really mandatory?
If either SRC is readonly or length is 1, we can use memcpy. */
- if (dest_align && src_align
- && (readonly_data_expr (src)
- || (host_integerp (len, 1)
- && (MIN (src_align, dest_align) / BITS_PER_UNIT >=
- tree_low_cst (len, 1)))))
+ if (!dest_align || !src_align)
+ return NULL_TREE;
+ if (readonly_data_expr (src)
+ || (host_integerp (len, 1)
+ && (MIN (src_align, dest_align) / BITS_PER_UNIT
+ >= tree_low_cst (len, 1))))
{
tree fn = implicit_built_in_decls[BUILT_IN_MEMCPY];
if (!fn)
return NULL_TREE;
return build_call_expr (fn, 3, dest, src, len);
}
+
+ /* If *src and *dest can't overlap, optimize into memcpy as well. */
+ srcvar = build_fold_indirect_ref (src);
+ destvar = build_fold_indirect_ref (dest);
+ if (srcvar
+ && !TREE_THIS_VOLATILE (srcvar)
+ && destvar
+ && !TREE_THIS_VOLATILE (destvar))
+ {
+ tree src_base, dest_base, fn;
+ HOST_WIDE_INT src_offset = 0, dest_offset = 0;
+ HOST_WIDE_INT size = -1;
+ HOST_WIDE_INT maxsize = -1;
+
+ src_base = srcvar;
+ if (handled_component_p (src_base))
+ src_base = get_ref_base_and_extent (src_base, &src_offset,
+ &size, &maxsize);
+ dest_base = destvar;
+ if (handled_component_p (dest_base))
+ dest_base = get_ref_base_and_extent (dest_base, &dest_offset,
+ &size, &maxsize);
+ if (host_integerp (len, 1))
+ {
+ maxsize = tree_low_cst (len, 1);
+ if (maxsize
+ > INTTYPE_MAXIMUM (HOST_WIDE_INT) / BITS_PER_UNIT)
+ maxsize = -1;
+ else
+ maxsize *= BITS_PER_UNIT;
+ }
+ else
+ maxsize = -1;
+ if (SSA_VAR_P (src_base)
+ && SSA_VAR_P (dest_base))
+ {
+ if (operand_equal_p (src_base, dest_base, 0)
+ && ranges_overlap_p (src_offset, maxsize,
+ dest_offset, maxsize))
+ return NULL_TREE;
+ }
+ else if (TREE_CODE (src_base) == INDIRECT_REF
+ && TREE_CODE (dest_base) == INDIRECT_REF)
+ {
+ if (! operand_equal_p (TREE_OPERAND (src_base, 0),
+ TREE_OPERAND (dest_base, 0), 0)
+ || ranges_overlap_p (src_offset, maxsize,
+ dest_offset, maxsize))
+ return NULL_TREE;
+ }
+ else
+ return NULL_TREE;
+
+ fn = implicit_built_in_decls[BUILT_IN_MEMCPY];
+ if (!fn)
+ return NULL_TREE;
+ return build_call_expr (fn, 3, dest, src, len);
+ }
return NULL_TREE;
}
--- /dev/null
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-times "memmove" 3 "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */
+
+char a[40];
+struct A { char a[30]; };
+
+void
+foo (struct A *p, char *q, char *r)
+{
+ char b[10];
+ __builtin_memmove (&a[1], &a[19], 20);
+ __builtin_memmove (&p->a[1], &p->a[9], 10);
+ __builtin_memmove (q, r, 9);
+}