PR c++/92745 - bogus error when initializing array of vectors.

In r268428 I changed reshape_init_r in such a way that when it sees
a nested { } in a CONSTRUCTOR with missing braces, it just returns
the initializer:
+     else if (COMPOUND_LITERAL_P (stripped_init)
...
+         ++d->cur;
+         gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (stripped_init));
+         return init;

But as this test shows, that's incorrect: if TYPE is an array, we need
to proceed to reshape_init_array_1 which will iterate over the array
initializers:
 6006   /* Loop until there are no more initializers.  */
 6007   for (index = 0;
 6008        d->cur != d->end && (!sized_array_p || index <= max_index_cst);
 6009        ++index)
 6010     {
and update d.cur accordingly.  In other words, when reshape_init gets

{{col[0][0], col[1][0], col[2][0], col[3][0]},
 {col[0][1], col[1][1], col[2][1], col[3][1]},
 {col[0][2], col[1][2], col[2][2], col[3][2]},
 {col[0][3], col[1][3], col[2][3], col[3][3]}}

we recurse on the first element:
  {col[0][0], col[1][0], col[2][0], col[3][0]}
and we can't just move d.cur to point to
  {col[0][1], col[1][1], col[2][1], col[3][1]}
and return; we need to iterate, so that d.cur ends up being properly
updated, and after all initializers have been seen, points to d.end.
Currently we skip the loop, wherefore we hit this:

 6502   /* Make sure all the element of the constructor were used. Otherwise,
 6503      issue an error about exceeding initializers.  */
 6504   if (d.cur != d.end)
 6505     {
 6506       if (complain & tf_error)
 6507         error ("too many initializers for %qT", type);
 6508       return error_mark_node;
 6509     }

gcc/cp/ChangeLog
2019-12-19  Marek Polacek  <polacek@redhat.com>

	PR c++/92745 - bogus error when initializing array of vectors.
	* decl.c (reshape_init_r): For a nested compound literal, do
	call reshape_init_{class,array,vector}.

gcc/testsuite/ChangeLog
2019-12-19  Marek Polacek  <polacek@redhat.com>
	    Jakub Jelinek  <jakub@redhat.com>

	PR c++/92745 - bogus error when initializing array of vectors.
	* g++.dg/cpp0x/initlist118.C: New test.
	* g++.dg/cpp0x/initlist118.C: Add -Wno-psabi -w to dg-options.

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 2b83f4da57834b02797233e880a440a735c412ad..8032f1c13fee64d012e71cf1cb6b8ce7c72a4ec8 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-02-26  Marek Polacek  <polacek@redhat.com>
+
+       PR c++/92745 - bogus error when initializing array of vectors.
+       * decl.c (reshape_init_r): For a nested compound literal, do
+       call reshape_init_{class,array,vector}.
+
 2020-02-26  Jason Merrill  <jason@redhat.com>
 
        PR c++/90951

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index b106d8f44adf0c0b7e3dbc61accf6b1ddab03b09..39d55589ef329209e1876170fb888ea8862e7b98 100644 (file)
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -6224,14 +6224,13 @@ reshape_init_r (tree type, reshape_iter *d, bool first_initializer_p,
               by the front end.  Here we have e.g. {.__pfn=0B, .__delta=0},
               which is missing outermost braces.  We should warn below, and
               one of the routines below will wrap it in additional { }.  */;
-         /* For a nested compound literal, there is no need to reshape since
-            we called reshape_init in finish_compound_literal, before calling
-            digest_init.  */
-         else if (COMPOUND_LITERAL_P (stripped_init)
-                  /* Similarly, a CONSTRUCTOR of the target's type is a
-                     previously digested initializer.  */
-                  || same_type_ignoring_top_level_qualifiers_p (type,
-                                                                init_type))
+         /* For a nested compound literal, proceed to specialized routines,
+            to handle initialization of arrays and similar.  */
+         else if (COMPOUND_LITERAL_P (stripped_init))
+           gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (stripped_init));
+         /* A CONSTRUCTOR of the target's type is a previously
+            digested initializer.  */
+         else if (same_type_ignoring_top_level_qualifiers_p (type, init_type))
            {
              ++d->cur;
              gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (stripped_init));

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 31c7e4dc7a85ac442ee11977a4bd51efd0981249..845976a9a3dfd4b65b0a326c133529d4f3e89ce4 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2020-02-26  Marek Polacek  <polacek@redhat.com>
+           Jakub Jelinek  <jakub@redhat.com>
+
+       PR c++/92745 - bogus error when initializing array of vectors.
+       * g++.dg/cpp0x/initlist118.C: New test.
+       * g++.dg/cpp0x/initlist118.C: Add -Wno-psabi -w to dg-options.
+
 2020-02-26  Jiufu Guo  <guojiufu@linux.ibm.com>
 
        PR target/93047

diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist118.C b/gcc/testsuite/g++.dg/cpp0x/initlist118.C
new file mode 100644 (file)
index 0000000..a226766
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/initlist118.C
@@ -0,0 +1,26 @@
+// PR c++/92745 - bogus error when initializing array of vectors.
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wno-psabi -w" }
+
+template <typename a, int b> struct c {
+  typedef a d[b];
+};
+
+template <typename a, int b> struct array {
+  typename c<a, b>::d e;
+  a operator[](long);
+};
+
+template<class T>
+using vec4_t __attribute__((vector_size(4*sizeof(T)))) = float;
+
+array<vec4_t<float>, 4>
+transpose(array<vec4_t<float>, 4> col)
+{
+  array<vec4_t<float>, 4>
+    ret{vec4_t<float>{col[0][0], col[1][0], col[2][0], col[3][0]},
+        vec4_t<float>{col[0][1], col[1][1], col[2][1], col[3][1]},
+        vec4_t<float>{col[0][2], col[1][2], col[2][2], col[3][2]},
+        vec4_t<float>{col[0][3], col[1][3], col[2][3], col[3][3]}};
+  return ret;
+}