[C] Improve diagnostics for vector types

Given the following invalid arm_neon.h-based code:

  float x;
  int8x8_t y = x;

the error message we emit is pretty good:

  incompatible types when initializing type 'int8x8_t' using type 'float'

But convert the types to pointers:

  int8x8_t *ptr = &x;

and the message becomes:

  initialization of '__vector(8) signed char *' from incompatible pointer type 'float *'

Although it's reasonably obvious what '__vector(8) signed char *' means,
it isn't valid C or C++ syntax and is quite far from what the user wrote,
so using 'int8x8_t *' would be better.

This patch therefore prints the type name of vectors that have one.
It's still OK to print the __vector syntax as an "aka", although I have
a follow-on patch to tweak this slightly for types defined in system
header files.  The follow-on patch also addresses the ??? in
gcc.target/aarch64/diag_aka_1.c.

The C++ test already passed, but it seemed worth including for
consistency.

2019-10-01  Richard Sandiford  <richard.sandiford@arm.com>

gcc/c-family/
	* c-pretty-print.c (pp_c_specifier_qualifier_list): If a vector type
	has a type name, use it in preference to the __vector syntax.

gcc/testsuite/
	* gcc.dg/diag-aka-3.c: New test.
	* gcc.target/aarch64/diag_aka_1.c: New test.
	* g++.dg/diagnostic/aka4.C: New test.

From-SVN: r276394

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index d0973ddd03a170a84550a2a28f06467810be698d..eaea04b9635280fd3858a45db439c6c299753caf 100644 (file)
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,8 @@
+2019-10-01  Richard Sandiford  <richard.sandiford@arm.com>
+
+       * c-pretty-print.c (pp_c_specifier_qualifier_list): If a vector type
+       has a type name, use it in preference to the __vector syntax.
+
 2019-09-30  Richard Sandiford  <richard.sandiford@arm.com>
 
        * c-pretty-print.c (pp_c_parameter_type_list): Avoid printing

diff --git a/gcc/c-family/c-pretty-print.c b/gcc/c-family/c-pretty-print.c
index e5cad67946ec828e1f4e6968803d09a61faac268..1b06cc20f680c65c1034090e9ac3041f7a902cc5 100644 (file)
--- a/gcc/c-family/c-pretty-print.c
+++ b/gcc/c-family/c-pretty-print.c
@@ -470,6 +470,16 @@ pp_c_specifier_qualifier_list (c_pretty_printer *pp, tree t)
                             ? "_Complex" : "__complex__"));
       else if (code == VECTOR_TYPE)
        {
+         /* The syntax we print for vector types isn't real C or C++ syntax,
+            so it's better to print the type name if we have one.  */
+         tree name = TYPE_NAME (t);
+         if (!(pp->flags & pp_c_flag_gnu_v3)
+             && name
+             && TREE_CODE (name) == TYPE_DECL)
+           {
+             pp->id_expression (name);
+             break;
+           }
          pp_c_ws_string (pp, "__vector");
          pp_c_left_paren (pp);
          pp_wide_integer (pp, TYPE_VECTOR_SUBPARTS (t));

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2bf37cbbebdb48281517b853186fb7bb42b88457..af7f6a25a029715cc4f2aabb1b573b312952df9a 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2019-10-01  Richard Sandiford  <richard.sandiford@arm.com>
+
+       * gcc.dg/diag-aka-3.c: New test.
+       * gcc.target/aarch64/diag_aka_1.c: New test.
+       * g++.dg/diagnostic/aka4.C: New test.
+
 2019-10-01  Richard Sandiford  <richard.sandiford@arm.com>
 
        * gcc.target/aarch64/torture/simd-abi-10.c: New test.

diff --git a/gcc/testsuite/g++.dg/diagnostic/aka4.C b/gcc/testsuite/g++.dg/diagnostic/aka4.C
new file mode 100644 (file)
index 0000000..da8c579
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/aka4.C
@@ -0,0 +1,9 @@
+typedef unsigned int myvec __attribute__((vector_size (16)));
+
+void f (float x)
+{
+  myvec y = x; // { dg-error {cannot convert 'float' to 'myvec' {aka '__vector\([48]\) unsigned int'} in initialization} }
+  myvec *ptr = &x; // { dg-error {cannot convert 'float\*' to 'myvec\*' {aka '__vector\([48]\) unsigned int\*'} in initialization} }
+  const myvec *const_ptr = &x; // { dg-error {cannot convert 'float\*' to 'const myvec\*' {aka 'const __vector\([48]\) unsigned int\*'} in initialization} }
+  volatile myvec *volatile_ptr = &x; // { dg-error {cannot convert 'float\*' to 'volatile myvec\*' {aka 'volatile __vector\([48]\) unsigned int\*'} in initialization} }
+}

diff --git a/gcc/testsuite/gcc.dg/diag-aka-3.c b/gcc/testsuite/gcc.dg/diag-aka-3.c
new file mode 100644 (file)
index 0000000..a3778ed
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/diag-aka-3.c
@@ -0,0 +1,9 @@
+typedef unsigned int myvec __attribute__((vector_size (16)));
+
+void f (float x)
+{
+  myvec y = x; /* { dg-error {incompatible types when initializing type 'myvec' {aka '__vector\([48]\) unsigned int'} using type 'float'} } */
+  myvec *ptr = &x; /* { dg-error {initialization of 'myvec \*' {aka '__vector\([48]\) unsigned int \*'} from incompatible pointer type 'float \*'} } */
+  const myvec *const_ptr = &x; /* { dg-error {initialization of 'const myvec \*' {aka 'const __vector\([48]\) unsigned int \*'} from incompatible pointer type 'float \*'} } */
+  volatile myvec *volatile_ptr = &x; /* { dg-error {initialization of 'volatile myvec \*' {aka 'volatile __vector\([48]\) unsigned int \*'} from incompatible pointer type 'float \*'} } */
+}

diff --git a/gcc/testsuite/gcc.target/aarch64/diag_aka_1.c b/gcc/testsuite/gcc.target/aarch64/diag_aka_1.c
new file mode 100644 (file)
index 0000000..59e24f4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/diag_aka_1.c
@@ -0,0 +1,14 @@
+#include <arm_neon.h>
+
+typedef int16x4_t myvec;
+
+void f (float x)
+{
+  __Int8x8_t y1 = x; /* { dg-error {incompatible types when initializing type '__Int8x8_t' using type 'float'} } */
+  __Int8x8_t *ptr1 = &x; /* { dg-error {initialization of '__Int8x8_t \*' from incompatible pointer type 'float \*'} } */
+  int8x8_t y2 = x; /* { dg-error {incompatible types when initializing type 'int8x8_t' using type 'float'} } */
+  int8x8_t *ptr2 = &x; /* { dg-error {initialization of 'int8x8_t \*' from incompatible pointer type 'float \*'} } */
+  /* ??? For these it would be better to print an aka for 'int16x4_t'.  */
+  myvec y3 = x; /* { dg-error {incompatible types when initializing type 'myvec' using type 'float'} } */
+  myvec *ptr3 = &x; /* { dg-error {initialization of 'myvec \*' from incompatible pointer type 'float \*'} } */
+}