diff --git a/build/jam/BuildSetup b/build/jam/BuildSetup
index 1896f2a352..efc486cbd5 100644
--- a/build/jam/BuildSetup
+++ b/build/jam/BuildSetup
@@ -156,10 +156,16 @@ if $(HAIKU_USE_GCC_PIPE) = 1 {
 	HAIKU_GCC_BASE_FLAGS = -pipe ;
 }
 
-# disable strict aliasing on anything newer than gcc 2 as it may lead to unexpected results.
-# TODO: remove this when all code has been analyzed/fixed with regard to aliasing.
+# disable strict aliasing on anything newer than gcc 2 as it may lead to
+# unexpected results. also disable the tree-vrp (value range propagation)
+# optimization for now as with the current gcc4 version we are using this
+# results in some broken code.
+# TODO: remove the -fno-strict-aliasing option when all code has been
+#		analyzed/fixed with regard to aliasing.
+# TODO: retest/remove the -fno-tree-vrp option as soon as we have updated our
+#		gcc4 compiler.
 if $(HAIKU_GCC_VERSION[1]) >= 3 {
-	HAIKU_GCC_BASE_FLAGS += -fno-strict-aliasing ;
+	HAIKU_GCC_BASE_FLAGS += -fno-strict-aliasing -fno-tree-vrp ;
 }
 
 # override gcc 2.95.3's header directory -- strictly necessary only when using