[gcc r13-925] tree-optimization/105802 - another unswitching type issue

[gcc r13-925] tree-optimization/105802 - another unswitching type issue

[Richard Biener]

https://gcc.gnu.org/g:4a6b8d9aad9f68eec223cc126d9effbf45e37271

commit r13-925-g4a6b8d9aad9f68eec223cc126d9effbf45e37271
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Jun 1 15:42:06 2022 +0200

    tree-optimization/105802 - another unswitching type issue
    
    This also fixes the type of the irange used for unswitching of
    switch statements.
    
            PR tree-optimization/105802
            * tree-ssa-loop-unswitch.cc (find_unswitching_predicates_for_bb):
            Make sure to also compute the range in the type of the switch index.
    
            * g++.dg/opt/pr105802.C: New testcase.

Diff:
---
 gcc/testsuite/g++.dg/opt/pr105802.C | 23 +++++++++++++++++++++++
 gcc/tree-ssa-loop-unswitch.cc       | 17 +++++++----------
 2 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/gcc/testsuite/g++.dg/opt/pr105802.C b/gcc/testsuite/g++.dg/opt/pr105802.C
new file mode 100644
index 00000000000..2514245d00a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/pr105802.C
@@ -0,0 +1,23 @@
+// { dg-do compile }
+// { dg-options "-O3" }
+
+enum E { E0, E1 };
+
+void bar ();
+void baz ();
+
+int c;
+
+void
+foo (int i)
+{
+  E e = (E) i;
+  while (c)
+    switch (e)
+      {
+      case E0:
+        bar ();
+      case E1:
+        baz ();
+      }
+}
diff --git a/gcc/tree-ssa-loop-unswitch.cc b/gcc/tree-ssa-loop-unswitch.cc
index 2b6013e9d69..61c04ed9f2e 100644
--- a/gcc/tree-ssa-loop-unswitch.cc
+++ b/gcc/tree-ssa-loop-unswitch.cc
@@ -523,22 +523,19 @@ find_unswitching_predicates_for_bb (basic_block bb, class loop *loop,
 	  tree lab = gimple_switch_label (stmt, i);
 	  tree cmp;
 	  int_range<2> lab_range;
+	  tree low = fold_convert (idx_type, CASE_LOW (lab));
 	  if (CASE_HIGH (lab) != NULL_TREE)
 	    {
-	      tree cmp1 = fold_build2 (GE_EXPR, boolean_type_node, idx,
-				       fold_convert (idx_type,
-						     CASE_LOW (lab)));
-	      tree cmp2 = fold_build2 (LE_EXPR, boolean_type_node, idx,
-				       fold_convert (idx_type,
-						     CASE_HIGH (lab)));
+	      tree high = fold_convert (idx_type, CASE_HIGH (lab));
+	      tree cmp1 = fold_build2 (GE_EXPR, boolean_type_node, idx, low);
+	      tree cmp2 = fold_build2 (LE_EXPR, boolean_type_node, idx, high);
 	      cmp = fold_build2 (BIT_AND_EXPR, boolean_type_node, cmp1, cmp2);
-	      lab_range.set (CASE_LOW (lab), CASE_HIGH (lab));
+	      lab_range.set (low, high);
 	    }
 	  else
 	    {
-	      cmp = fold_build2 (EQ_EXPR, boolean_type_node, idx,
-				 fold_convert (idx_type, CASE_LOW (lab)));
-	      lab_range.set (CASE_LOW (lab));
+	      cmp = fold_build2 (EQ_EXPR, boolean_type_node, idx, low);
+	      lab_range.set (low);
 	    }
 
 	  /* Combine the expression with the existing one.  */