[committed] aarch64: Fix build against libc++ in c++11 mode [PR113763]

[committed] aarch64: Fix build against libc++ in c++11 mode [PR113763]

[Jakub Jelinek]

Hi!

std::pair ctor used in tiles constexpr variable is only constexpr in C++14
and later, it works with libstdc++ because it is marked constexpr there even
in C++11 mode.

The following patch fixes it by using an unnamed local class instead of
std::pair, and additionally changes the first element from unsigned int to
unsigned char because 0xff has to fit into unsigned char on all hosts.

Bootstrapped/regtested on aarch64-linux, preapproved by Richard in the PR,
committed to trunk.

2024-02-06  Jakub Jelinek  <jakub@redhat.com>

	PR target/113763
	* config/aarch64/aarch64.cc (aarch64_output_sme_zero_za): Change tiles
	element from std::pair<unsigned int, char> to an unnamed struct.
	Adjust uses of tile range variable.

--- gcc/config/aarch64/aarch64.cc.jj	2024-02-06 08:43:14.899888072 +0100
+++ gcc/config/aarch64/aarch64.cc	2024-02-06 11:41:47.855049148 +0100
@@ -13130,7 +13130,7 @@ aarch64_output_sme_zero_za (rtx mask)
   if (mask_val == 0xff)
     return "zero\t{ za }";
 
-  static constexpr std::pair<unsigned int, char> tiles[] = {
+  static constexpr struct { unsigned char mask; char letter; } tiles[] = {
     { 0xff, 'b' },
     { 0x55, 'h' },
     { 0x11, 's' },
@@ -13144,14 +13144,14 @@ aarch64_output_sme_zero_za (rtx mask)
   const char *prefix = "{ ";
   for (auto &tile : tiles)
     {
-      auto tile_mask = tile.first;
+      unsigned int tile_mask = tile.mask;
       unsigned int tile_index = 0;
       while (tile_mask < 0x100)
 	{
 	  if ((mask_val & tile_mask) == tile_mask)
 	    {
 	      i += snprintf (buffer + i, sizeof (buffer) - i, "%sza%d.%c",
-			     prefix, tile_index, tile.second);
+			     prefix, tile_index, tile.letter);
 	      prefix = ", ";
 	      mask_val &= ~tile_mask;
 	    }

	Jakub