rs6000: Handle unresolved overloaded builtin [PR105485]

PR105485 exposes that new builtin function framework doesn't handle
unresolved overloaded builtin function well.  With new builtin
function support, we don't have builtin info for any overloaded
rs6000_gen_builtins enum, since they are expected to be resolved to
one specific instance.  So when function rs6000_gimple_fold_builtin
faces one unresolved overloaded builtin, the access for builtin info
becomes out of bound and gets ICE then.

We should not try to fold one unresolved overloaded builtin there
and as the previous support we should emit one error message during
expansion phase like "unresolved overload for builtin ...".

	PR target/105485

gcc/ChangeLog:

	* config/rs6000/rs6000-builtin.cc (rs6000_gimple_fold_builtin): Add
	the handling for unresolved overloaded builtin function.
	(rs6000_expand_builtin): Likewise.

gcc/testsuite/ChangeLog:

	* g++.target/powerpc/pr105485.C: New test.

1 files changed, 13 insertions, 0 deletions

diff --git a/gcc/config/rs6000/rs6000-builtin.cc b/gcc/config/rs6000/rs6000-builtin.cc
index 6dfb0db..3ce729c 100644
--- a/gcc/config/rs6000/rs6000-builtin.cc
+++ b/gcc/config/rs6000/rs6000-builtin.cc
@@ -1260,6 +1260,11 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
   enum tree_code bcode;
   gimple *g;
 
+  /* For an unresolved overloaded builtin, return early here since there
+     is no builtin info for it and we are unable to fold it.  */
+  if (fn_code > RS6000_OVLD_NONE)
+    return false;
+
   size_t uns_fncode = (size_t) fn_code;
   enum insn_code icode = rs6000_builtin_info[uns_fncode].icode;
   const char *fn_name1 = rs6000_builtin_info[uns_fncode].bifname;
@@ -3256,6 +3261,14 @@ rs6000_expand_builtin (tree exp, rtx target, rtx /* subtarget */,
   tree fndecl = TREE_OPERAND (CALL_EXPR_FN (exp), 0);
   enum rs6000_gen_builtins fcode
     = (enum rs6000_gen_builtins) DECL_MD_FUNCTION_CODE (fndecl);
+
+  /* Emit error message if it's an unresolved overloaded builtin.  */
+  if (fcode > RS6000_OVLD_NONE)
+    {
+      error ("unresolved overload for builtin %qF", fndecl);
+      return const0_rtx;
+    }
+
   size_t uns_fcode = (size_t)fcode;
   enum insn_code icode = rs6000_builtin_info[uns_fcode].icode;