[PATCH] Make VRP union faster

[Richard Biener]

The following addresses value_range::union_ranges which ends up
doing quite some redundant work for the PR91257 testcase via
PHI argument processing.  compare_values isn't really much
slower once you may end up needing more than a single
operand_less_p - in fact for non-constant ranges it often ends
up dispatching there.

Bootstrap / regtest running on x86_64-unknown-linux-gnu.

Richard.

2019-07-30  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/91257
	* tree-vrp.c (union_ranges): Unify equality and less tests
	by using compare_values.  Re-order cheap tests first.

Index: gcc/tree-vrp.c
===================================================================
--- gcc/tree-vrp.c	(revision 273795)
+++ gcc/tree-vrp.c	(working copy)
@@ -5468,8 +5474,10 @@ union_ranges (enum value_range_kind *vr0
 	      enum value_range_kind vr1type,
 	      tree vr1min, tree vr1max)
 {
-  bool mineq = vrp_operand_equal_p (*vr0min, vr1min);
-  bool maxeq = vrp_operand_equal_p (*vr0max, vr1max);
+  int cmpmin = compare_values (*vr0min, vr1min);
+  int cmpmax = compare_values (*vr0max, vr1max);
+  bool mineq = cmpmin == 0;
+  bool maxeq = cmpmax == 0;
 
   /* [] is vr0, () is vr1 in the following classification comments.  */
   if (mineq && maxeq)
@@ -5569,8 +5577,8 @@ union_ranges (enum value_range_kind *vr0
       else
 	gcc_unreachable ();
     }
-  else if ((maxeq || operand_less_p (vr1max, *vr0max) == 1)
-	   && (mineq || operand_less_p (*vr0min, vr1min) == 1))
+  else if ((maxeq || cmpmax == 1)
+	   && (mineq || cmpmin == -1))
     {
       /* [ (  ) ] or [(  ) ] or [ (  )] */
       if (*vr0type == VR_RANGE
@@ -5603,8 +5611,8 @@ union_ranges (enum value_range_kind *vr0
       else
 	gcc_unreachable ();
     }
-  else if ((maxeq || operand_less_p (*vr0max, vr1max) == 1)
-	   && (mineq || operand_less_p (vr1min, *vr0min) == 1))
+  else if ((maxeq || cmpmax == -1)
+	   && (mineq || cmpmin == 1))
     {
       /* ( [  ] ) or ([  ] ) or ( [  ]) */
       if (*vr0type == VR_RANGE
@@ -5643,10 +5651,10 @@ union_ranges (enum value_range_kind *vr0
       else
 	gcc_unreachable ();
     }
-  else if ((operand_less_p (vr1min, *vr0max) == 1
-	    || operand_equal_p (vr1min, *vr0max, 0))
-	   && operand_less_p (*vr0min, vr1min) == 1
-	   && operand_less_p (*vr0max, vr1max) == 1)
+  else if (cmpmin == -1
+	   && cmpmax == -1
+	   && (operand_less_p (vr1min, *vr0max) == 1
+	       || operand_equal_p (vr1min, *vr0max, 0)))
     {
       /* [  (  ]  ) or [   ](   ) */
       if (*vr0type == VR_RANGE
@@ -5680,10 +5688,10 @@ union_ranges (enum value_range_kind *vr0
       else
 	gcc_unreachable ();
     }
-  else if ((operand_less_p (*vr0min, vr1max) == 1
-	    || operand_equal_p (*vr0min, vr1max, 0))
-	   && operand_less_p (vr1min, *vr0min) == 1
-	   && operand_less_p (vr1max, *vr0max) == 1)
+  else if (cmpmin == 1
+	   && cmpmax == 1
+	   && (operand_less_p (*vr0min, vr1max) == 1
+	       || operand_equal_p (*vr0min, vr1max, 0)))
     {
       /* (  [  )  ] or (   )[   ] */
       if (*vr0type == VR_RANGE