mem: fix page_table bug for .fast build

Since b8b13206c8, the '.fast' build has failed to compile with an error
caused by a variable and an assert.

As a reminder, assert macros are optimized out of the build for '.fast'.
If an assert check requires a variable that is unused anywhere else in
the code, the compiler complains that the variable is unused and the
scons build fails. The solution is to add a M5_VAR_USED specifier to
tell the compiler to ignore the variable.

Change-Id: I38f6bbed1e4c0506c5bbc1206c21f1f7e3d8dfe6
Reviewed-on: https://gem5-review.googlesource.com/8462
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/mem/page_table.cc b/src/mem/page_table.cc
index cd3422560..d771479d0 100644
--- a/src/mem/page_table.cc
+++ b/src/mem/page_table.cc
@@ -39,6 +39,7 @@
 
 #include <string>
 
+#include "base/compiler.hh"
 #include "base/trace.hh"
 #include "debug/MMU.hh"
 #include "sim/faults.hh"
@@ -83,7 +84,7 @@ EmulationPageTable::remap(Addr vaddr, int64_t size, Addr new_vaddr)
             new_vaddr, size);
 
     while (size > 0) {
-        auto new_it = pTable.find(new_vaddr);
+        auto new_it M5_VAR_USED = pTable.find(new_vaddr);
         auto old_it = pTable.find(vaddr);
         assert(old_it != pTable.end() && new_it == pTable.end());