[committed] c++: Fix thinko in enum_min_precision [PR61414]
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Message ID 20200214164626.GQ17695@tucnak
State New
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  • [committed] c++: Fix thinko in enum_min_precision [PR61414]
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Commit Message

Jakub Jelinek Feb. 14, 2020, 4:46 p.m. UTC
Hi!

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.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux and
committed to trunk, 9.3 and 8.4.

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.


	Jakub

Patch
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--- gcc/cp/class.c.jj	2020-02-12 11:44:18.423371637 +0100
+++ gcc/cp/class.c	2020-02-14 14:33:41.842057349 +0100
@@ -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;
 
--- gcc/testsuite/g++.dg/cpp0x/enum39.C.jj	2020-02-14 14:30:26.489972394 +0100
+++ gcc/testsuite/g++.dg/cpp0x/enum39.C	2020-02-14 14:30:22.530031482 +0100
@@ -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'" }
+};