[gcc(refs/vendors/redhat/heads/gcc-8-branch)] PR c++/92745 - bogus error when initializing array of vectors.

[Jakub Jelinek <jakub@gcc.gnu.org>]

https://gcc.gnu.org/g:98b9702e3a5e8449a1c4f058fe00e5466f5d47d8

commit 98b9702e3a5e8449a1c4f058fe00e5466f5d47d8
Author: Marek Polacek <polacek@redhat.com>
Date:   Fri Dec 20 23:30:04 2019 +0000

    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
    2020-02-25  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
    2020-02-25  Marek Polacek  <polacek@redhat.com>
                Jakub Jelinek  <jakub@redhat.com>
    
            PR c++/92745
            * g++.dg/cpp0x/initlist118.C: New test.
            * g++.dg/cpp0x/initlist118.C: Add -Wno-psabi -w to dg-options.

Diff:
---
 gcc/cp/ChangeLog                         |  6 ++++++
 gcc/cp/decl.c                            | 15 +++++++--------
 gcc/testsuite/ChangeLog                  |  7 +++++++
 gcc/testsuite/g++.dg/cpp0x/initlist118.C | 26 ++++++++++++++++++++++++++
 4 files changed, 46 insertions(+), 8 deletions(-)

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index a1fee505da6..b73cc568b63 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-02-25  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}.
+
 2020-02-25  Jason Merrill  <jason@redhat.com>
 
 	PR c++/89917 - ICE with lambda in variadic mem-init.
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index c55cdbed170..6dc23ec3273 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -6162,14 +6162,13 @@ 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 (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 (init))
+	    gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (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 (init));
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index beb1092cd87..c893053097f 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2020-02-25  Marek Polacek  <polacek@redhat.com>
+	    Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/92745
+	* g++.dg/cpp0x/initlist118.C: New test.
+	* g++.dg/cpp0x/initlist118.C: Add -Wno-psabi -w to dg-options.
+
 2020-02-25  Jakub Jelinek  <jakub@redhat.com>
 
 	PR rtl-optimization/93908
diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist118.C b/gcc/testsuite/g++.dg/cpp0x/initlist118.C
new file mode 100644
index 00000000000..a2267661532
--- /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;
+}