From 663f4248bd8946b76b0a898b405afd7d40a307a9 Mon Sep 17 00:00:00 2001
From: jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Mon, 2 May 2016 16:46:10 +0000
Subject: [PATCH] 	PR rtl-optimization/70467 	* cse.c (cse_insn):
 Handle no-op MEM moves after folding.

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


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@235765 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/ChangeLog                             |  3 ++
 gcc/cse.c                                 | 28 +++++++++++++++-
 gcc/testsuite/ChangeLog                   |  5 +++
 gcc/testsuite/gcc.target/i386/pr70467-1.c | 55 +++++++++++++++++++++++++++++++
 4 files changed, 90 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr70467-1.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5bf2ffa7c35..a5339da2527 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,9 @@
 2016-05-02  Jakub Jelinek  <jakub@redhat.com>
 
 	PR rtl-optimization/70467
+	* cse.c (cse_insn): Handle no-op MEM moves after folding.
+
+	PR rtl-optimization/70467
 	* ipa-pure-const.c (check_call): Handle internal calls even in
 	ipa mode like in local mode.
 
diff --git a/gcc/cse.c b/gcc/cse.c
index 2665d9a2733..7456e84c329 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
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7d7dae4dcf9..328a9a5f056 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-05-02  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/70467
+	* gcc.target/i386/pr70467-1.c: New test.
+
 2016-05-02  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	* gcc.dg/spec-options.c: Run the test on all targets.
diff --git a/gcc/testsuite/gcc.target/i386/pr70467-1.c b/gcc/testsuite/gcc.target/i386/pr70467-1.c
new file mode 100644
index 00000000000..4e112c88d07
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr70467-1.c
@@ -0,0 +1,55 @@
+/* PR rtl-optimization/70467 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -mno-sse" } */
+
+void foo (unsigned long long *);
+
+void
+bar (void)
+{
+  unsigned long long a;
+  foo (&a);
+  a &= 0x7fffffffffffffffULL;
+  foo (&a);
+  a &= 0xffffffff7fffffffULL;
+  foo (&a);
+  a &= 0x7fffffff00000000ULL;
+  foo (&a);
+  a &= 0x000000007fffffffULL;
+  foo (&a);
+  a &= 0x00000000ffffffffULL;
+  foo (&a);
+  a &= 0xffffffff00000000ULL;
+  foo (&a);
+  a |= 0x7fffffffffffffffULL;
+  foo (&a);
+  a |= 0xffffffff7fffffffULL;
+  foo (&a);
+  a |= 0x7fffffff00000000ULL;
+  foo (&a);
+  a |= 0x000000007fffffffULL;
+  foo (&a);
+  a |= 0x00000000ffffffffULL;
+  foo (&a);
+  a |= 0xffffffff00000000ULL;
+  foo (&a);
+  a ^= 0x7fffffffffffffffULL;
+  foo (&a);
+  a ^= 0xffffffff7fffffffULL;
+  foo (&a);
+  a ^= 0x7fffffff00000000ULL;
+  foo (&a);
+  a ^= 0x000000007fffffffULL;
+  foo (&a);
+  a ^= 0x00000000ffffffffULL;
+  foo (&a);
+  a ^= 0xffffffff00000000ULL;
+  foo (&a);
+}
+
+/* { dg-final { scan-assembler-not "andl\[ \t\]*.-1," { target ia32 } } } */
+/* { dg-final { scan-assembler-not "andl\[ \t\]*.0," { target ia32 } } } */
+/* { dg-final { scan-assembler-not "orl\[ \t\]*.-1," { target ia32 } } } */
+/* { dg-final { scan-assembler-not "orl\[ \t\]*.0," { target ia32 } } } */
+/* { dg-final { scan-assembler-not "xorl\[ \t\]*.-1," { target ia32 } } } */
+/* { dg-final { scan-assembler-not "xorl\[ \t\]*.0," { target ia32 } } } */
-- 
2.11.4.GIT