forwprop: Change an if into an assert

Since the merge of the tuples branch (r0-88576-g726a989a8b74bf), the
if:
```
  if (TREE_CODE_CLASS (gimple_cond_code (stmt)) != tcc_comparison)
```
Will always be false so let's change it into an assert.

gcc/ChangeLog:

	* tree-ssa-forwprop.cc (forward_propagate_into_gimple_cond): Assert
	that gimple_cond_code is always a comparison.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>

diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
index 4ec5b6a6ba1a2fad6e6d86fb019658678e34d49d..60b7c80e07c29507ffd2a255e17dba3198ab5009 100644 (file)
--- a/gcc/tree-ssa-forwprop.cc
+++ b/gcc/tree-ssa-forwprop.cc
@@ -551,9 +551,8 @@ forward_propagate_into_gimple_cond (gcond *stmt)
   tree rhs1 = gimple_cond_lhs (stmt);
   tree rhs2 = gimple_cond_rhs (stmt);
 
-  /* We can do tree combining on SSA_NAME and comparison expressions.  */
-  if (TREE_CODE_CLASS (gimple_cond_code (stmt)) != tcc_comparison)
-    return 0;
+  /* GIMPLE_COND will always be a comparison.  */
+  gcc_assert (TREE_CODE_CLASS (gimple_cond_code (stmt)) == tcc_comparison);
 
   tmp = forward_propagate_into_comparison_1 (stmt, code,
                                             boolean_type_node,