[gcc r16-1249] Avoid useless reading of profile data in LTO

[Jan Hubicka]

https://gcc.gnu.org/g:572dd0dd8db4bec69883c0b3e53013a7842e886e

commit r16-1249-g572dd0dd8db4bec69883c0b3e53013a7842e886e
Author: Jan Hubicka <hubicka@ucw.cz>
Date:   Fri Jun 6 10:56:51 2025 +0200

    Avoid useless reading of profile data in LTO
    
    New auto-profile merging dumps made me notice that we read the afdo
    data when we are in LTO.  This is not necessary since profile is read
    at compile time and streamed to LTO bytecode.
    
    gcc/ChangeLog:
    
            * coverage.cc (coverage_init): Return early when in LTO

Diff:
---
 gcc/coverage.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gcc/coverage.cc b/gcc/coverage.cc
index 7181e7573594..c0ae76a40ef1 100644
--- a/gcc/coverage.cc
+++ b/gcc/coverage.cc
@@ -1253,6 +1253,9 @@ coverage_obj_finish (vec<constructor_elt, va_gc> *ctor,
 void
 coverage_init (const char *filename)
 {
+  /* If we are in LTO, the profile will be read from object files.  */
+  if (in_lto_p)
+    return;
   const char *original_filename = filename;
   int original_len = strlen (original_filename);
 #if HAVE_DOS_BASED_FILE_SYSTEM