* gimplify.c (gimplify_switch_expr): Also handle GIMPLE_TRY.

	* c-c++-common/Wswitch-unreachable-3.c: New test.
	* g++.dg/warn/Wswitch-unreachable-1.C: New test.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@236924 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 82 insertions, 3 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a558a944e5b..59aae29bdc4 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2016-05-31  Marek Polacek  <polacek@redhat.com>
+
+	* gimplify.c (gimplify_switch_expr): Also handle GIMPLE_TRY.
+
 2016-05-31  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* config/aarch64/aarch64.c (aarch_macro_fusion_pair_p): Use
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 8316bb8881f..8b7dddca48a 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -1609,10 +1609,17 @@ gimplify_switch_expr (tree *expr_p, gimple_seq *pre_p)
 	  while (gimple_code (seq) == GIMPLE_BIND)
 	    seq = gimple_bind_body (as_a <gbind *> (seq));
 	  gimple *stmt = gimple_seq_first_stmt (seq);
-	  enum gimple_code code = gimple_code (stmt);
-	  if (code != GIMPLE_LABEL && code != GIMPLE_TRY)
+	  if (gimple_code (stmt) == GIMPLE_TRY)
 	    {
-	      if (code == GIMPLE_GOTO
+	      /* A compiler-generated cleanup or a user-written try block.
+		 Try to get the first statement in its try-block, for better
+		 location.  */
+	      if ((seq = gimple_try_eval (stmt)))
+		stmt = gimple_seq_first_stmt (seq);
+	    }
+	  if (gimple_code (stmt) != GIMPLE_LABEL)
+	    {
+	      if (gimple_code (stmt) == GIMPLE_GOTO
 		  && TREE_CODE (gimple_goto_dest (stmt)) == LABEL_DECL
 		  && DECL_ARTIFICIAL (gimple_goto_dest (stmt)))
 		/* Don't warn for compiler-generated gotos.  These occur
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8c5def43270..a7cf8340d15 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-05-31  Marek Polacek  <polacek@redhat.com>
+
+	* c-c++-common/Wswitch-unreachable-3.c: New test.
+	* g++.dg/warn/Wswitch-unreachable-1.C: New test.
+
 2016-05-31  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/71352
diff --git a/gcc/testsuite/c-c++-common/Wswitch-unreachable-3.c b/gcc/testsuite/c-c++-common/Wswitch-unreachable-3.c
new file mode 100644
index 00000000000..c53cb106b21
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Wswitch-unreachable-3.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+
+extern void f (int *);
+
+void
+g (int i)
+{
+  switch (i)
+    {
+      int a[3];
+      __builtin_memset (a, 0, sizeof a); /* { dg-warning "statement will never be executed" } */
+
+    default:
+      f (a);
+    }
+
+  switch (i)
+    {
+      int a[3];
+      int b[3];
+      int c[3];
+      b[1] = 60; /* { dg-warning "statement will never be executed" } */
+
+    default:
+      f (a);
+      f (b);
+      f (c);
+    }
+}
diff --git a/gcc/testsuite/g++.dg/warn/Wswitch-unreachable-1.C b/gcc/testsuite/g++.dg/warn/Wswitch-unreachable-1.C
new file mode 100644
index 00000000000..99d9a833217
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wswitch-unreachable-1.C
@@ -0,0 +1,34 @@
+// { dg-do compile }
+
+extern int j;
+
+void
+f (int i)
+{
+  switch (i) // { dg-warning "statement will never be executed" }
+    {
+      try
+      {
+      }
+      catch (...)
+      {
+      }
+    case 1:;
+    }
+}
+
+void
+g (int i)
+{
+  switch (i)
+    {
+      try
+      {
+	j = 42;  // { dg-warning "statement will never be executed" }
+      }
+      catch (...)
+      {
+      }
+    case 1:;
+    }
+}