Go patch committed: Turn off -fipa-icf-functions

[Ian Lance Taylor via Gcc-patches]

Go code expects to be able to do a reliable backtrace and get correct
file/line information of callers.  This is broken by
-fipa-icf-functions, so this Go frontend patch disables that option by
default.  Bootstrapped and ran Go testsuite on x86_64-pc-linux-gnu.
Committed to mainline.

Ian

* go-lang.c (go_langhook_post_options): Disable
-fipa-icf-functions if it was not explicitly enabled.

diff --git a/gcc/go/go-lang.c b/gcc/go/go-lang.c
index 2cfb41042bd..08c1f38a2c1 100644
--- a/gcc/go/go-lang.c
+++ b/gcc/go/go-lang.c
@@ -306,6 +306,12 @@ go_langhook_post_options (const char **pfilename 
ATTRIBUTE_UNUSED)
   SET_OPTION_IF_UNSET (&global_options, &global_options_set,
                       flag_partial_inlining, 0);
 
+  /* Go programs expect runtime.Callers to give the right answers,
+     which means that we can't combine functions even if they look the
+     same.  */
+  SET_OPTION_IF_UNSET (&global_options, &global_options_set,
+                      flag_ipa_icf_functions, 0);
+
   /* If the debug info level is still 1, as set in init_options, make
      sure that some debugging type is selected.  */
   if (global_options.x_debug_info_level == DINFO_LEVEL_TERSE