On Wed, 30 Oct 2013, Richard Biener wrote:
--- gcc/tree-ssa-alias.c (revision 204188)
+++ gcc/tree-ssa-alias.c (working copy)
@@ -567,20 +567,29 @@ void
ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size)
{
HOST_WIDE_INT t1, t2;
ref->ref = NULL_TREE;
if (TREE_CODE (ptr) == SSA_NAME)
{
gimple stmt = SSA_NAME_DEF_STMT (ptr);
if (gimple_assign_single_p (stmt)
&& gimple_assign_rhs_code (stmt) == ADDR_EXPR)
ptr = gimple_assign_rhs1 (stmt);
+ else if (is_gimple_assign (stmt)
+ && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
+ && host_integerp (gimple_assign_rhs2 (stmt), 0)
+ && (t1 = int_cst_value (gimple_assign_rhs2 (stmt))) >= 0)
No need to restrict this to positive offsets I think.
Here is the follow-up patch to remove this restriction
(bootstrap+testsuite on x86_64-unknown-linux-gnu).
I don't really know how safe it is.
I couldn't use host_integerp(,1) since it returns false for (size_t)(-1)
on x86_64, and host_integerp(,0) seemed strange, but I could use it if you
want.
2013-11-01 Marc Glisse <marc.gli...@inria.fr>
gcc/
* tree-ssa-alias.h (ranges_overlap_p): Handle negative offsets.
* tree-ssa-alias.c (ao_ref_init_from_ptr_and_size): Likewise.
gcc/testsuite/
* gcc.dg/tree-ssa/alias-26.c: New file.
--
Marc GlisseIndex: gcc/testsuite/gcc.dg/tree-ssa/alias-26.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/alias-26.c (revision 0)
+++ gcc/testsuite/gcc.dg/tree-ssa/alias-26.c (working copy)
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+void f (const char *c, int *i)
+{
+ *i = 42;
+ __builtin_memcpy (i - 1, c, sizeof (int));
+ if (*i != 42) __builtin_abort();
+}
+
+/* { dg-final { scan-tree-dump-not "abort" "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */
+
Property changes on: gcc/testsuite/gcc.dg/tree-ssa/alias-26.c
___________________________________________________________________
Added: svn:keywords
## -0,0 +1 ##
+Author Date Id Revision URL
\ No newline at end of property
Added: svn:eol-style
## -0,0 +1 ##
+native
\ No newline at end of property
Index: gcc/tree-ssa-alias.c
===================================================================
--- gcc/tree-ssa-alias.c (revision 204267)
+++ gcc/tree-ssa-alias.c (working copy)
@@ -552,42 +552,42 @@ ao_ref_base_alias_set (ao_ref *ref)
alias_set_type
ao_ref_alias_set (ao_ref *ref)
{
if (ref->ref_alias_set != -1)
return ref->ref_alias_set;
ref->ref_alias_set = get_alias_set (ref->ref);
return ref->ref_alias_set;
}
/* Init an alias-oracle reference representation from a gimple pointer
- PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE the the
+ PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE then the
size is assumed to be unknown. The access is assumed to be only
to or after of the pointer target, not before it. */
void
ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size)
{
HOST_WIDE_INT t1, t2, extra_offset = 0;
ref->ref = NULL_TREE;
if (TREE_CODE (ptr) == SSA_NAME)
{
gimple stmt = SSA_NAME_DEF_STMT (ptr);
if (gimple_assign_single_p (stmt)
&& gimple_assign_rhs_code (stmt) == ADDR_EXPR)
ptr = gimple_assign_rhs1 (stmt);
else if (is_gimple_assign (stmt)
&& gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
- && host_integerp (gimple_assign_rhs2 (stmt), 0)
- && (t1 = int_cst_value (gimple_assign_rhs2 (stmt))) >= 0)
+ && TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST)
{
ptr = gimple_assign_rhs1 (stmt);
- extra_offset = BITS_PER_UNIT * t1;
+ extra_offset = BITS_PER_UNIT
+ * int_cst_value (gimple_assign_rhs2 (stmt));
}
}
if (TREE_CODE (ptr) == ADDR_EXPR)
ref->base = get_ref_base_and_extent (TREE_OPERAND (ptr, 0),
&ref->offset, &t1, &t2);
else
{
ref->base = build2 (MEM_REF, char_type_node,
ptr, null_pointer_node);
Index: gcc/tree-ssa-alias.h
===================================================================
--- gcc/tree-ssa-alias.h (revision 204267)
+++ gcc/tree-ssa-alias.h (working copy)
@@ -139,30 +139,30 @@ extern void pt_solution_set_var (struct
extern void dump_pta_stats (FILE *);
extern GTY(()) struct pt_solution ipa_escaped_pt;
/* Return true, if the two ranges [POS1, SIZE1] and [POS2, SIZE2]
overlap. SIZE1 and/or SIZE2 can be (unsigned)-1 in which case the
range is open-ended. Otherwise return false. */
static inline bool
-ranges_overlap_p (unsigned HOST_WIDE_INT pos1,
- unsigned HOST_WIDE_INT size1,
- unsigned HOST_WIDE_INT pos2,
- unsigned HOST_WIDE_INT size2)
+ranges_overlap_p (HOST_WIDE_INT pos1,
+ HOST_WIDE_INT size1,
+ HOST_WIDE_INT pos2,
+ HOST_WIDE_INT size2)
{
if (pos1 >= pos2
- && (size2 == (unsigned HOST_WIDE_INT)-1
+ && (size2 == -1
|| pos1 < (pos2 + size2)))
return true;
if (pos2 >= pos1
- && (size1 == (unsigned HOST_WIDE_INT)-1
+ && (size1 == -1
|| pos2 < (pos1 + size1)))
return true;
return false;
}
#endif /* TREE_SSA_ALIAS_H */
