re PR rtl-optimization/70467 (Useless "and [esp],-1" emitted on AND with uint64_t variable)

	PR rtl-optimization/70467
	* cse.c (cse_insn): Handle no-op MEM moves after folding.

	* gcc.target/i386/pr70467-1.c: New test.

From-SVN: r235765

1 files changed, 27 insertions, 1 deletions

diff --git a/gcc/cse.c b/gcc/cse.c
index 2665d9a..7456e84 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -4575,6 +4575,7 @@ cse_insn (rtx_insn *insn)
   for (i = 0; i < n_sets; i++)
     {
       bool repeat = false;
+      bool mem_noop_insn = false;
       rtx src, dest;
       rtx src_folded;
       struct table_elt *elt = 0, *p;
@@ -5166,7 +5167,7 @@ cse_insn (rtx_insn *insn)
 	    }
 
 	  /* Avoid creation of overlapping memory moves.  */
-	  if (MEM_P (trial) && MEM_P (SET_DEST (sets[i].rtl)))
+	  if (MEM_P (trial) && MEM_P (dest) && !rtx_equal_p (trial, dest))
 	    {
 	      rtx src, dest;
 
@@ -5277,6 +5278,21 @@ cse_insn (rtx_insn *insn)
 	      break;
 	    }
 
+	  /* Similarly, lots of targets don't allow no-op
+	     (set (mem x) (mem x)) moves.  */
+	  else if (n_sets == 1
+		   && MEM_P (trial)
+		   && MEM_P (dest)
+		   && rtx_equal_p (trial, dest)
+		   && !side_effects_p (dest)
+		   && (cfun->can_delete_dead_exceptions
+		       || insn_nothrow_p (insn)))
+	    {
+	      SET_SRC (sets[i].rtl) = trial;
+	      mem_noop_insn = true;
+	      break;
+	    }
+
 	  /* Reject certain invalid forms of CONST that we create.  */
 	  else if (CONSTANT_P (trial)
 		   && GET_CODE (trial) == CONST
@@ -5495,6 +5511,16 @@ cse_insn (rtx_insn *insn)
 	  sets[i].rtl = 0;
 	}
 
+      /* Similarly for no-op MEM moves.  */
+      else if (mem_noop_insn)
+	{
+	  if (cfun->can_throw_non_call_exceptions && can_throw_internal (insn))
+	    cse_cfg_altered = true;
+	  delete_insn_and_edges (insn);
+	  /* No more processing for this set.  */
+	  sets[i].rtl = 0;
+	}
+
       /* If this SET is now setting PC to a label, we know it used to
 	 be a conditional or computed branch.  */
       else if (dest == pc_rtx && GET_CODE (src) == LABEL_REF