For 32-bit targets, when address of data reference crosses the boundary of 0x80000000, signed comparisons of address expressions will lead to incorrect results. Additional comments and patches are also available in the bug database.
My fix is:
1. In LFTR, force comparison of address expressions to use unsigned type for
32-bit targets.
2. Allow results of pointer arithmetic "p + a" and "p - a" (where "p" is a
pointer or an address expression, "a" is neither a pointer nor an address
expression") to be recognized as an address expression.
Index: be/opt/opt_htable.cxx
===================================================================
--- be/opt/opt_htable.cxx (revision 3488)
+++ be/opt/opt_htable.cxx (working copy)
@@ -5102,8 +5102,11 @@
if (res0 == ADDRESSABILITY_UNKNOWN)
return ADDRESSABILITY_UNKNOWN;
res1 = Opnd(1)->Check_if_result_is_address(opt_stab);
- if (res1 == ADDRESSABILITY_UNKNOWN)
+ if (res1 == ADDRESSABILITY_UNKNOWN) {
+ if (res0 == ADDRESSABILITY_IS_ADDRESS)
+ return res0;
return ADDRESSABILITY_UNKNOWN;
+ }
if (res0 == res1) {
if (res0 == ADDRESSABILITY_IS_ADDRESS)
return ADDRESSABILITY_NOT_ADDRESS;
Index: be/opt/opt_lftr2.cxx
===================================================================
--- be/opt/opt_lftr2.cxx (revision 3488)
+++ be/opt/opt_lftr2.cxx (working copy)
@@ -1216,11 +1216,18 @@
// adjust operator of new comparison
OPERATOR new_compare_opr = comparison_cr->Opr();
-#ifdef KEY
+#ifdef KEY
MTYPE new_compare_type = tempcr->Dtyp();
// do not change signedness of comparison since that could change semantics
new_compare_type = Mtype_TransferSign(comparison_cr->Dsctyp(),
new_compare_type);
+ if (Is_Target_32bit()
+ && (addressable == ADDRESSABILITY_IS_ADDRESS)
+ && MTYPE_is_signed(new_compare_type)) {
+ // For 32-bit targets, force comparison of address expressions to be
unsigned.
+ new_compare_type = Mtype_from_mtype_class_and_size(MTYPE_CLASS_UNSIGNED,
+
MTYPE_size_min(new_compare_type)/8);
+ }
#else
MTYPE new_compare_type = comparison_cr->Dsctyp();
if (addressable == ADDRESSABILITY_IS_ADDRESS &&
odc
Description: odc
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