gimple-fold: fix further missing stmt locations [PR104308]

PR analyzer/104308 initially reported about a
-Wanalyzer-use-of-uninitialized-value diagnostic using UNKNOWN_LOCATION
when complaining about certain memmove operations where the source
is uninitialized.

In r12-7856-g875342766d4298 I fixed the missing location for
a stmt generated by gimple_fold_builtin_memory_op, but the reporter
then found another way to generate such a stmt with UNKNOWN_LOCATION.

I've now gone through gimple_fold_builtin_memory_op looking at all
statement creation, and found three places in which a new statement
doesn't have a location set on it (either directly via
gimple_set_location, or indirectly via gsi_replace), one of which is
the new reproducer.

This patch adds a gimple_set_location to these three cases, and adds
test coverage for one of them (the third hunk within the patch), fixing
the new reproducer for PR analyzer/104308.

gcc/ChangeLog:
	PR analyzer/104308
	* gimple-fold.cc (gimple_fold_builtin_memory_op): Explicitly set
	the location of new_stmt in all places that don't already set it,
	whether explicitly, or via a call to gsi_replace.

gcc/testsuite/ChangeLog:
	PR analyzer/104308
	* gcc.dg/analyzer/pr104308.c: Add test coverage.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
index ac22adf..863ee3d 100644
--- a/gcc/gimple-fold.cc
+++ b/gcc/gimple-fold.cc
@@ -1048,6 +1048,7 @@ gimple_fold_builtin_memory_op (gimple_stmt_iterator *gsi,
 			  gsi_replace (gsi, new_stmt, false);
 			  return true;
 			}
+		      gimple_set_location (new_stmt, loc);
 		      gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
 		      goto done;
 		    }
@@ -1302,6 +1303,7 @@ gimple_fold_builtin_memory_op (gimple_stmt_iterator *gsi,
 						   new_stmt);
 	      gimple_assign_set_lhs (new_stmt, srcvar);
 	      gimple_set_vuse (new_stmt, gimple_vuse (stmt));
+	      gimple_set_location (new_stmt, loc);
 	      gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
 	    }
 	  new_stmt = gimple_build_assign (destvar, srcvar);
@@ -1338,6 +1340,7 @@ set_vop_and_replace:
 	  gsi_replace (gsi, new_stmt, false);
 	  return true;
 	}
+      gimple_set_location (new_stmt, loc);
       gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
     }