Bring a couple of fixes for gcc optimizations.

The GCC4.3 branch contains some optimization fixes
that were not considered regressions and therefore
were never backported. We are bringing a couple of
them that are under GPLv2 since they were made
before the license switch upstream.

While here, add the GCC revision numbers in the
log.

Discussed with: jkim
MFC after:	1 week

1 files changed, 17 insertions, 0 deletions

diff --git a/contrib/gcc/tree-ssa-pre.c b/contrib/gcc/tree-ssa-pre.c
index 9c7b89f..ba32b3c 100644
--- a/contrib/gcc/tree-ssa-pre.c
+++ b/contrib/gcc/tree-ssa-pre.c
@@ -1076,6 +1076,7 @@ phi_translate (tree expr, value_set_t set, basic_block pred,
 	    tree newexpr;
 	    tree vh = get_value_handle (expr);
 	    bool listchanged = false;
+	    bool invariantarg = false;
 	    VEC (tree, gc) *vuses = VALUE_HANDLE_VUSES (vh);
 	    VEC (tree, gc) *tvuses;
 
@@ -1134,10 +1135,26 @@ phi_translate (tree expr, value_set_t set, basic_block pred,
 		    if (newval != oldval)
 		      {
 			listchanged = true;
+			invariantarg |= is_gimple_min_invariant (newval);
 			TREE_VALUE (newwalker) = get_value_handle (newval);
 		      }
 		  }
 	      }
+
+	    /* In case of new invariant args we might try to fold the call
+	       again.  */
+	    if (invariantarg)
+	      {
+		tree tmp = fold_ternary (CALL_EXPR, TREE_TYPE (expr),
+					 newop0, newarglist, newop2);
+		if (tmp)
+		  {
+		    STRIP_TYPE_NOPS (tmp);
+		    if (is_gimple_min_invariant (tmp))
+		      return tmp;
+		  }
+	      }
+
 	    if (listchanged)
 	      vn_lookup_or_add (newarglist, NULL);