c++: Fix thinko in enum_min_precision [PR61414]

When backporting the PR61414 fix to 8.4, I've noticed that the caching
of prec is actually broken, as it would fail to actually store the computed
precision into the hash_map's value and so next time we'd think the enum needs
0 bits.

2020-02-14  Jakub Jelinek  <jakub@redhat.com>

	PR c++/61414
	* class.c (enum_min_precision): Change prec type from int to int &.

	* g++.dg/cpp0x/enum39.C: New test.

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 11acab7008ee98f9cd81d4bc508a6a3f58e62f7e..a3d904e7bbb0d4c9f5a43aa82822ea18c248a953 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,8 @@
 2020-02-14  Jakub Jelinek  <jakub@redhat.com>
 
+       PR c++/61414
+       * class.c (enum_min_precision): Change prec type from int to int &.
+
        PR libstdc++/92906
        * cp-tree.h (enum cp_tree_index): Add CPTI_FALLBACK_DFLOAT32_TYPE,
        CPTI_FALLBACK_DFLOAT64_TYPE and CPTI_FALLBACK_DFLOAT128_TYPE.

diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index f9e46ca708f89ac35706934c63c6a1472f984a2d..a1fd1aa91ccbf1d1da81be5c9fff45abd47f3f29 100644 (file)
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -3289,7 +3289,7 @@ enum_min_precision (tree type)
     enum_to_min_precision = hash_map<tree, int>::create_ggc (37);
 
   bool existed;
-  int prec = enum_to_min_precision->get_or_insert (type, &existed);
+  int &prec = enum_to_min_precision->get_or_insert (type, &existed);
   if (existed)
     return prec;
 

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a69fa2c2947370bf280727b98d78704c33612155..3059e238ff31c8c4275e4e67b5909618f79cb0d8 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-02-14  Jakub Jelinek  <jakub@redhat.com>
+
+       PR c++/61414
+       * g++.dg/cpp0x/enum39.C: New test.
+
 2020-02-14  Martin Jambor  <mjambor@suse.cz>
 
        PR tree-optimization/93516

diff --git a/gcc/testsuite/g++.dg/cpp0x/enum39.C b/gcc/testsuite/g++.dg/cpp0x/enum39.C
new file mode 100644 (file)
index 0000000..676cf84
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/enum39.C
@@ -0,0 +1,15 @@
+// PR c++/61414
+// { dg-do compile { target c++11 } }
+
+enum class E { E0 = -4, E1 = 3 };
+enum F : unsigned { F0 = 0, F1 = 15 };
+
+struct S
+{
+  E a : 2;     // { dg-warning "'S::a' is too small to hold all values of 'enum class E'" }
+  E b : 2;     // { dg-warning "'S::b' is too small to hold all values of 'enum class E'" }
+  E c : 3;     // { dg-bogus "'S::c' is too small to hold all values of 'enum class E'" }
+  F d : 3;     // { dg-warning "'S::d' is too small to hold all values of 'enum F'" }
+  F e : 3;     // { dg-warning "'S::e' is too small to hold all values of 'enum F'" }
+  F f : 4;     // { dg-bogus "'S::f' is too small to hold all values of 'enum F'" }
+};