[PATCH] nvptx: Fix up nvptx build against latest libstdc++ [PR100375]

[Jakub Jelinek via Gcc-patches]

Hi!

The r12-220-gd96db15967e78d7cecea3b1cf3169ceb924678ac change
deprecated some non-standard std::pair constructors and that apparently
broke nvptx.c build, where pseudo_node_t is std::pair<struct basic_block_def *, 
int>
and so nullptr (or NULL) needs to be used for the first argument of the
ctors instead of 0.

Tested in x86_64-linux -> nvptx-none cross with CC/CXX latest trunk gcc,
ok for trunk?

2021-05-02  Jakub Jelinek  <ja...@redhat.com>

        PR target/100375
        * config/nvptx/nvptx.c (nvptx_sese_pseudo): Use nullptr instead of 0
        as first argument of pseudo_node_t constructors.

--- gcc/config/nvptx/nvptx.c.jj 2021-02-10 23:08:50.487460416 +0100
+++ gcc/config/nvptx/nvptx.c    2021-05-02 10:39:45.803670287 +0200
@@ -3682,9 +3682,9 @@ nvptx_sese_pseudo (basic_block me, bb_se
   edge e;
   edge_iterator ei;
   int hi_back = depth;
-  pseudo_node_t node_back (0, depth);
+  pseudo_node_t node_back (nullptr, depth);
   int hi_child = depth;
-  pseudo_node_t node_child (0, depth);
+  pseudo_node_t node_child (nullptr, depth);
   basic_block child = NULL;
   unsigned num_children = 0;
   int usd = -dir * sese->dir;
@@ -3751,7 +3751,7 @@ nvptx_sese_pseudo (basic_block me, bb_se
       else
        { /* Fallen off graph, backlink to entry node.  */
          hi_back = 0;
-         node_back = pseudo_node_t (0, 0);
+         node_back = pseudo_node_t (nullptr, 0);
        }
     }
 
@@ -3772,7 +3772,7 @@ nvptx_sese_pseudo (basic_block me, bb_se
       else
        {
          /* back edge to entry node */
-         sese->push (pseudo_node_t (0, 0));
+         sese->push (pseudo_node_t (nullptr, 0));
        }
     }
   
@@ -3781,7 +3781,7 @@ nvptx_sese_pseudo (basic_block me, bb_se
   if (!sese->brackets.length () || !edges || !edges->length ())
     {
       hi_back = 0;
-      node_back = pseudo_node_t (0, 0);
+      node_back = pseudo_node_t (nullptr, 0);
       sese->push (node_back);
     }
 

        Jakub