common.opt: Add -foptimize-strlen option.

	* common.opt: Add -foptimize-strlen option.
	* Makefile.in (OBJS): Add tree-ssa-strlen.o.
	(tree-sssa-strlen.o): Add dependencies.
	* opts.c (default_options_table): Enable -foptimize-strlen
	by default at -O2 if not -Os.
	* passes.c (init_optimization_passes): Add pass_strlen
	after pass_object_sizes.
	* timevar.def (TV_TREE_STRLEN): New timevar.
	* params.def (PARAM_MAX_TRACKED_STRLENS): New parameter.
	* tree-pass.h (pass_strlen): Declare.
	* tree-ssa-strlen.c: New file.
	* c-decl.c (merge_decls): If compatible stpcpy prototype
	is seen, set implicit_built_in_decls[BUILT_IN_STPCPY].
cp/
	* decl.c (duplicate_decls): If compatible stpcpy prototype
	is seen, set implicit_built_in_decls[BUILT_IN_STPCPY].
testsuite/
	* gcc.dg/strlenopt-1.c: New test.
	* gcc.dg/strlenopt-1f.c: New test.
	* gcc.dg/strlenopt-2.c: New test.
	* gcc.dg/strlenopt-2f.c: New test.
	* gcc.dg/strlenopt-3.c: New test.
	* gcc.dg/strlenopt-4.c: New test.
	* gcc.dg/strlenopt-4g.c: New test.
	* gcc.dg/strlenopt-4gf.c: New test.
	* gcc.dg/strlenopt-5.c: New test.
	* gcc.dg/strlenopt-6.c: New test.
	* gcc.dg/strlenopt-7.c: New test.
	* gcc.dg/strlenopt-8.c: New test.
	* gcc.dg/strlenopt-9.c: New test.
	* gcc.dg/strlenopt-10.c: New test.
	* gcc.dg/strlenopt-11.c: New test.
	* gcc.dg/strlenopt-12.c: New test.
	* gcc.dg/strlenopt-12g.c: New test.
	* gcc.dg/strlenopt-13.c: New test.
	* gcc.dg/strlenopt-14g.c: New test.
	* gcc.dg/strlenopt-14gf.c: New test.
	* gcc.dg/strlenopt-15.c: New test.
	* gcc.dg/strlenopt-16g.c: New test.
	* gcc.dg/strlenopt-17g.c: New test.
	* gcc.dg/strlenopt-18g.c: New test.
	* gcc.dg/strlenopt.h: New file.

From-SVN: r179277

1 files changed, 95 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/strlenopt-20.c b/gcc/testsuite/gcc.dg/strlenopt-20.c
new file mode 100644
index 00000000000..6fe99a422e9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strlenopt-20.c
@@ -0,0 +1,95 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-strlen" } */
+
+#include "strlenopt.h"
+
+__attribute__((noinline, noclone)) const char *
+fn1 (int x, int y)
+{
+  const char *p;
+  switch (x)
+    {
+    case 0:
+      p = "abcd";
+      /* Prevent cswitch optimization.  */
+      asm volatile ("" : : : "memory");
+      break;
+    case 1:
+      p = "efgh";
+      break;
+    case 2:
+      p = "ijkl";
+      break;
+    default:
+      p = "mnop";
+      break;
+    }
+  if (y)
+    /* strchr should be optimized into p + 4 here.  */
+    return strchr (p, '\0');
+  else
+    /* and strlen into 3.  */
+    return p + strlen (p + 1);
+}
+
+__attribute__((noinline, noclone)) size_t
+fn2 (char *p, char *q)
+{
+  size_t l;
+  /* Both strcpy calls can be optimized into memcpy, strlen needs to stay.  */
+  strcpy (p, "abc");
+  p[3] = 'd';
+  l = strlen (p);
+  strcpy (q, p);
+  return l;
+}
+
+__attribute__((noinline, noclone)) char *
+fn3 (char *p)
+{
+  char *c;
+  /* The strcpy call can be optimized into memcpy, strchr needs to stay,
+     strcat is optimized into memcpy.  */
+  strcpy (p, "abc");
+  p[3] = 'd';
+  c = strchr (p, '\0');
+  strcat (p, "efgh");
+  return c;
+}
+
+int
+main ()
+{
+  int i;
+  char buf[64], buf2[64];
+  for (i = 0; i < 5; i++)
+    {
+      const char *p = "abcdefghijklmnop" + (i < 3 ? i : 3) * 4;
+      const char *q;
+      q = fn1 (i, 1);
+      if (memcmp (q - 4, p, 4) != 0 || q[0] != '\0')
+	abort ();
+      q = fn1 (i, 0);
+      if (memcmp (q - 3, p, 4) != 0 || q[1] != '\0')
+	abort ();
+    }
+  memset (buf, '\0', sizeof buf);
+  memset (buf + 4, 'z', 2);
+  if (fn2 (buf, buf2) != 6
+      || memcmp (buf, "abcdzz", 7) != 0
+      || memcmp (buf2, "abcdzz", 7) != 0)
+    abort ();
+  memset (buf, '\0', sizeof buf);
+  memset (buf + 4, 'z', 2);
+  if (fn3 (buf) != buf + 6 || memcmp (buf, "abcdzzefgh", 11) != 0)
+    abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "strlen \\(" 1 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "memcpy \\(" 4 "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" } } */