re PR tree-optimization/42917 ("-fcompare-debug failure" with -ftree-loop-linear)

        PR tree-optimization/42917
        * lambda-code.c (remove_iv): Skip debug statements.
        (lambda_loopnest_to_gcc_loopnest): Likewise.
        (not_interesting_stmt): Debug statements are not interesting.


Co-Authored-By: Alexandre Oliva <aoliva@redhat.com>

From-SVN: r157477

gcc/ChangeLog

+2010-03-16  Aldy Hernandez  <aldyh@redhat.com>
+	    Alexandre Oliva  <aoliva@redhat.com>
+
+	PR tree-optimization/42917
+	* lambda-code.c (remove_iv): Skip debug statements.
+	(lambda_loopnest_to_gcc_loopnest): Likewise.
+	(not_interesting_stmt): Debug statements are not interesting.
+
 2010-03-16  Jakub Jelinek  <jakub@redhat.com>
 
 	PR debug/43051

gcc/lambda-code.c

@@ -1657,7 +1657,7 @@ remove_iv (gimple iv_stmt)
 	    continue;
 
 	  FOR_EACH_IMM_USE_STMT (stmt, imm_iter, arg)
-	    if (stmt != iv_stmt)
+	    if (stmt != iv_stmt && !is_gimple_debug (stmt))
 	      used = true;
 
 	  if (!used)
@@ -1839,6 +1839,9 @@ lambda_loopnest_to_gcc_loopnest (struct loop *old_loopnest,
 	  gimple_seq stmts;
 	  lambda_body_vector lbv, newlbv;
 
+	  if (is_gimple_debug (stmt))
+	    continue;
+
 	  /* Compute the new expression for the induction
 	     variable.  */
 	  depth = VEC_length (tree, new_ivs);
@@ -1885,7 +1888,8 @@ not_interesting_stmt (gimple stmt)
      loop, we would have already failed the number of exits tests.  */
   if (gimple_code (stmt) == GIMPLE_LABEL
       || gimple_code (stmt) == GIMPLE_GOTO
-      || gimple_code (stmt) == GIMPLE_COND)
+      || gimple_code (stmt) == GIMPLE_COND
+      || is_gimple_debug (stmt))
     return true;
   return false;
 }

gcc/testsuite/gcc.dg/pr42917.c

+/* { dg-do compile } */
+/* { dg-options "-O1 -ftree-loop-linear -fcompare-debug -fdump-tree-ltrans" } */
+
+extern int A[];
+
+void
+foo ()
+{
+  int i, j;
+  for (i = 0; i < 4; i++)
+    for (j = 255; j >= 0; j--)
+      A[j] = 0;
+}
+
+/* { dg-final { scan-tree-dump "Successfully transformed loop" "ltrans" } } */
+/* { dg-final { cleanup-tree-dump "ltrans" } } */