backport: re PR rtl-optimization/63659 (wrong code at -O2 and -O3 on x86_64-linux...

	Backported from mainline
	2014-10-31  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/63659
	* ree.c (update_reg_equal_equiv_notes): New function.
	(combine_set_extension, transform_ifelse): Use it.

	* gcc.c-torture/execute/pr63659.c: New test.

From-SVN: r218166

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 87730ce16ba8afe7dfbb7e8aad9d6808535d87bb..47fefa01be8a175d8b0178cde177f19cb18998a5 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,12 @@
 2014-11-28  Jakub Jelinek  <jakub@redhat.com>
 
        Backported from mainline
+       2014-10-31  Jakub Jelinek  <jakub@redhat.com>
+
+       PR rtl-optimization/63659
+       * ree.c (update_reg_equal_equiv_notes): New function.
+       (combine_set_extension, transform_ifelse): Use it.
+
        2014-10-03  Jakub Jelinek  <jakub@redhat.com>
 
        PR libgomp/61200

diff --git a/gcc/ree.c b/gcc/ree.c
index ff96df8a016beb285207d6bc2d3543725b4ac0c7..c7e106f9626976ab5ff89682360f26eac73eb903 100644 (file)
--- a/gcc/ree.c
+++ b/gcc/ree.c
@@ -261,6 +261,50 @@ typedef struct ext_cand
 
 static int max_insn_uid;
 
+/* Update or remove REG_EQUAL or REG_EQUIV notes for INSN.  */
+
+static bool
+update_reg_equal_equiv_notes (rtx insn, enum machine_mode new_mode,
+                             enum machine_mode old_mode, enum rtx_code code)
+{
+  rtx *loc = &REG_NOTES (insn);
+  while (*loc)
+    {
+      enum reg_note kind = REG_NOTE_KIND (*loc);
+      if (kind == REG_EQUAL || kind == REG_EQUIV)
+       {
+         rtx orig_src = XEXP (*loc, 0);
+         /* Update equivalency constants.  Recall that RTL constants are
+            sign-extended.  */
+         if (GET_CODE (orig_src) == CONST_INT
+             && HOST_BITS_PER_WIDE_INT >= GET_MODE_BITSIZE (new_mode))
+           {
+             if (INTVAL (orig_src) >= 0 || code == SIGN_EXTEND)
+               /* Nothing needed.  */;
+             else
+               {
+                 /* Zero-extend the negative constant by masking out the
+                    bits outside the source mode.  */
+                 rtx new_const_int
+                   = gen_int_mode (INTVAL (orig_src)
+                                   & GET_MODE_MASK (old_mode),
+                                   new_mode);
+                 if (!validate_change (insn, &XEXP (*loc, 0),
+                                       new_const_int, true))
+                   return false;
+               }
+             loc = &XEXP (*loc, 1);
+           }
+         /* Drop all other notes, they assume a wrong mode.  */
+         else if (!validate_change (insn, loc, XEXP (*loc, 1), true))
+           return false;
+       }
+      else
+       loc = &XEXP (*loc, 1);
+    }
+  return true;
+}
+
 /* Given a insn (CURR_INSN), an extension candidate for removal (CAND)
    and a pointer to the SET rtx (ORIG_SET) that needs to be modified,
    this code modifies the SET rtx to a new SET rtx that extends the
@@ -282,6 +326,7 @@ static bool
 combine_set_extension (ext_cand *cand, rtx curr_insn, rtx *orig_set)
 {
   rtx orig_src = SET_SRC (*orig_set);
+  enum machine_mode orig_mode = GET_MODE (SET_DEST (*orig_set));
   rtx new_reg = gen_rtx_REG (cand->mode, REGNO (SET_DEST (*orig_set)));
   rtx new_set;
 
@@ -296,9 +341,8 @@ combine_set_extension (ext_cand *cand, rtx curr_insn, rtx *orig_set)
        {
          /* Zero-extend the negative constant by masking out the bits outside
             the source mode.  */
-         enum machine_mode src_mode = GET_MODE (SET_DEST (*orig_set));
          rtx new_const_int
-           = GEN_INT (INTVAL (orig_src) & GET_MODE_MASK (src_mode));
+           = GEN_INT (INTVAL (orig_src) & GET_MODE_MASK (orig_mode));
          new_set = gen_rtx_SET (VOIDmode, new_reg, new_const_int);
        }
     }
@@ -336,7 +380,9 @@ combine_set_extension (ext_cand *cand, rtx curr_insn, rtx *orig_set)
 
   /* This change is a part of a group of changes.  Hence,
      validate_change will not try to commit the change.  */
-  if (validate_change (curr_insn, orig_set, new_set, true))
+  if (validate_change (curr_insn, orig_set, new_set, true)
+      && update_reg_equal_equiv_notes (curr_insn, cand->mode, orig_mode,
+                                      cand->code))
     {
       if (dump_file)
         {
@@ -385,7 +431,9 @@ transform_ifelse (ext_cand *cand, rtx def_insn)
   ifexpr = gen_rtx_IF_THEN_ELSE (cand->mode, cond, map_srcreg, map_srcreg2);
   new_set = gen_rtx_SET (VOIDmode, map_dstreg, ifexpr);
 
-  if (validate_change (def_insn, &PATTERN (def_insn), new_set, true))
+  if (validate_change (def_insn, &PATTERN (def_insn), new_set, true)
+      && update_reg_equal_equiv_notes (def_insn, cand->mode, GET_MODE (dstreg),
+                                      cand->code))
     {
       if (dump_file)
         {

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7b57f1222c7c3173b4bfcf7360bf1be6c7a3df44..38d5c102bce69415bc74d7cb65e0320ebb8d9e58 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2014-11-28  Jakub Jelinek  <jakub@redhat.com>
 
        Backported from mainline
+       2014-10-31  Jakub Jelinek  <jakub@redhat.com>
+
+       PR rtl-optimization/63659
+       * gcc.c-torture/execute/pr63659.c: New test.
+
        2014-10-03  Jakub Jelinek  <jakub@redhat.com>
 
        PR libgomp/61200

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr63659.c b/gcc/testsuite/gcc.c-torture/execute/pr63659.c
new file mode 100644 (file)
index 0000000..780dc8a
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr63659.c
@@ -0,0 +1,29 @@
+/* PR rtl-optimization/63659 */
+
+int a, b, c, *d = &b, g, h, i;
+unsigned char e;
+char f;
+
+int
+main ()
+{
+  while (a)
+    {
+      for (a = 0; a; a++)
+       for (; c; c++)
+         ;
+      if (i)
+       break;
+    }
+
+  char j = c, k = -1, l;
+  l = g = j >> h;
+  f = l == 0 ? k : k % l;
+  e = 0 ? 0 : f;
+  *d = e;
+
+  if (b != 255)
+    __builtin_abort ();
+
+  return 0;
+}