Workaround to silence the clang static analyzer.

diff --git a/ChangeLog b/ChangeLog
index b9f597a22adc03d3e725c48b909fd2e87f14f7a8..8c795096c4e6b01afd43595d8980515b92c5e4e5 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2017-09-14  Niels Möller  <nisse@lysator.liu.se>
+
+       * ecc-mod.c (ecc_mod): Workaround to silence a false positive from
+       the clang static analyzer.
+
 2017-09-12  Niels Möller  <nisse@lysator.liu.se>
 
        * testsuite/testutils.h (mpn_zero_p): Avoid redefining mpn_zero_p

diff --git a/ecc-mod.c b/ecc-mod.c
index 5fee4c68c46c7365ba2b4fd7c4bcbb86443a241e..4e77f0c0e8a88244419704143c73ae2d9148e759 100644 (file)
--- a/ecc-mod.c
+++ b/ecc-mod.c
@@ -51,7 +51,7 @@ ecc_mod (const struct ecc_modulo *m, mp_limb_t *rp)
   mp_size_t i;
   unsigned shift;
 
-  assert (sn > 0);
+  assert (bn < mn);
 
   /* FIXME: Could use mpn_addmul_2. */
   /* Eliminate sn limbs at a time */
@@ -72,6 +72,12 @@ ecc_mod (const struct ecc_modulo *m, mp_limb_t *rp)
     }
   else
     {
+      /* The loop below always runs at least once. But the analyzer
+        doesn't realize that, and complains about hi being used later
+        on without a well defined value. */
+#ifdef __clang_analyzer__
+      hi = 0;
+#endif
       while (rn >= 2 * mn - bn)
        {
          rn -= sn;