* loop-invariant.c: Include target.h.

	(check_dependency): Return false for an uninitialized argument register
	that is likely to be spilled.
	* Makefile.in (loop-invariant.o): Add $(TARGET_H).


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@192566 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 17 insertions, 1 deletions

diff --git a/gcc/loop-invariant.c b/gcc/loop-invariant.c
index a420569fd43..854b41c2ed6 100644
--- a/gcc/loop-invariant.c
+++ b/gcc/loop-invariant.c
@@ -47,6 +47,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "cfgloop.h"
 #include "expr.h"
 #include "recog.h"
+#include "target.h"
 #include "function.h"
 #include "flags.h"
 #include "df.h"
@@ -784,7 +785,22 @@ check_dependency (basic_block bb, df_ref use, bitmap depends_on)
 
   defs = DF_REF_CHAIN (use);
   if (!defs)
-    return true;
+    {
+      unsigned int regno = DF_REF_REGNO (use);
+
+      /* If this is the use of an uninitialized argument register that is
+	 likely to be spilled, do not move it lest this might extend its
+	 lifetime and cause reload to die.  This can occur for a call to
+	 a function taking complex number arguments and moving the insns
+	 preparing the arguments without moving the call itself wouldn't
+	 gain much in practice.  */
+      if ((DF_REF_FLAGS (use) & DF_HARD_REG_LIVE)
+	  && FUNCTION_ARG_REGNO_P (regno)
+	  && targetm.class_likely_spilled_p (REGNO_REG_CLASS (regno)))
+	return false;
+
+      return true;
+    }
 
   if (defs->next)
     return false;