From: Ed Schonberg <schonberg@adacore.com>
Date: Tue, 31 Jul 2018 09:55:48 +0000 (+0000)
Subject: [Ada] Spurious warning on iteration over range of 64-bit modular type
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c4a2e585d3b4e829f48fcb3c2a825584890b4fda;p=gcc.git

[Ada] Spurious warning on iteration over range of 64-bit modular type

This patch suppresses a spurious warning on the use of a 64-bit modular type
in a quantified expression, where the range of iteration will include a bound
that appears larger than the run-time representation of Universal_Integer'last.

2018-07-31  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* sem_eval.adb (Check_Non_Static_Context): Do not warn on an
	integer literal greater than the upper bound of
	Universal_Integer'Last when expansion is disabled, to avoid a
	spurious warning over ranges involving 64-bit modular types.

gcc/testsuite/

	* gnat.dg/iter3.adb: New testcase.

From-SVN: r263095
---

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index f91727b7f13..8b286057c1c 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,10 @@
+2018-07-31  Ed Schonberg  <schonberg@adacore.com>
+
+	* sem_eval.adb (Check_Non_Static_Context): Do not warn on an
+	integer literal greater than the upper bound of
+	Universal_Integer'Last when expansion is disabled, to avoid a
+	spurious warning over ranges involving 64-bit modular types.
+
 2018-07-31  Arnaud Charlet  <charlet@adacore.com>
 
 	* einfo.adb (Write_Entity_Flags): Also print
diff --git a/gcc/ada/sem_eval.adb b/gcc/ada/sem_eval.adb
index c14347b0e7d..4560a512fb8 100644
--- a/gcc/ada/sem_eval.adb
+++ b/gcc/ada/sem_eval.adb
@@ -547,9 +547,15 @@ package body Sem_Eval is
       --  called in contexts like the expression of a number declaration where
       --  we certainly want to allow out of range values.
 
+      --  We inhibit the warning when expansion is disabled, because the
+      --  preanalysis of a range of a 64-bit modular type may appear to
+      --  violate the constraint on non-static Universal_Integer. If there
+      --  is a true overflow it will be diagnosed during full analysis.
+
       if Etype (N) = Universal_Integer
         and then Nkind (N) = N_Integer_Literal
         and then Nkind (Parent (N)) in N_Subexpr
+        and then Expander_Active
         and then
           (Intval (N) < Expr_Value (Type_Low_Bound (Universal_Integer))
              or else
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index eb6474211c0..fd3079cf907 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2018-07-31  Ed Schonberg  <schonberg@adacore.com>
+
+	* gnat.dg/iter3.adb: New testcase.
+
 2018-07-31  Andre Vieira  <andre.simoesdiasvieira@arm.com>
 
 	Revert 'AsyncI/O patch committed'
diff --git a/gcc/testsuite/gnat.dg/iter3.adb b/gcc/testsuite/gnat.dg/iter3.adb
new file mode 100644
index 00000000000..28c90a145d0
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/iter3.adb
@@ -0,0 +1,15 @@
+--  { dg-do compile }
+--  { dg-options "-gnata" }
+
+procedure Iter3 is
+   type Mod64 is mod 2 ** 64;
+
+   function F (X : Mod64) return Boolean is (X /= Mod64'Last);
+begin
+   pragma Assert (for all X in Mod64 => F(X));
+   pragma Assert (for all X in Mod64'Range => F(X));
+
+  for X in Mod64'Range loop
+      null;
+  end loop;
+end;