* tree-ssa-structalias.c (find_func_aliases_for_builtin_call): Handle

	BUILT_IN_STRDUP and BUILT_IN_STRNDUP.
	* tree-ssa-alias.c (call_may_clobber_ref_p_1): Likewise.  Fix
	handling of BUILT_IN_STRNCAT and BUILT_IN_STRNCAT_CHK.
	(ref_maybe_used_by_call_p_1): Fix handling of BUILT_IN_STRCAT,
	BUILT_IN_STRNCAT, BUILT_IN_STRCAT_CHK and BUILT_IN_STRNCAT_CHK.

	* gcc.dg/strlenopt-21.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@179387 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 150 insertions, 8 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 52d80822bac..525ca80ba6b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2011-09-30  Jakub Jelinek  <jakub@redhat.com>
+	    Richard Guenther  <rguenther@suse.de>
+
+	* tree-ssa-structalias.c (find_func_aliases_for_builtin_call): Handle
+	BUILT_IN_STRDUP and BUILT_IN_STRNDUP.
+	* tree-ssa-alias.c (call_may_clobber_ref_p_1): Likewise.  Fix
+	handling of BUILT_IN_STRNCAT and BUILT_IN_STRNCAT_CHK.
+	(ref_maybe_used_by_call_p_1): Fix handling of BUILT_IN_STRCAT,
+	BUILT_IN_STRNCAT, BUILT_IN_STRCAT_CHK and BUILT_IN_STRNCAT_CHK.
+
 2011-09-30  Jan Beulich  <jbeulich@suse.com>
 
 	* lto-cgraph.c (output_cgraph): Remove processing of
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0b1e69f154e..2d8e0664f1c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2011-09-30  Jakub Jelinek  <jakub@redhat.com>
+
+	* gcc.dg/strlenopt-21.c: New test.
+
 2011-09-30  Revital Eres  <revital.eres@linaro.org>
 
 	* gcc.dg/sms-10.c: New file
diff --git a/gcc/testsuite/gcc.dg/strlenopt-21.c b/gcc/testsuite/gcc.dg/strlenopt-21.c
new file mode 100644
index 00000000000..cd5fc5d928f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strlenopt-21.c
@@ -0,0 +1,66 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-strlen -fdump-tree-optimized" } */
+
+#include "strlenopt.h"
+
+struct S { char *p; size_t l; };
+
+__attribute__((noinline, noclone)) struct S
+foo (char *x, int n)
+{
+  int i;
+  char a[64];
+  char *p = strchr (x, '\0');
+  struct S s;
+  /* strcpy here is optimized into memcpy, length computed as p - x + 1.  */
+  strcpy (a, x);
+  /* strcat here is optimized into memcpy.  */
+  strcat (p, "abcd");
+  for (i = 0; i < n; i++)
+    if ((i % 123) == 53)
+      /* strcat here is optimized into strlen and memcpy.  */
+      strcat (a, "efg");
+  s.p = strdup (a);
+  /* The strlen should be optimized here into 4.  */
+  s.l = strlen (p);
+  return s;
+}
+
+int
+main ()
+{
+  char buf[32];
+  struct S s;
+  buf[0] = 'z';
+  buf[1] = '\0';
+  s = foo (buf, 0);
+  if (s.l != 4 || memcmp (buf, "zabcd", 6) != 0)
+    abort ();
+  if (s.p == NULL)
+    return 0;
+  if (memcmp (s.p, "z", 2) != 0)
+    abort ();
+  s = foo (buf, 60);
+  if (s.l != 4 || memcmp (buf, "zabcdabcd", 10) != 0)
+    abort ();
+  if (s.p == NULL)
+    return 0;
+  if (memcmp (s.p, "zabcdefg", 9) != 0)
+    abort ();
+  s = foo (buf, 240);
+  if (s.l != 4 || memcmp (buf, "zabcdabcdabcd", 14) != 0)
+    abort ();
+  if (s.p == NULL)
+    return 0;
+  if (memcmp (s.p, "zabcdabcdefgefg", 16) != 0)
+    abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "strlen \\(" 1 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "memcpy \\(" 3 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strcpy \\(" 0 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strcat \\(" 0 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strchr \\(" 1 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "stpcpy \\(" 0 "strlen" } } */
+/* { dg-final { cleanup-tree-dump "strlen" } } */
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 10c529b114f..82307decaf4 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -1178,8 +1178,20 @@ ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref)
       && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
     switch (DECL_FUNCTION_CODE (callee))
       {
-	/* All the following functions clobber memory pointed to by
-	   their first argument.  */
+	/* All the following functions read memory pointed to by
+	   their second argument.  strcat/strncat additionally
+	   reads memory pointed to by the first argument.  */
+	case BUILT_IN_STRCAT:
+	case BUILT_IN_STRNCAT:
+	  {
+	    ao_ref dref;
+	    ao_ref_init_from_ptr_and_size (&dref,
+					   gimple_call_arg (call, 0),
+					   NULL_TREE);
+	    if (refs_may_alias_p_1 (&dref, ref, false))
+	      return true;
+	  }
+	  /* FALLTHRU */
 	case BUILT_IN_STRCPY:
 	case BUILT_IN_STRNCPY:
 	case BUILT_IN_MEMCPY:
@@ -1187,8 +1199,6 @@ ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref)
 	case BUILT_IN_MEMPCPY:
 	case BUILT_IN_STPCPY:
 	case BUILT_IN_STPNCPY:
-	case BUILT_IN_STRCAT:
-	case BUILT_IN_STRNCAT:
 	  {
 	    ao_ref dref;
 	    tree size = NULL_TREE;
@@ -1199,14 +1209,23 @@ ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref)
 					   size);
 	    return refs_may_alias_p_1 (&dref, ref, false);
 	  }
+	case BUILT_IN_STRCAT_CHK:
+	case BUILT_IN_STRNCAT_CHK:
+	  {
+	    ao_ref dref;
+	    ao_ref_init_from_ptr_and_size (&dref,
+					   gimple_call_arg (call, 0),
+					   NULL_TREE);
+	    if (refs_may_alias_p_1 (&dref, ref, false))
+	      return true;
+	  }
+	  /* FALLTHRU */
 	case BUILT_IN_STRCPY_CHK:
 	case BUILT_IN_STRNCPY_CHK:
 	case BUILT_IN_MEMCPY_CHK:
 	case BUILT_IN_MEMMOVE_CHK:
 	case BUILT_IN_MEMPCPY_CHK:
 	case BUILT_IN_STPCPY_CHK:
-	case BUILT_IN_STRCAT_CHK:
-	case BUILT_IN_STRNCAT_CHK:
 	  {
 	    ao_ref dref;
 	    tree size = NULL_TREE;
@@ -1226,6 +1245,19 @@ ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref)
 					   size);
 	    return refs_may_alias_p_1 (&dref, ref, false);
 	  }
+	/* These read memory pointed to by the first argument.  */
+	case BUILT_IN_STRDUP:
+	case BUILT_IN_STRNDUP:
+	  {
+	    ao_ref dref;
+	    tree size = NULL_TREE;
+	    if (gimple_call_num_args (call) == 2)
+	      size = gimple_call_arg (call, 1);
+	    ao_ref_init_from_ptr_and_size (&dref,
+					   gimple_call_arg (call, 0),
+					   size);
+	    return refs_may_alias_p_1 (&dref, ref, false);
+	  }
 	/* The following builtins do not read from memory.  */
 	case BUILT_IN_FREE:
 	case BUILT_IN_MALLOC:
@@ -1467,7 +1499,12 @@ call_may_clobber_ref_p_1 (gimple call, ao_ref *ref)
 	  {
 	    ao_ref dref;
 	    tree size = NULL_TREE;
-	    if (gimple_call_num_args (call) == 3)
+	    /* Don't pass in size for strncat, as the maximum size
+	       is strlen (dest) + n + 1 instead of n, resp.
+	       n + 1 at dest + strlen (dest), but strlen (dest) isn't
+	       known.  */
+	    if (gimple_call_num_args (call) == 3
+		&& DECL_FUNCTION_CODE (callee) != BUILT_IN_STRNCAT)
 	      size = gimple_call_arg (call, 2);
 	    ao_ref_init_from_ptr_and_size (&dref,
 					   gimple_call_arg (call, 0),
@@ -1486,7 +1523,12 @@ call_may_clobber_ref_p_1 (gimple call, ao_ref *ref)
 	  {
 	    ao_ref dref;
 	    tree size = NULL_TREE;
-	    if (gimple_call_num_args (call) == 4)
+	    /* Don't pass in size for __strncat_chk, as the maximum size
+	       is strlen (dest) + n + 1 instead of n, resp.
+	       n + 1 at dest + strlen (dest), but strlen (dest) isn't
+	       known.  */
+	    if (gimple_call_num_args (call) == 4
+		&& DECL_FUNCTION_CODE (callee) != BUILT_IN_STRNCAT_CHK)
 	      size = gimple_call_arg (call, 2);
 	    ao_ref_init_from_ptr_and_size (&dref,
 					   gimple_call_arg (call, 0),
@@ -1506,6 +1548,8 @@ call_may_clobber_ref_p_1 (gimple call, ao_ref *ref)
 	   being the definition point for the pointer.  */
 	case BUILT_IN_MALLOC:
 	case BUILT_IN_CALLOC:
+	case BUILT_IN_STRDUP:
+	case BUILT_IN_STRNDUP:
 	  /* Unix98 specifies that errno is set on allocation failure.  */
 	  if (flag_errno_math
 	      && targetm.ref_may_alias_errno (ref))
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 1023acfab19..821fc7d92b2 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -4130,6 +4130,24 @@ find_func_aliases_for_builtin_call (gimple t)
       case BUILT_IN_REMQUOL:
       case BUILT_IN_FREE:
 	return true;
+      case BUILT_IN_STRDUP:
+      case BUILT_IN_STRNDUP:
+	if (gimple_call_lhs (t))
+	  {
+	    handle_lhs_call (t, gimple_call_lhs (t), gimple_call_flags (t),
+			     NULL, fndecl);
+	    get_constraint_for_ptr_offset (gimple_call_lhs (t),
+					   NULL_TREE, &lhsc);
+	    get_constraint_for_ptr_offset (gimple_call_arg (t, 0),
+					   NULL_TREE, &rhsc);
+	    do_deref (&lhsc);
+	    do_deref (&rhsc);
+	    process_all_all_constraints (lhsc, rhsc);
+	    VEC_free (ce_s, heap, lhsc);
+	    VEC_free (ce_s, heap, rhsc);
+	    return true;
+	  }
+	break;
       /* Trampolines are special - they set up passing the static
 	 frame.  */
       case BUILT_IN_INIT_TRAMPOLINE: