EXPR;
TREE_SET_CODE (t, NE_EXPR);
break;
*************** fold (expr)
*** 6830,6847 ****
return omit_one_operand (type,
convert (type, integer_zero_node),
arg0);
- case GE_EXPR:
- TREE_SET_CODE (t, EQ_EXPR);
- break;
-
case LE_EXPR:
return omit_one_operand (type,
convert (type, integer_one_node),
arg0);
! case LT_EXPR:
! TREE_SET_CODE (t, NE_EXPR);
break;
default:
break;
}
--- 6851,6886 ----
return omit_one_operand (type,
convert (type, integer_zero_node),
arg0);
case LE_EXPR:
return omit_one_operand (type,
convert (type, integer_one_node),
arg0);
!
! /* The GE_EXPR and LT_EXPR cases are unnecessary because a
! previous optimization converted X >= CST to X > (CST - 1)
! and X < CST to X <= (CST - 1). These two cases are handled
! in the next switch statement. */
!
! default:
break;
+ }
+ else if (TREE_INT_CST_HIGH (arg1) == 0
+ && (TREE_INT_CST_LOW (arg1)
+ == ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 2)
+ && TREE_UNSIGNED (TREE_TYPE (arg1)))
+ switch (TREE_CODE (t))
+ {
+ case GT_EXPR:
+ code = EQ_EXPR;
+ arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0);
+ t = build (code, type, TREE_OPERAND (t, 0), arg1);
+ break;
+ case LE_EXPR:
+ code = NE_EXPR;
+ arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0);
+ t = build (code, type, TREE_OPERAND (t, 0), arg1);
+ break;
default:
break;
}
--FL5UXtIhxfXey3p5--
next reply other threads:[~2002-05-28 14:56 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-05-28 8:16 Glen Nakamura [this message]
-- strict thread matches above, loose matches on Subject: below --
2002-06-02 13:06 Glen Nakamura
2002-06-02 12:36 Richard Henderson
2002-05-30 16:56 rth
2002-05-29 12:16 Richard Henderson
2002-05-29 10:36 Richard Henderson
2002-05-29 9:44 Glen Nakamura
2002-05-29 9:16 Eric Botcazou
2002-05-29 0:46 Glen Nakamura
2002-05-28 18:16 Glen Nakamura
2002-05-28 17:16 Eric Botcazou
2002-05-28 16:36 Eric Botcazou
2002-05-28 11:00 Richard Henderson
2002-05-28 7:10 Glen Nakamura
2002-05-26 16:46 paolo
2002-05-26 12:26 glen
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