------- Comment #24 from rguenth at gcc dot gnu dot org 2007-04-21 18:38
-------
Actually the handle_ptr_arith change made a difference as we (luckily?)
for D.2147_17 = D.2144_14 + D.2146_16
D.2144_14 = a_11->begin;
D.2145_15 = i_1 * 4;
D.2146_16 = (const int *) D.2145_15;
D.2147_17 = D.2144_14 + D.2146_16;
add a constraint for offset zero (that's pure luck) for D.2144_14. So, the
difference in constraints good vs. bad is
@@ -26,10 +26,10 @@
D.2144_14 = *a_11
D.2146_16 = &ANYTHING
D.2147_17 = D.2144_14
+D.2147_17 = D.2146_16
ESCAPED_VARS = D.2092_25
Collapsing static cycles and doing variable substitution:
-Collapsing D.2147_17 into D.2144_14
Collapsing this_7 into D.2140_6
Collapsing NONLOCAL.8 into ESCAPED_VARS
@@ -54,7 +54,7 @@
a_11 = { D.2142 }
D.2144_14 = { D.2141 D.2141.32 }
D.2146_16 = { ANYTHING }
-D.2147_17 = { D.2141 D.2141.32 }
+D.2147_17 = { ANYTHING D.2141 D.2141.32 }
D.2092_25 = { }
main: Total number of aliased vops: 3
Unrelated to this the following resolves possible problems in handle_ptr_arith:
Index: tree-ssa-structalias.c
===================================================================
--- tree-ssa-structalias.c (revision 124018)
+++ tree-ssa-structalias.c (working copy)
@@ -3287,7 +3287,7 @@ handle_ptr_arith (VEC (ce_s, heap) *lhsc
unsigned int i = 0;
unsigned int j = 0;
VEC (ce_s, heap) *temp = NULL;
- unsigned int rhsoffset = 0;
+ unsigned HOST_WIDE_INT rhsoffset = 0;
if (TREE_CODE (expr) != PLUS_EXPR
&& TREE_CODE (expr) != MINUS_EXPR)
@@ -3298,8 +3298,10 @@ handle_ptr_arith (VEC (ce_s, heap) *lhsc
get_constraint_for (op0, &temp);
if (POINTER_TYPE_P (TREE_TYPE (op0))
- && TREE_CODE (op1) == INTEGER_CST
- && TREE_CODE (expr) == PLUS_EXPR)
+ && host_integerp (op1, 0)
+ && TREE_CODE (expr) == PLUS_EXPR
+ /* Make sure the pointer offset is positive. */
+ && tree_int_cst_msb (op1) == 0)
{
rhsoffset = TREE_INT_CST_LOW (op1) * BITS_PER_UNIT;
}
though that last multiplication may still overflow.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30567
