[gcc r14-4864] ipa/111914 - perform parameter init after remapping types

[Richard Biener <rguenth@gcc.gnu.org>]

https://gcc.gnu.org/g:738d44348e7392a9f8e370afa3a9d8c24ee080cd

commit r14-4864-g738d44348e7392a9f8e370afa3a9d8c24ee080cd
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Oct 23 13:29:30 2023 +0200

    ipa/111914 - perform parameter init after remapping types
    
    The following addresses a mismatch in SSA name vs. symbol when
    we emit a dummy assignment when not optimizing.  The temporary
    we create is not remapped by initialize_inlined_parameters because
    we have no easy way to get at it.  The following instead emits
    the additional statement after we have remapped the type of
    the replacement variable.
    
            PR ipa/111914
            * tree-inline.cc (setup_one_parameter): Move code emitting
            a dummy load when not optimizing ...
            (initialize_inlined_parameters): ... here to after when
            we remapped the parameter type.
    
            * gcc.dg/pr111914.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.dg/pr111914.c | 14 ++++++++++++++
 gcc/tree-inline.cc              | 26 ++++++++++++++++++--------
 2 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/pr111914.c b/gcc/testsuite/gcc.dg/pr111914.c
new file mode 100644
index 000000000000..05804bddcb9f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr111914.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99" } */
+
+__attribute__((always_inline))
+static inline void f(int n, int (*a())[n])
+{
+  /* Unused 'a'.  */
+}
+
+void g(void)
+{
+  int (*a())[1];
+  f(1, a);
+}
diff --git a/gcc/tree-inline.cc b/gcc/tree-inline.cc
index d63060c9429c..69387b525f9e 100644
--- a/gcc/tree-inline.cc
+++ b/gcc/tree-inline.cc
@@ -3578,9 +3578,7 @@ setup_one_parameter (copy_body_data *id, tree p, tree value, tree fn,
 
       STRIP_USELESS_TYPE_CONVERSION (rhs);
 
-      /* If we are in SSA form properly remap the default definition
-         or assign to a dummy SSA name if the parameter is unused and
-	 we are not optimizing.  */
+      /* If we are in SSA form properly remap the default definition.  */
       if (gimple_in_ssa_p (cfun) && is_gimple_reg (p))
 	{
 	  if (def)
@@ -3590,11 +3588,6 @@ setup_one_parameter (copy_body_data *id, tree p, tree value, tree fn,
 	      SSA_NAME_IS_DEFAULT_DEF (def) = 0;
 	      set_ssa_default_def (cfun, var, NULL);
 	    }
-	  else if (!optimize)
-	    {
-	      def = make_ssa_name (var);
-	      init_stmt = gimple_build_assign (def, rhs);
-	    }
 	}
       else if (!is_empty_type (TREE_TYPE (var)))
         init_stmt = gimple_build_assign (var, rhs);
@@ -3653,6 +3646,23 @@ initialize_inlined_parameters (copy_body_data *id, gimple *stmt,
 		  && SSA_NAME_VAR (*defp) == var)
 		TREE_TYPE (*defp) = TREE_TYPE (var);
 	    }
+	  /* When not optimizing and the parameter is unused, assign to
+	     a dummy SSA name.  Do this after remapping the type above.  */
+	  else if (!optimize
+		   && is_gimple_reg (p)
+		   && i < gimple_call_num_args (stmt))
+	    {
+	      tree val = gimple_call_arg (stmt, i);
+	      if (val != error_mark_node)
+		{
+		  if (!useless_type_conversion_p (TREE_TYPE (p),
+						  TREE_TYPE (val)))
+		    val = force_value_to_type (TREE_TYPE (p), val);
+		  def = make_ssa_name (var);
+		  gimple *init_stmt = gimple_build_assign (def, val);
+		  insert_init_stmt (id, bb, init_stmt);
+		}
+	    }
 	}
     }