This patch adds code to expand_builtin_strncmp so it also attempts
expansion via cmpstrnsi in the case where c_strlen() returns NULL for
both string arguments, meaning that neither one is a constant.
--
Aaron Sawdey, Ph.D. acsaw...@linux.vnet.ibm.com
050-2/C113 (507) 253-7520 home: 507/263-0782
IBM Linux Technology Center - PPC Toolchain
Index: builtins.c
===================================================================
--- builtins.c (revision 241743)
+++ builtins.c (working copy)
@@ -3929,61 +3929,85 @@
unsigned int arg1_align = get_pointer_alignment (arg1) / BITS_PER_UNIT;
unsigned int arg2_align = get_pointer_alignment (arg2) / BITS_PER_UNIT;
+ /* If we don't have POINTER_TYPE, call the function. */
+ if (arg1_align == 0 || arg2_align == 0)
+ return NULL_RTX;
+
len1 = c_strlen (arg1, 1);
len2 = c_strlen (arg2, 1);
- if (len1)
- len1 = size_binop_loc (loc, PLUS_EXPR, ssize_int (1), len1);
- if (len2)
- len2 = size_binop_loc (loc, PLUS_EXPR, ssize_int (1), len2);
+ if (!len1 && !len2)
+ {
+ /* If neither arg1 nor arg2 are constant strings. */
+ /* Stabilize the arguments in case gen_cmpstrnsi fails. */
+ arg1 = builtin_save_expr (arg1);
+ arg2 = builtin_save_expr (arg2);
+ /* Use save_expr here because cmpstrnsi may modify arg3
+ and builtin_save_expr() doesn't force the save to happen. */
+ len = save_expr (arg3);
+ len = fold_convert_loc (loc, sizetype, len);
+ }
+ else
+ {
+ if (len1)
+ len1 = size_binop_loc (loc, PLUS_EXPR, ssize_int (1), len1);
+ if (len2)
+ len2 = size_binop_loc (loc, PLUS_EXPR, ssize_int (1), len2);
- /* If we don't have a constant length for the first, use the length
- of the second, if we know it. We don't require a constant for
- this case; some cost analysis could be done if both are available
- but neither is constant. For now, assume they're equally cheap,
- unless one has side effects. If both strings have constant lengths,
- use the smaller. */
+ /* If we don't have a constant length for the first, use the length
+ of the second, if we know it. We don't require a constant for
+ this case; some cost analysis could be done if both are available
+ but neither is constant. For now, assume they're equally cheap,
+ unless one has side effects. If both strings have constant lengths,
+ use the smaller. */
- if (!len1)
- len = len2;
- else if (!len2)
- len = len1;
- else if (TREE_SIDE_EFFECTS (len1))
- len = len2;
- else if (TREE_SIDE_EFFECTS (len2))
- len = len1;
- else if (TREE_CODE (len1) != INTEGER_CST)
- len = len2;
- else if (TREE_CODE (len2) != INTEGER_CST)
- len = len1;
- else if (tree_int_cst_lt (len1, len2))
- len = len1;
- else
- len = len2;
+ if (!len1)
+ len = len2;
+ else if (!len2)
+ len = len1;
+ else if (TREE_SIDE_EFFECTS (len1))
+ len = len2;
+ else if (TREE_SIDE_EFFECTS (len2))
+ len = len1;
+ else if (TREE_CODE (len1) != INTEGER_CST)
+ len = len2;
+ else if (TREE_CODE (len2) != INTEGER_CST)
+ len = len1;
+ else if (tree_int_cst_lt (len1, len2))
+ len = len1;
+ else
+ len = len2;
- /* If both arguments have side effects, we cannot optimize. */
- if (!len || TREE_SIDE_EFFECTS (len))
- return NULL_RTX;
+ /* If both arguments have side effects, we cannot optimize. */
+ if (TREE_SIDE_EFFECTS (len))
+ return NULL_RTX;
- /* The actual new length parameter is MIN(len,arg3). */
- len = fold_build2_loc (loc, MIN_EXPR, TREE_TYPE (len), len,
- fold_convert_loc (loc, TREE_TYPE (len), arg3));
+ /* The actual new length parameter is MIN(len,arg3). */
+ len = fold_build2_loc (loc, MIN_EXPR, TREE_TYPE (len), len,
+ fold_convert_loc (loc, TREE_TYPE (len), arg3));
- /* If we don't have POINTER_TYPE, call the function. */
- if (arg1_align == 0 || arg2_align == 0)
- return NULL_RTX;
+ /* Stabilize the arguments in case gen_cmpstrnsi fails. */
+ arg1 = builtin_save_expr (arg1);
+ arg2 = builtin_save_expr (arg2);
+ len = builtin_save_expr (len);
+ }
- /* Stabilize the arguments in case gen_cmpstrnsi fails. */
- arg1 = builtin_save_expr (arg1);
- arg2 = builtin_save_expr (arg2);
- len = builtin_save_expr (len);
-
arg1_rtx = get_memory_rtx (arg1, len);
arg2_rtx = get_memory_rtx (arg2, len);
arg3_rtx = expand_normal (len);
+
+ /* Set MEM_SIZE as appropriate. This will only happen in
+ the case where incoming arg3 is constant and arg1/arg2 are not. */
+ if (CONST_INT_P (arg3_rtx))
+ {
+ set_mem_size (arg1_rtx, INTVAL (arg3_rtx));
+ set_mem_size (arg2_rtx, INTVAL (arg3_rtx));
+ }
+
result = expand_cmpstrn_or_cmpmem (cmpstrn_icode, target, arg1_rtx,
arg2_rtx, TREE_TYPE (len), arg3_rtx,
MIN (arg1_align, arg2_align));
+
if (result)
{
/* Return the value in the proper mode for this function. */
