Re: [PATCH] Fix PR56426

[Tom de Vries]

On 25-02-13 20:53, Marek Polacek wrote:
2013-02-25  Marek Polacek  <pola...@redhat.com>
        PR tree-optimization/56426
        * tree-ssa-loop.c (tree_ssa_loop_init): Always call
        scev_initialize.

        * gcc.dg/pr56436.c: New test.

--- gcc/tree-ssa-loop.c.mp      2013-02-25 13:06:47.212132327 +0100
+++ gcc/tree-ssa-loop.c 2013-02-25 20:09:30.668978936 +0100
@@ -70,10 +70,13 @@ tree_ssa_loop_init (void)
                       | LOOPS_HAVE_RECORDED_EXITS);
    rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);

+  /* We might discover new loops, e.g. when turning irreducible
+     regions into reducible.  */
+  scev_initialize ();
+
    if (number_of_loops () <= 1)
      return 0;

-  scev_initialize ();
    return 0;
  }


Marek,

moving scev_initialize up leaves the if-clause as dead code. This patches 
removes that dead code. Bootstrapped and reg-tested with tree-ssa.exp.

Committed as trivial.

Thanks,
- Tom

2014-07-30  Tom de Vries  <t...@codesourcery.com>

	* tree-ssa-loop.c (pass_tree_loop_init::execute): Remove dead code.

diff --git a/gcc/tree-ssa-loop.c b/gcc/tree-ssa-loop.c
index 7c52748..d0c9980 100644
--- a/gcc/tree-ssa-loop.c
+++ b/gcc/tree-ssa-loop.c
@@ -168,7 +168,7 @@ public:
 }; // class pass_tree_loop_init
 
 unsigned int
-pass_tree_loop_init::execute (function *fun)
+pass_tree_loop_init::execute (function *fun ATTRIBUTE_UNUSED)
 {
   loop_optimizer_init (LOOPS_NORMAL
 		       | LOOPS_HAVE_RECORDED_EXITS);
@@ -178,9 +178,6 @@ pass_tree_loop_init::execute (function *fun)
      regions into reducible.  */
   scev_initialize ();
 
-  if (number_of_loops (fun) <= 1)
-    return 0;
-
   return 0;
 }