* sched-deps.c (sched_analyze_insn): Force volatile memory reads

        to be output before a branch.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@42358 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 13 insertions, 0 deletions

diff --git a/gcc/sched-deps.c b/gcc/sched-deps.c
index ecdf28212ba..d303e7a86df 100644
--- a/gcc/sched-deps.c
+++ b/gcc/sched-deps.c
@@ -1044,12 +1044,25 @@ sched_analyze_insn (deps, x, insn, loop_notes)
 
 	  CLEAR_REG_SET (&tmp);
 
+	  /* All memory writes and volatile reads must happen before the
+	     jump.  Non-volatile reads must happen before the jump iff
+	     the result is needed by the above register used mask.  */
+
 	  pending = deps->pending_write_insns;
 	  pending_mem = deps->pending_write_mems;
 	  while (pending)
 	    {
 	      add_dependence (insn, XEXP (pending, 0), REG_DEP_OUTPUT);
+	      pending = XEXP (pending, 1);
+	      pending_mem = XEXP (pending_mem, 1);
+	    }
 
+	  pending = deps->pending_read_insns;
+	  pending_mem = deps->pending_read_mems;
+	  while (pending)
+	    {
+	      if (MEM_VOLATILE_P (XEXP (pending_mem, 0)))
+		add_dependence (insn, XEXP (pending, 0), REG_DEP_OUTPUT);
 	      pending = XEXP (pending, 1);
 	      pending_mem = XEXP (pending_mem, 1);
 	    }