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

[Richard Biener <rguenther@suse.de>]

On December 5, 2020 11:59:22 AM GMT+01:00, Jakub Jelinek <jakub@redhat.com> wrote:
>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?

Ok. 

Richard. 

>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