[gcc r12-8777] rs6000: Handle unresolved overloaded builtin [PR105485]

[gcc r12-8777] rs6000: Handle unresolved overloaded builtin [PR105485]

[Kewen Lin]

https://gcc.gnu.org/g:104864f99c07f87b53c7f45c50a1991b21249489

commit r12-8777-g104864f99c07f87b53c7f45c50a1991b21249489
Author: Kewen.Lin <linkw@gcc.gnu.org>
Date:   Tue Sep 13 04:13:59 2022 -0500

    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.
    
    (cherry picked from commit 94504c9ae157db937a2e62d533a36d56598f3c09)

Diff:
---
 gcc/config/rs6000/rs6000-builtin.cc         | 13 +++++++++++++
 gcc/testsuite/g++.target/powerpc/pr105485.C |  9 +++++++++
 2 files changed, 22 insertions(+)

diff --git a/gcc/config/rs6000/rs6000-builtin.cc b/gcc/config/rs6000/rs6000-builtin.cc
index 15370e45e65..26b486a9e5d 100644
--- a/gcc/config/rs6000/rs6000-builtin.cc
+++ b/gcc/config/rs6000/rs6000-builtin.cc
@@ -1299,6 +1299,11 @@ 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;
@@ -3300,6 +3305,14 @@ 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;
 
diff --git a/gcc/testsuite/g++.target/powerpc/pr105485.C b/gcc/testsuite/g++.target/powerpc/pr105485.C
new file mode 100644
index 00000000000..db1bd944aae
--- /dev/null
+++ b/gcc/testsuite/g++.target/powerpc/pr105485.C
@@ -0,0 +1,9 @@
+/* It's to verify no ICE here, ignore error/warning messages
+   since they are not test points here.  */
+/* { dg-excess-errors "pr105485" } */
+
+template <class> void __builtin_vec_vslv();
+typedef  __attribute__((altivec(vector__))) char T;
+T b (T c, T d) {
+    return __builtin_vec_vslv(c, d);
+}