[PATCH] Fix call-cdce (PR tree-optimization/37353)

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

The testcase below ICEs, because tree-call-cdce.c VEC_alloc a 64 entry
vector and then VEC_quick_pushes all the call-cdce candidate GIMPLE_CALLs
into it, which obviously breaks if there are more than 64 such calls.

While it could be fixed just by using VEC_safe_push instead of
VEC_quick_push, while touching it I took the liberty to do a few cleanups as
well - I see no reason why we need to use a global variable for the vector,
and we can/should IMHO in the common case when there are no such calls in
the whole function save a heap VEC_alloc/VEC_free.

Bootstrapped/regtested on x86_64-linux, ok for trunk?

2008-09-09  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/37353
	* tree-call-cdce.c (cond_dead_built_in_calls): Remove.
	(shrink_wrap_conditional_dead_built_in_calls): Add calls argument, use
	calls instead of cond_dead_built_in_calls.
	(tree_call_cdce): Add cond_dead_built_in_calls automatic variable,
	initalize the vector only before adding first entry.  Use VEC_safe_push
	instead of VEC_quick_push.  Pass cond_dead_built_in_calls to
	shrink_wrap_conditional_dead_built_in_calls call.

	* gcc.dg/pr37353.c: New test.

--- gcc/tree-call-cdce.c.jj	2008-09-05 12:56:32.000000000 +0200
+++ gcc/tree-call-cdce.c	2008-09-09 21:50:23.000000000 +0200
@@ -99,8 +99,6 @@ typedef struct input_domain
   bool is_ub_inclusive;
 } inp_domain;
 
-static VEC (gimple, heap) *cond_dead_built_in_calls;
-
 /* A helper function to construct and return an input
    domain object.  LB is the lower bound, HAS_LB is 
    a boolean flag indicating if the lower bound exists,
@@ -844,18 +842,18 @@ shrink_wrap_one_built_in_call (gimple bi
    wrapping transformation.  */
 
 static bool
-shrink_wrap_conditional_dead_built_in_calls (void)
+shrink_wrap_conditional_dead_built_in_calls (VEC (gimple, heap) *calls)
 {
   bool changed = false;
   unsigned i = 0;
 
-  unsigned n = VEC_length (gimple, cond_dead_built_in_calls);
+  unsigned n = VEC_length (gimple, calls);
   if (n == 0) 
     return false;
 
   for (; i < n ; i++)
     {
-      gimple bi_call = VEC_index (gimple, cond_dead_built_in_calls, i);
+      gimple bi_call = VEC_index (gimple, calls, i);
       changed |= shrink_wrap_one_built_in_call (bi_call);
     }
 
@@ -870,8 +868,7 @@ tree_call_cdce (void)
   basic_block bb;
   gimple_stmt_iterator i;
   bool something_changed = false;
-  cond_dead_built_in_calls = VEC_alloc (gimple, heap, 64);
-
+  VEC (gimple, heap) *cond_dead_built_in_calls = NULL;
   FOR_EACH_BB (bb)
     {
       /* Collect dead call candidates.  */
@@ -887,12 +884,18 @@ tree_call_cdce (void)
                   print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
                   fprintf (dump_file, "\n");
                 }
-              VEC_quick_push (gimple, cond_dead_built_in_calls, stmt);
+	      if (cond_dead_built_in_calls == NULL)
+		cond_dead_built_in_calls = VEC_alloc (gimple, heap, 64);
+	      VEC_safe_push (gimple, heap, cond_dead_built_in_calls, stmt);
             }
 	}
     }
 
-  something_changed = shrink_wrap_conditional_dead_built_in_calls ();
+  if (cond_dead_built_in_calls == NULL)
+    return 0;
+
+  something_changed
+    = shrink_wrap_conditional_dead_built_in_calls (cond_dead_built_in_calls);
 
   VEC_free (gimple, heap, cond_dead_built_in_calls);
 
--- gcc/testsuite/gcc.dg/pr37353.c.jj	2008-09-09 21:32:16.000000000 +0200
+++ gcc/testsuite/gcc.dg/pr37353.c	2008-09-09 21:31:59.000000000 +0200
@@ -0,0 +1,15 @@
+/* PR tree-optimization/37353 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+extern double exp (double);
+
+#define A exp (arg);
+#define B A A A A A A A A A A
+#define C B B B B B B B B B B
+
+void
+foo (double arg)
+{
+  C
+}

	Jakub