ira: Fix unnecessary register spill

The variables first_moveable_pseudo and last_moveable_pseudo aren't
reset after compiling a function, which means they leak into the first
scheduler pass of the following function. In some cases, this can cause
an extra spill during register allocation of the second function.

gcc/ChangeLog:

	* ira.c (move_unallocated_pseudos): Zero first_moveable_pseudo and
	last_moveable_pseudo before returning.

gcc/testsuite/ChangeLog:

	* gcc.target/aarch64/nospill.c: New test.

1 files changed, 2 insertions, 0 deletions

diff --git a/gcc/ira.c b/gcc/ira.c
index a655ae1..b748a6d 100644
--- a/gcc/ira.c
+++ b/gcc/ira.c
@@ -5126,6 +5126,8 @@ move_unallocated_pseudos (void)
 		   INSN_UID (newinsn), i);
 	SET_REG_N_REFS (i, 0);
       }
+
+  first_moveable_pseudo = last_moveable_pseudo = 0;
 }
 
 /* If the backend knows where to allocate pseudos for hard