tree-optimization/111397 - missed copy propagation involving abnormal dest

The following extends the previous enhancement to copy propagation
involving abnormals.  We can easily replace abnormal uses by not
abnormal uses and only need to preserve the abnormals in PHI arguments
flowing in from abnormal edges.  This changes the may_propagate_copy
argument indicating we are not propagating into a PHI node to indicate
whether we know we are not propagating into a PHI argument from an
abnormal PHI instead.

	PR tree-optimization/111397
	* tree-ssa-propagate.cc (may_propagate_copy): Change optional
	argument to specify whether the PHI destination doesn't flow in
	from an abnormal PHI.
	(propagate_value): Adjust.
	* tree-ssa-forwprop.cc (pass_forwprop::execute): Indicate abnormal
	PHI dest.
	* tree-ssa-sccvn.cc (eliminate_dom_walker::before_dom_children):
	Likewise.
	(process_bb): Likewise.

	* gcc.dg/uninit-pr111397.c: New testcase.

diff --git a/gcc/testsuite/gcc.dg/uninit-pr111397.c b/gcc/testsuite/gcc.dg/uninit-pr111397.c
new file mode 100644 (file)
index 0000000..ec12f9d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/uninit-pr111397.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wuninitialized" } */
+
+int globalVar = 1;
+int __attribute__ ((__returns_twice__)) test_setjmpex(void *context);
+
+void testfn()
+{
+  int localVar = globalVar;
+  while (!localVar) {
+      test_setjmpex(__builtin_frame_address (0)); // { dg-bogus "uninitialized" }
+      if (globalVar)
+       break;
+  }
+}

diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
index 047f9237dd4158669e484f6bcb6ec74c045faebe..94ca47a9726da2e7492848c82a306be09a9ec412 100644 (file)
--- a/gcc/tree-ssa-forwprop.cc
+++ b/gcc/tree-ssa-forwprop.cc
@@ -4070,7 +4070,7 @@ pass_forwprop::execute (function *fun)
              continue;
            tree val = fwprop_ssa_val (arg);
            if (val != arg
-               && may_propagate_copy (arg, val))
+               && may_propagate_copy (arg, val, !(e->flags & EDGE_ABNORMAL)))
              propagate_value (use_p, val);
          }
 

diff --git a/gcc/tree-ssa-propagate.cc b/gcc/tree-ssa-propagate.cc
index cb68b419b8ce03eec3afa0624768e92f96497f2a..a29c49328ad1a271a87e4103e97e0305a9fdcf14 100644 (file)
--- a/gcc/tree-ssa-propagate.cc
+++ b/gcc/tree-ssa-propagate.cc
@@ -1032,11 +1032,12 @@ substitute_and_fold_engine::substitute_and_fold (basic_block block)
 
 
 /* Return true if we may propagate ORIG into DEST, false otherwise.
-   If DEST_NOT_PHI_ARG_P is true then assume the propagation does
-   not happen into a PHI argument which relaxes some constraints.  */
+   If DEST_NOT_ABNORMAL_PHI_EDGE_P is true then assume the propagation does
+   not happen into a PHI argument which flows in from an abnormal edge
+   which relaxes some constraints.  */
 
 bool
-may_propagate_copy (tree dest, tree orig, bool dest_not_phi_arg_p)
+may_propagate_copy (tree dest, tree orig, bool dest_not_abnormal_phi_edge_p)
 {
   tree type_d = TREE_TYPE (dest);
   tree type_o = TREE_TYPE (orig);
@@ -1056,9 +1057,9 @@ may_propagate_copy (tree dest, tree orig, bool dest_not_phi_arg_p)
           && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig))
     return false;
   /* Similarly if DEST flows in from an abnormal edge then the copy cannot be
-     propagated.  If we know we do not propagate into a PHI argument this
+     propagated.  If we know we do not propagate into such a PHI argument this
      does not apply.  */
-  else if (!dest_not_phi_arg_p
+  else if (!dest_not_abnormal_phi_edge_p
           && TREE_CODE (dest) == SSA_NAME
           && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (dest))
     return false;
@@ -1162,8 +1163,13 @@ void
 propagate_value (use_operand_p op_p, tree val)
 {
   if (flag_checking)
-    gcc_assert (may_propagate_copy (USE_FROM_PTR (op_p), val,
-                                   !is_a <gphi *> (USE_STMT (op_p))));
+    {
+      bool ab = (is_a <gphi *> (USE_STMT (op_p))
+                && (gimple_phi_arg_edge (as_a <gphi *> (USE_STMT (op_p)),
+                                         PHI_ARG_INDEX_FROM_USE (op_p))
+                    ->flags & EDGE_ABNORMAL));
+      gcc_assert (may_propagate_copy (USE_FROM_PTR (op_p), val, !ab));
+    }
   replace_exp (op_p, val);
 }
 

diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc
index d9487be302b82ad80db2b09c46e04bf18fdf5e00..1eaf5f6a3633e6091f3783c66495f5477f0fae76 100644 (file)
--- a/gcc/tree-ssa-sccvn.cc
+++ b/gcc/tree-ssa-sccvn.cc
@@ -7399,7 +7399,8 @@ eliminate_dom_walker::before_dom_children (basic_block b)
              || virtual_operand_p (arg))
            continue;
          tree sprime = eliminate_avail (b, arg);
-         if (sprime && may_propagate_copy (arg, sprime))
+         if (sprime && may_propagate_copy (arg, sprime,
+                                           !(e->flags & EDGE_ABNORMAL)))
            propagate_value (use_p, sprime);
        }
 
@@ -8192,7 +8193,7 @@ process_bb (rpo_elim &avail, basic_block bb,
                                            arg);
          if (sprime
              && sprime != arg
-             && may_propagate_copy (arg, sprime))
+             && may_propagate_copy (arg, sprime, !(e->flags & EDGE_ABNORMAL)))
            propagate_value (use_p, sprime);
        }