From 4c94382a132a4b2b9d020806549a006fa6764d1b Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Fri, 1 Jul 2022 14:11:35 +0200
Subject: [PATCH] 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.
---
 gcc/config/i386/i386-options.cc       | 32 ++++++++++--------------
 gcc/testsuite/gcc.dg/lto/pr105459_0.c | 35 +++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 19 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/lto/pr105459_0.c

diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
index e11f68186f5..acb2291e70f 100644
--- a/gcc/config/i386/i386-options.cc
+++ b/gcc/config/i386/i386-options.cc
@@ -3232,28 +3232,22 @@ 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
index 00000000000..c799e6ef23d
--- /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;
+}