[gcc r12-6559] Allow more precision when querying from fold_const.

[gcc r12-6559] Allow more precision when querying from fold_const.

[Andrew Macleod]

https://gcc.gnu.org/g:49d5fb4feee831868d80fff4d024c271911c92ca

commit r12-6559-g49d5fb4feee831868d80fff4d024c271911c92ca
Author: Andrew MacLeod <amacleod@redhat.com>
Date:   Wed Jan 12 13:31:08 2022 -0500

    Allow more precision when querying from fold_const.
    
    fold_const::expr_not_equal_to queries for a current range, but still uses
    the old value_range class.  This is causing it to miss opportunities when
    ranger can provide something better.
    
            PR tree-optimization/83072
            PR tree-optimization/83073
            PR tree-optimization/97909
            gcc/
            * fold-const.c (expr_not_equal_to): Use a multi-range class.
    
            gcc/testsuite/
            * gcc.dg/pr83072-2.c: New.
            * gcc.dg/pr83073.c: New.

Diff:
---
 gcc/fold-const.c                 |  2 +-
 gcc/testsuite/gcc.dg/pr83072-2.c | 18 ++++++++++++++++++
 gcc/testsuite/gcc.dg/pr83073.c   | 10 ++++++++++
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 397fa9a03a1..cd540e1f2b3 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -10734,7 +10734,7 @@ tree_expr_nonzero_p (tree t)
 bool
 expr_not_equal_to (tree t, const wide_int &w)
 {
-  value_range vr;
+  int_range_max vr;
   switch (TREE_CODE (t))
     {
     case INTEGER_CST:
diff --git a/gcc/testsuite/gcc.dg/pr83072-2.c b/gcc/testsuite/gcc.dg/pr83072-2.c
new file mode 100644
index 00000000000..f495f2582c4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr83072-2.c
@@ -0,0 +1,18 @@
+/* { dg-do compile} */
+/* { dg-options "-O2 -fdump-tree-evrp-details" } */
+
+int f1(int a, int b, int c){
+  if(c==0)__builtin_unreachable();
+  a *= c;
+  b *= c;
+  return a == b;
+}
+
+int f2(int a, int b, int c){
+  c |= 1;
+  a *= c;
+  b *= c;
+  return a == b;
+}
+
+/* { dg-final { scan-tree-dump-times "gimple_simplified to" 2 "evrp" } }  */
diff --git a/gcc/testsuite/gcc.dg/pr83073.c b/gcc/testsuite/gcc.dg/pr83073.c
new file mode 100644
index 00000000000..1168ae822a4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr83073.c
@@ -0,0 +1,10 @@
+/* { dg-do compile} */
+/* { dg-options "-O2 -fdump-tree-evrp-details -fno-tree-fre -fno-tree-ccp -fno-tree-forwprop" } */
+
+int f(int x)
+{
+    x = x|1;
+    return x & 1;
+}
+
+/* { dg-final { scan-tree-dump "gimple_simplified to.* = 1" "evrp" } }  */