[Patch 3/2 ifcvt costs] Don't expand a conditional move between identical sources

gcc/

	* optabs.c (emit_condiitonal_move): Short circuit for identical
	sources.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@238595 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 11 insertions, 0 deletions

diff --git a/gcc/optabs.c b/gcc/optabs.c
index 51e10e21769..87b4f978420 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -4214,6 +4214,17 @@ emit_conditional_move (rtx target, enum rtx_code code, rtx op0, rtx op1,
   enum insn_code icode;
   enum rtx_code reversed;
 
+  /* If the two source operands are identical, that's just a move.  */
+
+  if (rtx_equal_p (op2, op3))
+    {
+      if (!target)
+	target = gen_reg_rtx (mode);
+
+      emit_move_insn (target, op3);
+      return target;
+    }
+
   /* If one operand is constant, make it the second one.  Only do this
      if the other operand is not constant as well.  */