[PATCH] phiopt, v2: Handle bool in two_value_replacement [PR796232]

[Jakub Jelinek <jakub@redhat.com>]

On Sat, Dec 05, 2020 at 11:22:24AM +0100, Richard Biener wrote:
> >two_value_replacement and didn't restrict it to !early_p.  Shall we
> >instead
> >do two_value_replacement only in late phiopt?
> 
> Yeah, I guess that would make sense.  I don't remember exactly but I saw
> regressions with early doing if conversion besides min/max/abs detection.

So that would be then following patch instead.
Ok if it passes bootstrap/regtest?

2020-12-05  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/96232
	* tree-ssa-phiopt.c (two_value_replacement): Optimize even boolean lhs
	cases as long as arg0 has wider precision and conditional_replacement
	doesn't handle that case.
	(tree_ssa_phiopt_worker): Don't call two_value_replacement during
	early phiopt.

	* gcc.dg/tree-ssa/pr96232-2.c: New test.

--- gcc/tree-ssa-phiopt.c.jj	2020-12-05 11:37:39.216203475 +0100
+++ gcc/tree-ssa-phiopt.c	2020-12-05 11:51:57.497472991 +0100
@@ -337,7 +337,7 @@ tree_ssa_phiopt_worker (bool do_store_el
 	    }
 
 	  /* Do the replacement of conditional if it can be done.  */
-	  if (two_value_replacement (bb, bb1, e2, phi, arg0, arg1))
+	  if (!early_p && two_value_replacement (bb, bb1, e2, phi, arg0, arg1))
 	    cfgchanged = true;
 	  else if (!early_p
 		   && conditional_replacement (bb, bb1, e1, e2, phi,
@@ -635,7 +635,6 @@ two_value_replacement (basic_block cond_
 
   if (TREE_CODE (lhs) != SSA_NAME
       || !INTEGRAL_TYPE_P (TREE_TYPE (lhs))
-      || TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
       || TREE_CODE (rhs) != INTEGER_CST)
     return false;
 
@@ -648,9 +647,25 @@ two_value_replacement (basic_block cond_
       return false;
     }
 
+  /* Defer boolean x ? 0 : {1,-1} or x ? {1,-1} : 0 to
+     conditional_replacement.  */
+  if (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
+      && (integer_zerop (arg0)
+	  || integer_zerop (arg1)
+	  || TREE_CODE (TREE_TYPE (arg0)) == BOOLEAN_TYPE
+	  || (TYPE_PRECISION (TREE_TYPE (arg0))
+	      <= TYPE_PRECISION (TREE_TYPE (lhs)))))
+    return false;
+
   wide_int min, max;
-  if (get_range_info (lhs, &min, &max) != VR_RANGE
-      || min + 1 != max
+  if (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE)
+    {
+      min = wi::to_wide (boolean_false_node);
+      max = wi::to_wide (boolean_true_node);
+    }
+  else if (get_range_info (lhs, &min, &max) != VR_RANGE)
+    return false;
+  if (min + 1 != max
       || (wi::to_wide (rhs) != min
 	  && wi::to_wide (rhs) != max))
     return false;
--- gcc/testsuite/gcc.dg/tree-ssa/pr96232-2.c.jj	2020-12-05 11:51:01.891103252 +0100
+++ gcc/testsuite/gcc.dg/tree-ssa/pr96232-2.c	2020-12-05 11:51:01.891103252 +0100
@@ -0,0 +1,18 @@
+/* PR tree-optimization/96232 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump " 38 - " "optimized" } } */
+/* { dg-final { scan-tree-dump " \\+ 97;" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "PHI <" "optimized" } } */
+
+int
+foo (_Bool x)
+{
+  return x ? 37 : 38;
+}
+
+int
+bar (_Bool x)
+{
+  return x ? 98 : 97;
+}


	Jakub