[Bug tree-optimization] Fix for PR71994

[kugan]

Hi,

For testcase in pr71994, type of bb conditional result and the type of 
the PHI stmt are different (as om.0_1 is int and the first PHI argument 
is _bool; PHI stmt uses a constant zero that comes from edge 2). 
Therefore when we optimize final range test stmt, we end up setting 
integer 1 for other PHI argument. This results in ICE.

   <bb 2>:
   om.0_1 = om;
   _2 = om.0_1 >= 0;
   int _3 = (int) _2;
   if (om.0_1 != 0)
     goto <bb 3>;
   else
     goto <bb 4>;

   <bb 3>:
   int _4 = om.0_1 & _3;
   _Bool _12 = _4 != 0;
   <bb 4>:

   # _Bool _13 = PHI <0(2), _12(3)>


IMHO, the fix should be that, we should check the type before replacing 
the value (punt otherwise). Attached patch does that. Bootstrapped and 
regression tested on x86_64-linux-gnu with no new regressions. Is this 
OK for trunk?

Thanks,
Kugan

gcc/testsuite/ChangeLog:

2016-07-26  Kugan Vivekanandarajah  <kuganv@linaro.org>

	* gcc.dg/torture/pr71994.c: New test.

gcc/ChangeLog:

2016-07-26  Kugan Vivekanandarajah  <kuganv@linaro.org>

	* tree-ssa-reassoc.c (maybe_optimize_range_tests): Check type 
compatibility.

-------------- next part --------------
diff --git a/gcc/testsuite/gcc.dg/torture/pr71994.c b/gcc/testsuite/gcc.dg/torture/pr71994.c
index e69de29..8f5e92c 100644
--- a/gcc/testsuite/gcc.dg/torture/pr71994.c
+++ b/gcc/testsuite/gcc.dg/torture/pr71994.c
@@ -0,0 +1,14 @@
+/* PR tree-optimization/71994 */
+/* { dg-do compile } */
+int om, h6;
+
+void eo (void)
+{
+  const int tl = 1;
+  int ln;
+
+  h6 = (om + tl) > 0;
+  ln = om && (om & h6);
+  h6 = om;
+  om = ln < h6;
+}
diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index 18cf978..91d7f06 100644
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -3635,8 +3635,15 @@ maybe_optimize_range_tests (gimple *stmt)
 		{
 		  gcc_assert (bb == last_bb);
 		  new_op = ops[bbinfo[idx].first_idx++]->op;
+		  if (!types_compatible_p (TREE_TYPE (new_op),
+					   TREE_TYPE (bbinfo[idx].op))
+		      && TREE_CODE (new_op) == INTEGER_CST)
+		    new_op = fold_convert (TREE_TYPE (bbinfo[idx].op),
+					   new_op);
 		}
-	      if (bbinfo[idx].op != new_op)
+	      if (bbinfo[idx].op != new_op
+		  && types_compatible_p (TREE_TYPE (new_op),
+					 TREE_TYPE (bbinfo[idx].op)))
 		{
 		  imm_use_iterator iter;
 		  use_operand_p use_p;