On 5 December 2016 at 23:47, Jakub Jelinek <ja...@redhat.com> wrote:
> On Mon, Dec 05, 2016 at 11:32:15PM +0530, Prathamesh Kulkarni wrote:
>> So I had to check if SSA_NAME_DEF_STMT (rhs2) was call to strstr
>> rather than rhs1.
>
> Then you need to test both whether it is strstr (s, t) == s or
> s == strstr (s, t).
>
>> + gassign *ga = gimple_build_assign (lhs, code,
>> + strcmp_lhs, zero);
>
> The formatting is wrong here.
>
>> + gsi_replace (&gsi, ga, false);
>> + }
>> + }
>> + }
>> + }
>> + }
>> + }
>> else if (TREE_CODE (lhs) != SSA_NAME && !TREE_SIDE_EFFECTS (lhs))
>> {
>> tree type = TREE_TYPE (lhs);
>> @@ -2505,7 +2554,7 @@ const pass_data pass_data_strlen =
>> 0, /* properties_provided */
>> 0, /* properties_destroyed */
>> 0, /* todo_flags_start */
>> - 0, /* todo_flags_finish */
>> + TODO_update_ssa, /* todo_flags_finish */
>
> No, please don't. Just make sure to build proper SSA right away.
Hi,
Thanks for the suggestions, I have tried to modify the patch accordingly.
Does this version look OK ?
Bootstrap+tested on x86_64-unknown-linux-gnu with --enable-languages=all,ada
Cross tested on arm*-*-*, aarch64*-*-*.
Thanks,
Prathamesh
>
> Jakub
2016-12-07 Prathamesh Kulkarni <prathamesh.kulka...@linaro.org>
* tree-ssa-strlen.c (strlen_optimize_stmt): Fold strstr(s, t) == s to
memcmp (s, t, strlen (t)) == 0.
Include tree-into-ssa.h.
testsuite/
* gcc.dg/strlenopt-30.c: New test-case.
diff --git a/gcc/testsuite/gcc.dg/strlenopt-30.c
b/gcc/testsuite/gcc.dg/strlenopt-30.c
new file mode 100644
index 0000000..603e23c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strlenopt-30.c
@@ -0,0 +1,42 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-strlen" } */
+
+__attribute__((no_icf))
+_Bool f1(char *s)
+{
+ return __builtin_strstr (s, "hello") == s;
+}
+
+__attribute__((no_icf))
+_Bool f2(char *s)
+{
+ return s == __builtin_strstr (s, "hello");
+}
+
+__attribute__((no_icf))
+_Bool f3(char *s)
+{
+ return s != __builtin_strstr (s, "hello");
+}
+
+__attribute__((no_icf))
+_Bool f4(char *s, char *t)
+{
+ return __builtin_strstr (s, t) == s;
+}
+
+/* Do not perform transform in this case, since
+ t1 doesn't have single use. */
+
+__attribute__((no_icf))
+_Bool f5(char *s, char *t)
+{
+ void foo(char *);
+
+ char *t1 = __builtin_strstr (s, t);
+ foo (t1);
+ return (t1 == s);
+}
+
+/* { dg-final { scan-tree-dump-times "__builtin_memcmp" 4 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "__builtin_strlen" 1 "strlen" } } */
diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c
index 339812e..b7f4cee 100644
--- a/gcc/tree-ssa-strlen.c
+++ b/gcc/tree-ssa-strlen.c
@@ -45,6 +45,7 @@ along with GCC; see the file COPYING3. If not see
#include "ipa-chkp.h"
#include "tree-hash-traits.h"
#include "builtins.h"
+#include "tree-into-ssa.h"
/* A vector indexed by SSA_NAME_VERSION. 0 means unknown, positive value
is an index into strinfo vector, negative value stands for
@@ -2302,7 +2303,94 @@ strlen_optimize_stmt (gimple_stmt_iterator *gsi)
else if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
handle_pointer_plus (gsi);
}
- else if (TREE_CODE (lhs) != SSA_NAME && !TREE_SIDE_EFFECTS (lhs))
+
+ /* Fold strstr (s, t) == s to memcmp (s, t, strlen (t)) == 0.
+ if var holding return value of strstr has single use. */
+
+ else if (TREE_CODE (lhs) == SSA_NAME && INTEGRAL_TYPE_P (TREE_TYPE
(lhs)))
+ {
+ enum tree_code code = gimple_assign_rhs_code (stmt);
+ if (code == EQ_EXPR || code == NE_EXPR)
+ {
+ tree rhs1 = gimple_assign_rhs1 (stmt);
+ tree rhs2 = gimple_assign_rhs2 (stmt);
+ if (TREE_CODE (rhs1) == SSA_NAME
+ && TREE_CODE (rhs2) == SSA_NAME)
+ {
+ gcall *call_stmt = dyn_cast<gcall *> (SSA_NAME_DEF_STMT
(rhs1));
+ if (!call_stmt)
+ {
+ call_stmt = dyn_cast<gcall *> (SSA_NAME_DEF_STMT (rhs2));
+ tree tmp = rhs1;
+ rhs1 = rhs2;
+ rhs2 = tmp;
+ }
+
+ tree call_lhs;
+ if (call_stmt
+ && gimple_call_builtin_p (call_stmt, BUILT_IN_STRSTR)
+ && (call_lhs = gimple_call_lhs (call_stmt))
+ && has_single_use (call_lhs))
+ {
+ tree arg0 = gimple_call_arg (call_stmt, 0);
+ if (operand_equal_p (arg0, rhs2, 0))
+ {
+ tree arg1 = gimple_call_arg (call_stmt, 1);
+ tree arg1_len = NULL_TREE;
+ int idx = get_stridx (arg1);
+
+ if (idx)
+ {
+ if (idx < 0)
+ arg1_len = build_int_cst (size_type_node,
+ ~idx);
+ else
+ {
+ strinfo *si = get_strinfo (idx);
+ if (si)
+ arg1_len = get_string_length (si);
+ }
+ }
+
+ if (arg1_len == NULL_TREE)
+ {
+ gimple_stmt_iterator gsi;
+ tree strlen_decl;
+ gimple *strlen_call;
+
+ strlen_decl = builtin_decl_explicit
(BUILT_IN_STRLEN);
+ strlen_call = gimple_build_call (strlen_decl, 1,
+ arg1);
+ arg1_len = make_ssa_name (size_type_node);
+ gimple_call_set_lhs (strlen_call, arg1_len);
+ update_stmt (strlen_call);
+ gsi = gsi_for_stmt (call_stmt);
+ gsi_insert_before (&gsi, strlen_call,
GSI_SAME_STMT);
+ }
+
+ gimple_stmt_iterator gsi = gsi_for_stmt (call_stmt);
+ tree memcmp_decl = builtin_decl_explicit
(BUILT_IN_MEMCMP);
+ gcall *memcmp_call
+ = gimple_build_call (memcmp_decl, 3, arg0, arg1,
+ arg1_len);
+ tree memcmp_lhs = make_ssa_name (integer_type_node);
+ gimple_call_set_lhs (memcmp_call, memcmp_lhs);
+ update_stmt (memcmp_call);
+ gsi_remove (&gsi, true);
+ gsi_insert_before (&gsi, memcmp_call, GSI_SAME_STMT);
+
+ gsi = gsi_for_stmt (stmt);
+ tree zero = build_zero_cst (TREE_TYPE (memcmp_lhs));
+ gassign *ga = gimple_build_assign (lhs, code,
+ memcmp_lhs, zero);
+ gsi_replace (&gsi, ga, false);
+ update_ssa (TODO_update_ssa);
+ }
+ }
+ }
+ }
+ }
+ else if (TREE_CODE (lhs) != SSA_NAME && !TREE_SIDE_EFFECTS (lhs))
{
tree type = TREE_TYPE (lhs);
if (TREE_CODE (type) == ARRAY_TYPE)
