re PR middle-end/83477 (Wrong code w/ -O1)

	PR tree-optimization/83477
	* tree-ssa-threadedge.c (record_temporary_equivalences_from_phis): For
	a non-virtual PHI, always push a new range.

	PR tree-optimization/83477
	* gcc.c-torture/execute/pr83477.c: New test.

From-SVN: r255837

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4581f41d8fb242e2eee629d17f8a0771c8191ff2..8a80f18045baf522a21e7b04f735f686b256680b 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-12-18  Jeff Law  <law@redhat.com>
+
+       PR tree-optimization/83477
+       * tree-ssa-threadedge.c (record_temporary_equivalences_from_phis): For
+       a non-virtual PHI, always push a new range.
+
 2017-12-19  Martin Sebor  <msebor@redhat.com>
 
        PR middle-end/77608
@@ -195,7 +201,6 @@
        * tree-ssa-dom.c (record_equivalences_from_phis): Fix handling
        of degenerates resulting from ignoring an edge.
 
->>>>>>> .r255835
 2017-12-18  Martin Sebor  <msebor@redhat.com>
 
        PR middle-end/83373

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 63d671374e3bf219cada1986a0948036c91aa546..b32cb7a09faf250bf58a6fa2a8110e92dc493db9 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-12-18  Jeff Law  <law@redhat.com>
+
+       PR tree-optimization/83477
+       * gcc.c-torture/execute/pr83477.c: New test.
+
 2017-12-19  Martin Sebor  <msebor@redhat.com>
 
        PR middle-end/77608
@@ -63,7 +68,6 @@
        PR ipa/83346
        * g++.dg/ipa/pr82801.C: New test.
 
->>>>>>> .r255835
 2017-12-18  Martin Sebor  <msebor@redhat.com>
 
        PR middle-end/83373

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr83477.c b/gcc/testsuite/gcc.c-torture/execute/pr83477.c
new file mode 100644 (file)
index 0000000..de667fd
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr83477.c
@@ -0,0 +1,22 @@
+int yf = 0;
+
+void
+pl (int q5, int nd)
+{
+  unsigned int hp = q5;
+  int zx = (q5 == 0) ? hp : (hp / q5);
+
+  yf = ((nd < 2) * zx != 0) ? nd : 0;
+}
+
+int
+main (void)
+{
+  pl (1, !yf);
+  if (yf != 1)
+    __builtin_abort ();
+
+  return 0;
+}
+
+

diff --git a/gcc/tree-ssa-threadedge.c b/gcc/tree-ssa-threadedge.c
index 1fafd7b593257991ab32bee7b1bb27eb860eae21..0c782f5169794ec4e0f4a38b08e3a129e509c3cf 100644 (file)
--- a/gcc/tree-ssa-threadedge.c
+++ b/gcc/tree-ssa-threadedge.c
@@ -156,11 +156,37 @@ record_temporary_equivalences_from_phis (edge e,
       const_and_copies->record_const_or_copy (dst, src);
 
       /* Also update the value range associated with DST, using
-        the range from SRC.  */
-      if (evrp_range_analyzer && TREE_CODE (src) == SSA_NAME)
+        the range from SRC.
+
+        Note that even if SRC is a constant we need to set a suitable
+        output range so that VR_UNDEFINED ranges do not leak through.  */
+      if (evrp_range_analyzer)
        {
-         value_range *vr = evrp_range_analyzer->get_value_range (src);
-         evrp_range_analyzer->push_value_range (dst, vr);
+         /* Get an empty new VR we can pass to update_value_range and save
+            away in the VR stack.  */
+         vr_values *vr_values = evrp_range_analyzer->get_vr_values ();
+         value_range *new_vr = vr_values->allocate_value_range ();
+         memset (new_vr, 0, sizeof (value_range));
+
+         /* There are three cases to consider:
+
+              First if SRC is an SSA_NAME, then we can copy the value
+              range from SRC into NEW_VR.
+
+              Second if SRC is an INTEGER_CST, then we can just wet
+              NEW_VR to a singleton range.
+
+              Otherwise set NEW_VR to varying.  This may be overly
+              conservative.  */
+         if (TREE_CODE (src) == SSA_NAME)
+           copy_value_range (new_vr, vr_values->get_value_range (src));
+         else if (TREE_CODE (src) == INTEGER_CST)
+           set_value_range_to_value (new_vr, src,  NULL);
+         else
+           set_value_range_to_varying (new_vr);
+
+         /* This is a temporary range for DST, so push it.  */
+         evrp_range_analyzer->push_value_range (dst, new_vr);
        }
     }
   return true;