[PATCH] Fix extract_range_from_cond (PR tree-optimization/19060)
Jakub Jelinek
jakub@redhat.com
Fri Jan 7 09:26:00 GMT 2005
On Wed, Jan 05, 2005 at 11:49:45AM -0700, Jeffrey A Law wrote:
> We're probably best off doing two things:
>
> 1. Fixing fold so that it handles x < TYPE_MIN_VALUE (TREE_TYPE (x))
> (I thought it did that already, so we need to figure out why it
> didn't trigger).
>
> 2. For GT TYPE_MAX_VALUE, don't record anything. Simliarly for
> LT TYPE_MIN_VALUE.
>
> 3. Document this code better (still in my TODO queue).
Here is what I have bootstrapped/regtested on
{i386,x86_64,ia64,ppc,ppc64,s390,s390x}-redhat-linux.
The problem with 1. is that fold only optimized this for
<= HOST_BITS_PER_WIDE_INT wide integer types, but that's easily fixable.
This exact patch has an gcc_unreachable there, so relies on fold optimizing
this out. I have tried also:
+ /* The last element has not been processed. Process it now.
+ record_range should ensure for cond inverted is not set.
+ This call can only fail if cond is x < min or x > max,
+ which fold should have optimized into false.
+ If that doesn't happen, just pretend all values are
+ in the range. */
+ if (! extract_range_from_cond (element->cond, &tmp_high,
+ &tmp_low, &dummy))
+ {
+ tree type = TREE_TYPE (TREE_OPERAND (element->cond, 1));
+ tmp_low = TYPE_MIN_VALUE (type);
+ tmp_high = TYPE_MAX_VALUE (type);
+ }
+ else
+ gcc_assert (dummy == 0);
+
which has a safety net just in the highly unprobable case fold doesn't
optimize such comparisons out, would that be preferable or do you think
it is best to test this in record_range and don't record that?
2005-01-07 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/19060
* tree-ssa-dom.c (extract_range_from_cond) <case LT_EXPR, GT_EXPR>:
Return 0 if op1 <= TYPE_MIN_VALUE () resp. op1 >= TYPE_MAX_VALUE ().
(simplify_cond_and_lookup_avail_expr): Add assert for dummy == 0
and handle extract_range_from_cond returning false.
* fold-const.c (fold): Optimize comparisons with min/max even for
width > HOST_BITS_PER_WIDE_INT.
* gcc.c-torture/execute/20050104-1.c: New test.
--- gcc/fold-const.c.jj 2005-01-06 12:09:52.782028982 +0100
+++ gcc/fold-const.c 2005-01-06 12:41:24.559957382 +0100
@@ -8436,28 +8436,57 @@ fold (tree expr)
if (TREE_CODE (arg1) == INTEGER_CST
&& ! TREE_CONSTANT_OVERFLOW (arg1)
- && width <= HOST_BITS_PER_WIDE_INT
+ && width <= 2 * HOST_BITS_PER_WIDE_INT
&& (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
|| POINTER_TYPE_P (TREE_TYPE (arg1))))
{
- unsigned HOST_WIDE_INT signed_max;
- unsigned HOST_WIDE_INT max, min;
+ HOST_WIDE_INT signed_max_hi;
+ unsigned HOST_WIDE_INT signed_max_lo;
+ unsigned HOST_WIDE_INT max_hi, max_lo, min_hi, min_lo;
- signed_max = ((unsigned HOST_WIDE_INT) 1 << (width - 1)) - 1;
-
- if (TYPE_UNSIGNED (TREE_TYPE (arg1)))
+ if (width <= HOST_BITS_PER_WIDE_INT)
{
- max = ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 1;
- min = 0;
+ signed_max_lo = ((unsigned HOST_WIDE_INT) 1 << (width - 1))
+ - 1;
+ signed_max_hi = 0;
+ max_hi = 0;
+
+ if (TYPE_UNSIGNED (TREE_TYPE (arg1)))
+ {
+ max_lo = ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 1;
+ min_lo = 0;
+ min_hi = 0;
+ }
+ else
+ {
+ max_lo = signed_max_lo;
+ min_lo = ((unsigned HOST_WIDE_INT) -1 << (width - 1));
+ min_hi = -1;
+ }
}
else
{
- max = signed_max;
- min = ((unsigned HOST_WIDE_INT) -1 << (width - 1));
+ width -= HOST_BITS_PER_WIDE_INT;
+ signed_max_lo = -1;
+ signed_max_hi = ((unsigned HOST_WIDE_INT) 1 << (width - 1))
+ - 1;
+ max_lo = -1;
+ min_lo = 0;
+
+ if (TYPE_UNSIGNED (TREE_TYPE (arg1)))
+ {
+ max_hi = ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 1;
+ min_hi = 0;
+ }
+ else
+ {
+ max_hi = signed_max_hi;
+ min_hi = ((unsigned HOST_WIDE_INT) -1 << (width - 1));
+ }
}
- if (TREE_INT_CST_HIGH (arg1) == 0
- && TREE_INT_CST_LOW (arg1) == max)
+ if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1) == max_hi
+ && TREE_INT_CST_LOW (arg1) == max_lo)
switch (code)
{
case GT_EXPR:
@@ -8478,8 +8507,9 @@ fold (tree expr)
default:
break;
}
- else if (TREE_INT_CST_HIGH (arg1) == 0
- && TREE_INT_CST_LOW (arg1) == max - 1)
+ else if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1)
+ == max_hi
+ && TREE_INT_CST_LOW (arg1) == max_lo - 1)
switch (code)
{
case GT_EXPR:
@@ -8491,8 +8521,9 @@ fold (tree expr)
default:
break;
}
- else if (TREE_INT_CST_HIGH (arg1) == (min ? -1 : 0)
- && TREE_INT_CST_LOW (arg1) == min)
+ else if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1)
+ == min_hi
+ && TREE_INT_CST_LOW (arg1) == min_lo)
switch (code)
{
case LT_EXPR:
@@ -8510,8 +8541,9 @@ fold (tree expr)
default:
break;
}
- else if (TREE_INT_CST_HIGH (arg1) == (min ? -1 : 0)
- && TREE_INT_CST_LOW (arg1) == min + 1)
+ else if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1)
+ == min_hi
+ && TREE_INT_CST_LOW (arg1) == min_lo + 1)
switch (code)
{
case GE_EXPR:
@@ -8525,8 +8557,8 @@ fold (tree expr)
}
else if (!in_gimple_form
- && TREE_INT_CST_HIGH (arg1) == 0
- && TREE_INT_CST_LOW (arg1) == signed_max
+ && TREE_INT_CST_HIGH (arg1) == signed_max_hi
+ && TREE_INT_CST_LOW (arg1) == signed_max_lo
&& TYPE_UNSIGNED (TREE_TYPE (arg1))
/* signed_type does not work on pointer types. */
&& INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
--- gcc/tree-ssa-dom.c.jj 2004-12-28 22:03:26.000000000 +0100
+++ gcc/tree-ssa-dom.c 2005-01-06 14:03:56.086431506 +0100
@@ -1,5 +1,5 @@
/* SSA Dominator optimizations for trees
- Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
Contributed by Diego Novillo <dnovillo@redhat.com>
This file is part of GCC.
@@ -2088,10 +2088,18 @@ simplify_cond_and_lookup_avail_expr (tre
tree tmp_high, tmp_low;
int dummy;
- /* The last element has not been processed. Process it now. */
- extract_range_from_cond (element->cond, &tmp_high,
- &tmp_low, &dummy);
-
+ /* The last element has not been processed. Process it now.
+ record_range should ensure for cond inverted is not set.
+ This call can only fail if cond is x < min or x > max,
+ which fold should have optimized into false.
+ If that doesn't happen, just pretend all values are
+ in the range. */
+ if (! extract_range_from_cond (element->cond, &tmp_high,
+ &tmp_low, &dummy))
+ gcc_unreachable ();
+ else
+ gcc_assert (dummy == 0);
+
/* If this is the only element, then no merging is necessary,
the high/low values from extract_range_from_cond are all
we need. */
@@ -3204,8 +3212,10 @@ extract_range_from_cond (tree cond, tree
break;
case GT_EXPR:
- low = int_const_binop (PLUS_EXPR, op1, integer_one_node, 1);
high = TYPE_MAX_VALUE (type);
+ if (!tree_int_cst_lt (op1, high))
+ return 0;
+ low = int_const_binop (PLUS_EXPR, op1, integer_one_node, 1);
inverted = 0;
break;
@@ -3216,8 +3226,10 @@ extract_range_from_cond (tree cond, tree
break;
case LT_EXPR:
- high = int_const_binop (MINUS_EXPR, op1, integer_one_node, 1);
low = TYPE_MIN_VALUE (type);
+ if (tree_int_cst_equal (op1, low) || tree_int_cst_lt (op1, low))
+ return 0;
+ high = int_const_binop (MINUS_EXPR, op1, integer_one_node, 1);
inverted = 0;
break;
--- gcc/testsuite/gcc.c-torture/execute/20050104-1.c.jj 2005-01-04 17:58:38.000000000 +0100
+++ gcc/testsuite/gcc.c-torture/execute/20050104-1.c 2005-01-04 17:59:01.000000000 +0100
@@ -0,0 +1,23 @@
+/* PR tree-optimization/19060 */
+
+void abort (void);
+
+static
+long long min ()
+{
+ return -__LONG_LONG_MAX__ - 1;
+}
+
+void
+foo (long long j)
+{
+ if (j > 10 || j < min ())
+ abort ();
+}
+
+int
+main (void)
+{
+ foo (10);
+ return 0;
+}
Jakub
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