re PR rtl-optimization/68376 (wrong code at -O1 and above on x86_64-linux-gnu)

	PR rtl-optimization/68376
	* ifcvt.c (noce_try_abs): Disable one_cmpl optimization if
	encountering x <= 0 ? ~x : x or x > 0 ? ~x : x.

	* gcc.c-torture/execute/pr68376-1.c: New test.
	* gcc.c-torture/execute/pr68376-2.c: New test.

From-SVN: r230596

1 files changed, 41 insertions, 4 deletions

diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index 56e4ed42..eb5cae5 100644
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -2595,12 +2595,49 @@ noce_try_abs (struct noce_if_info *if_info)
 
   /* Work around funny ideas get_condition has wrt canonicalization.
      Note that these rtx constants are known to be CONST_INT, and
-     therefore imply integer comparisons.  */
+     therefore imply integer comparisons.
+     The one_cmpl case is more complicated, as we want to handle
+     only x < 0 ? ~x : x or x >= 0 ? ~x : x but not
+     x <= 0 ? ~x : x or x > 0 ? ~x : x, as the latter two
+     have different result for x == 0.  */
   if (c == constm1_rtx && GET_CODE (cond) == GT)
-    ;
+    {
+      if (one_cmpl && negate)
+	return FALSE;
+    }
   else if (c == const1_rtx && GET_CODE (cond) == LT)
-    ;
-  else if (c != CONST0_RTX (GET_MODE (b)))
+    {
+      if (one_cmpl && !negate)
+	return FALSE;
+    }
+  else if (c == CONST0_RTX (GET_MODE (b)))
+    {
+      if (one_cmpl)
+	switch (GET_CODE (cond))
+	  {
+	  case GT:
+	    if (!negate)
+	      return FALSE;
+	    break;
+	  case GE:
+	    /* >= 0 is the same case as above > -1.  */
+	    if (negate)
+	      return FALSE;
+	    break;
+	  case LT:
+	    if (negate)
+	      return FALSE;
+	    break;
+	  case LE:
+	    /* <= 0 is the same case as above < 1.  */
+	    if (!negate)
+	      return FALSE;
+	    break;
+	  default:
+	    return FALSE;
+	  }
+    }
+  else
     return FALSE;
 
   /* Determine what sort of operation this is.  */