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tree-ssa-loop-niter.c (refine_bounds_using_guard, [...]): Handle NE_EXPR guards. 

* tree-ssa-loop-niter.c (refine_bounds_using_guard, bound_difference):
	Handle NE_EXPR guards.

From-SVN: r122963
This commit is contained in:
Zdenek Dvorak 2007-03-16 00:47:18 +01:00 committed by Zdenek Dvorak
parent 2ce88bea6d
commit 17b236ed68
2 changed files with 47 additions and 10 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2007-03-15 Zdenek Dvorak <dvorakz@suse.cz>
* tree-ssa-loop-niter.c (refine_bounds_using_guard, bound_difference):
Handle NE_EXPR guards.
2007-03-15 Manuel Lopez-Ibanez <manu@gcc.gnu.org>
PR c++/24924

52
gcc/tree-ssa-loop-niter.c
View File

@ -283,7 +283,7 @@ refine_bounds_using_guard (tree type, tree varx, mpz_t offx,
tree c0, enum tree_code cmp, tree c1,
bounds *bnds)
{
tree varc0, varc1, tmp;
tree varc0, varc1, tmp, ctype;
mpz_t offc0, offc1, loffx, loffy, bnd;
bool lbound = false;
bool no_wrap = nowrap_type_p (type);
@ -295,17 +295,48 @@ refine_bounds_using_guard (tree type, tree varx, mpz_t offx,
case LE_EXPR:
case GT_EXPR:
case GE_EXPR:
STRIP_SIGN_NOPS (c0);
STRIP_SIGN_NOPS (c1);
ctype = TREE_TYPE (c0);
if (!tree_ssa_useless_type_conversion_1 (ctype, type))
return;
break;
case EQ_EXPR:
/* We could derive quite precise information from EQ_EXPR, however, such
a guard is unlikely to appear, so we do not bother with handling it.
TODO. */
a guard is unlikely to appear, so we do not bother with handling
it. */
return;
case NE_EXPR:
/* NE_EXPR comparisons do not contain much of useful information (except for
special cases like comparing with the bounds of the type, TODO). */
/* NE_EXPR comparisons do not contain much of useful information, except for
special case of comparing with the bounds of the type. */
if (TREE_CODE (c1) != INTEGER_CST
|| !INTEGRAL_TYPE_P (type))
return;
/* Ensure that the condition speaks about an expression in the same type
as X and Y. */
ctype = TREE_TYPE (c0);
if (TYPE_PRECISION (ctype) != TYPE_PRECISION (type))
return;
c0 = fold_convert (type, c0);
c1 = fold_convert (type, c1);
if (TYPE_MIN_VALUE (type)
&& operand_equal_p (c1, TYPE_MIN_VALUE (type), 0))
{
cmp = GT_EXPR;
break;
}
if (TYPE_MAX_VALUE (type)
&& operand_equal_p (c1, TYPE_MAX_VALUE (type), 0))
{
cmp = LT_EXPR;
break;
}
return;
default:
return;
@ -422,9 +453,14 @@ bound_difference (struct loop *loop, tree x, tree y, bounds *bnds)
int cnt = 0;
edge e;
basic_block bb;
tree cond, c0, c1, ctype;
tree cond, c0, c1;
enum tree_code cmp;
/* Get rid of unnecessary casts, but preserve the value of
the expressions. */
STRIP_SIGN_NOPS (x);
STRIP_SIGN_NOPS (y);
mpz_init (bnds->below);
mpz_init (bnds->up);
mpz_init (offx);
@ -482,10 +518,6 @@ bound_difference (struct loop *loop, tree x, tree y, bounds *bnds)
c0 = TREE_OPERAND (cond, 0);
cmp = TREE_CODE (cond);
c1 = TREE_OPERAND (cond, 1);
ctype = TREE_TYPE (c0);
if (!tree_ssa_useless_type_conversion_1 (ctype, type))
continue;
if (e->flags & EDGE_FALSE_VALUE)
cmp = invert_tree_comparison (cmp, false);