re PR tree-optimization/65170 (curve25519-donna-c64 miscompilation)

	PR tree-optimization/65170
	* wide-int.cc (wi::mul_internal): For the umul_ppmm optimization,
	if val[1] < 0, clear also val[2] and return 3.

	* gcc.c-torture/execute/pr65170.c: New test.
	* gcc.dg/tree-ssa/vrp96.c: New test.

From-SVN: r220931

5 files changed, 98 insertions, 1 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d039c0a..4bbdfe3 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2015-02-24  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/65170
+	* wide-int.cc (wi::mul_internal): For the umul_ppmm optimization,
+	if val[1] < 0, clear also val[2] and return 3.
+
 2015-02-24  Alan Modra  <amodra@gmail.com>
 
 	PR target/65172
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 11f06fc..daf3e18 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2015-02-24  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/65170
+	* gcc.c-torture/execute/pr65170.c: New test.
+	* gcc.dg/tree-ssa/vrp96.c: New test.
+
 2015-02-24  Tom de Vries  <tom@codesourcery.com>
 
 	* gfortran.dg/readwrite_unf_direct_eor_1.f90: Add missing close.
@@ -27,7 +33,7 @@
 	registers have the right values.  Save register state into
 	static data rather than on the stack.
 
-2015-02-20  Jakub Jelinek  <jakub@redhat.com>
+2015-02-23  Jakub Jelinek  <jakub@redhat.com>
 
 	PR bootstrap/63888
 	* c-c++-common/asan/pr63888.c: New test.
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr65170.c b/gcc/testsuite/gcc.c-torture/execute/pr65170.c
new file mode 100644
index 0000000..60c0052
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr65170.c
@@ -0,0 +1,27 @@
+/* PR tree-optimization/65170 */
+
+#ifdef __SIZEOF_INT128__
+typedef unsigned __int128 V;
+typedef unsigned long long int H;
+#else
+typedef unsigned long long int V;
+typedef unsigned int H;
+#endif
+
+__attribute__((noinline, noclone)) void
+foo (V b, V c)
+{
+  V a;
+  b &= (H) -1;
+  c &= (H) -1;
+  a = b * c;
+  if (a != 1)
+    __builtin_abort ();
+}
+
+int
+main ()
+{
+  foo (1, 1);
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp96.c b/gcc/testsuite/gcc.dg/tree-ssa/vrp96.c
new file mode 100644
index 0000000..e17e424
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp96.c
@@ -0,0 +1,53 @@
+/* PR tree-optimization/65170 */
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-O2 -fdump-tree-vrp1" } */
+
+typedef unsigned __int128 T;
+extern void link_error (void);
+extern void required_check (void);
+
+T
+foo (T b, T c)
+{
+  T a;
+  b &= 0xffffffffffffffffULL;
+  c &= 0xffffffffffffffffULL;
+  if (b < 7 || c < 7)
+    return 0;
+  a = b * c;
+  if (a < 49 || a > (((T) 0xfffffffffffffffeULL << 64) | 1))
+    link_error ();
+  return a;
+}
+
+T
+bar (T b, T c)
+{
+  T a;
+  b &= 0xffffffffffffffffULL;
+  c &= 0xffffffffffffffffULL;
+  if (b < 7 || c < 7)
+    return 0;
+  a = b * c;
+  if (a == 49)
+    required_check ();
+  return a;
+}
+
+T
+baz (T b, T c)
+{
+  T a;
+  b &= 0xffffffffffffffffULL;
+  c &= 0xffffffffffffffffULL;
+  if (b < 7 || c < 7)
+    return 0;
+  a = b * c;
+  if (a == (((T) 0xfffffffffffffffeULL << 64) | 1))
+    required_check ();
+  return a;
+}
+
+/* { dg-final { scan-tree-dump-not "link_error" "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "required_check" 2 "vrp1" } } */
+/* { dg-final { cleanup-tree-dump "vrp1" } } */
diff --git a/gcc/wide-int.cc b/gcc/wide-int.cc
index 7662648..1a7fc14 100644
--- a/gcc/wide-int.cc
+++ b/gcc/wide-int.cc
@@ -1309,6 +1309,11 @@ wi::mul_internal (HOST_WIDE_INT *val, const HOST_WIDE_INT *op1val,
 	      return 1;
 	    }
 	  umul_ppmm (val[1], val[0], op1.ulow (), op2.ulow ());
+	  if (val[1] < 0 && prec > HOST_BITS_PER_WIDE_INT * 2)
+	    {
+	      val[2] = 0;
+	      return 3;
+	    }
 	  return 1 + (val[1] != 0 || val[0] < 0);
 	}
       /* Likewise if the output is a full single HWI, except that the