re PR tree-optimization/82493 (UBSAN in gcc/sbitmap.c:368:28: runtime error: shift...

	PR tree-optimization/82493
	* sbitmap.c (bitmap_bit_in_range_p): Fix the implementation.
	(test_range_functions): New function.
	(sbitmap_c_tests): Likewise.
	* selftest-run-tests.c (selftest::run_tests): Run new tests.
	* selftest.h (sbitmap_c_tests): New function.

	* tree-ssa-dse.c (live_bytes_read): Fix thinko.

From-SVN: r253699

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 20fb303d03a574e80efa104c0363139eb0ef2014..b5981edddc4b52dc116e4749a7fdbdc7ac66c340 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2017-10-12  Martin Liska  <mliska@suse.cz>
+
+       PR tree-optimization/82493
+       * sbitmap.c (bitmap_bit_in_range_p): Fix the implementation.
+       (test_range_functions): New function.
+       (sbitmap_c_tests): Likewise.
+       * selftest-run-tests.c (selftest::run_tests): Run new tests.
+       * selftest.h (sbitmap_c_tests): New function.
+
+       * tree-ssa-dse.c (live_bytes_read): Fix thinko.
+
 2017-10-12  Michael Meissner  <meissner@linux.vnet.ibm.com>
 
        * config/rs6000/amo.h: Fix spacing issue.

diff --git a/gcc/sbitmap.c b/gcc/sbitmap.c
index 4bf13a11a1d2070ebf924f2ec7850d9da99a0c59..baef4d05f0d33ada852d1f8d9cc9bcea130dd3ca 100644 (file)
--- a/gcc/sbitmap.c
+++ b/gcc/sbitmap.c
@@ -21,6 +21,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "system.h"
 #include "coretypes.h"
 #include "sbitmap.h"
+#include "selftest.h"
 
 typedef SBITMAP_ELT_TYPE *sbitmap_ptr;
 typedef const SBITMAP_ELT_TYPE *const_sbitmap_ptr;
@@ -322,29 +323,22 @@ bitmap_set_range (sbitmap bmap, unsigned int start, unsigned int count)
 bool
 bitmap_bit_in_range_p (const_sbitmap bmap, unsigned int start, unsigned int end)
 {
+  gcc_checking_assert (start <= end);
   unsigned int start_word = start / SBITMAP_ELT_BITS;
   unsigned int start_bitno = start % SBITMAP_ELT_BITS;
 
-  /* Testing within a word, starting at the beginning of a word.  */
-  if (start_bitno == 0 && (end - start) < SBITMAP_ELT_BITS)
-    {
-      SBITMAP_ELT_TYPE mask = ((SBITMAP_ELT_TYPE)1 << (end - start)) - 1;
-      return (bmap->elms[start_word] & mask) != 0;
-    }
-
   unsigned int end_word = end / SBITMAP_ELT_BITS;
   unsigned int end_bitno = end % SBITMAP_ELT_BITS;
 
-  /* Testing starts somewhere in the middle of a word.  Test up to the
-     end of the word or the end of the requested region, whichever comes
-     first.  */
+  /* Check beginning of first word if different from zero.  */
   if (start_bitno != 0)
     {
-      unsigned int nbits = ((start_word == end_word)
-                           ? end_bitno - start_bitno
-                           : SBITMAP_ELT_BITS - start_bitno);
-      SBITMAP_ELT_TYPE mask = ((SBITMAP_ELT_TYPE)1 << nbits) - 1;
-      mask <<= start_bitno;
+      SBITMAP_ELT_TYPE high_mask = ~(SBITMAP_ELT_TYPE)0;
+      if (start_word == end_word && end_bitno + 1 < SBITMAP_ELT_BITS)
+       high_mask = ((SBITMAP_ELT_TYPE)1 << (end_bitno + 1)) - 1;
+
+      SBITMAP_ELT_TYPE low_mask = ((SBITMAP_ELT_TYPE)1 << start_bitno) - 1;
+      SBITMAP_ELT_TYPE mask = high_mask - low_mask;
       if (bmap->elms[start_word] & mask)
        return true;
       start_word++;
@@ -364,8 +358,9 @@ bitmap_bit_in_range_p (const_sbitmap bmap, unsigned int start, unsigned int end)
     }
 
   /* Now handle residuals in the last word.  */
-  SBITMAP_ELT_TYPE mask
-    = ((SBITMAP_ELT_TYPE)1 << (SBITMAP_ELT_BITS - end_bitno)) - 1;
+  SBITMAP_ELT_TYPE mask = ~(SBITMAP_ELT_TYPE)0;
+  if (end_bitno + 1 < SBITMAP_ELT_BITS)
+    mask = ((SBITMAP_ELT_TYPE)1 << (end_bitno + 1)) - 1;
   return (bmap->elms[start_word] & mask) != 0;
 }
 
@@ -821,3 +816,92 @@ dump_bitmap_vector (FILE *file, const char *title, const char *subtitle,
 
   fprintf (file, "\n");
 }
+
+#if CHECKING_P
+
+namespace selftest {
+
+/* Selftests for sbitmaps.  */
+
+
+/* Verify range functions for sbitmap.  */
+
+static void
+test_range_functions ()
+{
+  sbitmap s = sbitmap_alloc (1024);
+  bitmap_clear (s);
+
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 512, 1023));
+  bitmap_set_bit (s, 100);
+
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 512, 1023));
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 99));
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 101, 1023));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 1, 100));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 64, 100));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 100, 100));
+  ASSERT_TRUE (bitmap_bit_p (s, 100));
+
+  s = sbitmap_alloc (64);
+  bitmap_clear (s);
+  bitmap_set_bit (s, 63);
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 63));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 1, 63));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 63, 63));
+  ASSERT_TRUE (bitmap_bit_p (s, 63));
+
+  s = sbitmap_alloc (1024);
+  bitmap_clear (s);
+  bitmap_set_bit (s, 128);
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 127));
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 129, 1023));
+
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 128));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 1, 128));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 128, 255));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 128, 254));
+  ASSERT_TRUE (bitmap_bit_p (s, 128));
+
+  bitmap_clear (s);
+  bitmap_set_bit (s, 8);
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 8));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 12));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 63));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 127));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 512));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 8, 8));
+  ASSERT_TRUE (bitmap_bit_p (s, 8));
+
+  bitmap_clear (s);
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 0));
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 8));
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 63));
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 1, 63));
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 256));
+
+  bitmap_set_bit (s, 0);
+  bitmap_set_bit (s, 16);
+  bitmap_set_bit (s, 32);
+  bitmap_set_bit (s, 48);
+  bitmap_set_bit (s, 64);
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 0));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 1, 16));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 48, 63));
+  ASSERT_TRUE (bitmap_bit_in_range_p (s, 64, 64));
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 1, 15));
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 17, 31));
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 49, 63));
+  ASSERT_FALSE (bitmap_bit_in_range_p (s, 65, 1023));
+}
+
+/* Run all of the selftests within this file.  */
+
+void
+sbitmap_c_tests ()
+{
+  test_range_functions ();
+}
+
+} // namespace selftest
+#endif /* CHECKING_P */

diff --git a/gcc/selftest-run-tests.c b/gcc/selftest-run-tests.c
index 30e476d14c5da02d2e2873accf1c358d04e06a63..5c84f3a0737c3e7b30a79fcb170eac74efbb26af 100644 (file)
--- a/gcc/selftest-run-tests.c
+++ b/gcc/selftest-run-tests.c
@@ -56,6 +56,7 @@ selftest::run_tests ()
 
   /* Low-level data structures.  */
   bitmap_c_tests ();
+  sbitmap_c_tests ();
   et_forest_c_tests ();
   hash_map_tests_c_tests ();
   hash_set_tests_c_tests ();

diff --git a/gcc/selftest.h b/gcc/selftest.h
index 0572fefd2812159d6a3083a995d5f0d4963f81e8..2e649a70b9e293a360a5418fde7c44b5c6e7c4c0 100644 (file)
--- a/gcc/selftest.h
+++ b/gcc/selftest.h
@@ -171,6 +171,7 @@ extern const char *path_to_selftest_files;
 /* Declarations for specific families of tests (by source file), in
    alphabetical order.  */
 extern void bitmap_c_tests ();
+extern void sbitmap_c_tests ();
 extern void diagnostic_c_tests ();
 extern void diagnostic_show_locus_c_tests ();
 extern void edit_context_c_tests ();

diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c
index 87e2fce9ac5ae0983658e0a6c39c2492f9f978ff..9d6cb146436729bf54b28d08fba0a4ef8911ebe3 100644 (file)
--- a/gcc/tree-ssa-dse.c
+++ b/gcc/tree-ssa-dse.c
@@ -493,7 +493,7 @@ live_bytes_read (ao_ref use_ref, ao_ref *ref, sbitmap live)
 
       /* Now check if any of the remaining bits in use_ref are set in LIVE.  */
       unsigned int start = (use_ref.offset - ref->offset) / BITS_PER_UNIT;
-      unsigned int end  = (use_ref.offset + use_ref.size) / BITS_PER_UNIT;
+      unsigned int end  = ((use_ref.offset + use_ref.size) / BITS_PER_UNIT) - 1;
       return bitmap_bit_in_range_p (live, start, end);
     }
   return true;