Don't save function_used_regs if it contains all call_used_regs

2014-06-20  Tom de Vries  <tom@codesourcery.com>

	* final.c (collect_fn_hard_reg_usage): Don't save function_used_regs if
	it contains all call_used_regs.

From-SVN: r211840

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e83b0ce18f358a5e1d4a4df423cc98a35d8f89bd..108bc5f5b8a62147b755e1938568524afd29f7fa 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2014-06-20  Tom de Vries  <tom@codesourcery.com>
+
+       * final.c (collect_fn_hard_reg_usage): Don't save function_used_regs if
+       it contains all call_used_regs.
+
 2014-06-20  Tom de Vries  <tom@codesourcery.com>
 
        * final.c (collect_fn_hard_reg_usage): Add and use variable

diff --git a/gcc/final.c b/gcc/final.c
index e39930d4207f2bce68e76b1aa1ec90daf0074d31..e67e84b8a2e8c255cbfb79cb1d7310a37835d58e 100644 (file)
--- a/gcc/final.c
+++ b/gcc/final.c
@@ -4795,6 +4795,11 @@ collect_fn_hard_reg_usage (void)
     SET_HARD_REG_BIT (function_used_regs, i);
 #endif
 
+  /* The information we have gathered is only interesting if it exposes a
+     register from the call_used_regs that is not used in this function.  */
+  if (hard_reg_set_subset_p (call_used_reg_set, function_used_regs))
+    return;
+
   node = cgraph_rtl_info (current_function_decl);
   gcc_assert (node != NULL);