[COMMITTED 2/2] Always do PHI analysis before loop analysis.

[Andrew MacLeod <amacleod@redhat.com>]

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The original invocation of phi_analysis was only invoked if there was no 
loop information available.  I have found situations where phi analysis 
enhances existing loop information, and as such this patch moves the phi 
analysis block to before loop analysis is invoked (in case a query is 
made from within that area), and does it unconditionally.  There is 
minimal impact on compilation time.

Bootstrapped on x86_64-pc-linux-gnu with no regressions.  Pushed.

Andrew

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From 5d5f90ec3b4a939cae5ce4f33b76849f6b08e3a9 Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacleod@redhat.com>
Date: Wed, 13 Sep 2023 10:09:16 -0400
Subject: [PATCH 2/3] Always do PHI analysis and before loop analysis.

PHI analysis wasn't being done if loop analysis found a value.  Always
do the PHI analysis, and run it for an iniital value before invoking
loop analysis.

	* gimple-range-fold.cc (fold_using_range::range_of_phi): Always
	run phi analysis, and do it before loop analysis.
---
 gcc/gimple-range-fold.cc | 53 ++++++++++++++++++++--------------------
 1 file changed, 26 insertions(+), 27 deletions(-)

diff --git a/gcc/gimple-range-fold.cc b/gcc/gimple-range-fold.cc
index 03805d88d9b..d1945ccb554 100644
--- a/gcc/gimple-range-fold.cc
+++ b/gcc/gimple-range-fold.cc
@@ -939,7 +939,32 @@ fold_using_range::range_of_phi (vrange &r, gphi *phi, fur_source &src)
 	}
     }
 
-  bool loop_info_p = false;
+  // If PHI analysis is available, see if there is an iniital range.
+  if (phi_analysis_available_p ()
+      && irange::supports_p (TREE_TYPE (phi_def)))
+    {
+      phi_group *g = (phi_analysis())[phi_def];
+      if (g && !(g->range ().varying_p ()))
+	{
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fprintf (dump_file, "PHI GROUP query for ");
+	      print_generic_expr (dump_file, phi_def, TDF_SLIM);
+	      fprintf (dump_file, " found : ");
+	      g->range ().dump (dump_file);
+	      fprintf (dump_file, " and adjusted original range from :");
+	      r.dump (dump_file);
+	    }
+	  r.intersect (g->range ());
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fprintf (dump_file, " to :");
+	      r.dump (dump_file);
+	      fprintf (dump_file, "\n");
+	    }
+	}
+    }
+
   // If SCEV is available, query if this PHI has any known values.
   if (scev_initialized_p ()
       && !POINTER_TYPE_P (TREE_TYPE (phi_def)))
@@ -962,32 +987,6 @@ fold_using_range::range_of_phi (vrange &r, gphi *phi, fur_source &src)
 		  fprintf (dump_file, "\n");
 		}
 	      r.intersect (loop_range);
-	      loop_info_p = true;
-	    }
-	}
-    }
-
-  if (!loop_info_p && phi_analysis_available_p ()
-      && irange::supports_p (TREE_TYPE (phi_def)))
-    {
-      phi_group *g = (phi_analysis())[phi_def];
-      if (g && !(g->range ().varying_p ()))
-	{
-	  if (dump_file && (dump_flags & TDF_DETAILS))
-	    {
-	      fprintf (dump_file, "PHI GROUP query for ");
-	      print_generic_expr (dump_file, phi_def, TDF_SLIM);
-	      fprintf (dump_file, " found : ");
-	      g->range ().dump (dump_file);
-	      fprintf (dump_file, " and adjusted original range from :");
-	      r.dump (dump_file);
-	    }
-	  r.intersect (g->range ());
-	  if (dump_file && (dump_flags & TDF_DETAILS))
-	    {
-	      fprintf (dump_file, " to :");
-	      r.dump (dump_file);
-	      fprintf (dump_file, "\n");
 	    }
 	}
     }
-- 
2.41.0