target/105459 - allow delayed target option node fixup

The following avoids the need to massage the target optimization
node at WPA time when we fixup the optimization node, copying
FP related flags from callee to caller.  The target is already
set up to fixup, but that only works when not switching between
functions.  After fixing that the fixup is then done at LTRANS
time when materializing the function.

2022-07-01  Richard Biener  <rguenthert@suse.de>

	PR target/105459
	* config/i386/i386-options.cc (ix86_set_current_function):
	Rebuild the target optimization node whenever necessary,
	not only when the optimization node didn't change.

	* gcc.dg/lto/pr105459_0.c: New testcase.

(cherry picked from commit 4c94382a132a4b2b9d020806549a006fa6764d1b)

diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
index 32cc58a764b37ca99394246ac0844b7fe17e36c1..706be5a60b81ba3c7bd1bc5095692edf877dd189 100644 (file)
--- a/gcc/config/i386/i386-options.cc
+++ b/gcc/config/i386/i386-options.cc
@@ -3229,28 +3229,22 @@ ix86_set_current_function (tree fndecl)
   if (new_tree == NULL_TREE)
     new_tree = target_option_default_node;
 
-  if (old_tree != new_tree)
+  bool fp_flag_change
+    = (flag_unsafe_math_optimizations
+       != TREE_TARGET_OPTION (new_tree)->x_ix86_unsafe_math_optimizations
+       || (flag_excess_precision
+          != TREE_TARGET_OPTION (new_tree)->x_ix86_excess_precision));
+  if (old_tree != new_tree || fp_flag_change)
     {
       cl_target_option_restore (&global_options, &global_options_set,
                                TREE_TARGET_OPTION (new_tree));
-      if (TREE_TARGET_GLOBALS (new_tree))
-       restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
-      else if (new_tree == target_option_default_node)
-       restore_target_globals (&default_target_globals);
-      else
-       TREE_TARGET_GLOBALS (new_tree) = save_target_globals_default_opts ();
-    }
-  else if (flag_unsafe_math_optimizations
-          != TREE_TARGET_OPTION (new_tree)->x_ix86_unsafe_math_optimizations
-          || (flag_excess_precision
-              != TREE_TARGET_OPTION (new_tree)->x_ix86_excess_precision))
-    {
-      cl_target_option_restore (&global_options, &global_options_set,
-                               TREE_TARGET_OPTION (new_tree));
-      ix86_excess_precision = flag_excess_precision;
-      ix86_unsafe_math_optimizations = flag_unsafe_math_optimizations;
-      DECL_FUNCTION_SPECIFIC_TARGET (fndecl) = new_tree
-       = build_target_option_node (&global_options, &global_options_set);
+      if (fp_flag_change)
+       {
+         ix86_excess_precision = flag_excess_precision;
+         ix86_unsafe_math_optimizations = flag_unsafe_math_optimizations;
+         DECL_FUNCTION_SPECIFIC_TARGET (fndecl) = new_tree
+           = build_target_option_node (&global_options, &global_options_set);
+       }
       if (TREE_TARGET_GLOBALS (new_tree))
        restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
       else if (new_tree == target_option_default_node)

diff --git a/gcc/testsuite/gcc.dg/lto/pr105459_0.c b/gcc/testsuite/gcc.dg/lto/pr105459_0.c
new file mode 100644 (file)
index 0000000..c799e6e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr105459_0.c
@@ -0,0 +1,35 @@
+/* { dg-lto-do link } */
+/* { dg-lto-options { { -flto -O1 } } } */
+
+double m;
+int n;
+
+__attribute__ ((optimize ("-funsafe-math-optimizations")))
+void
+bar (int x)
+{
+  n = x;
+  m = n;
+}
+
+__attribute__ ((flatten))
+void
+foo (int x)
+{
+  bar (x);
+}
+
+void
+quux (void)
+{
+  ++n;
+}
+
+int
+main (void)
+{
+  foo (0);
+  quux ();
+
+  return 0;
+}