When niter may be zero, return a COND_EXPR with the may_be_zero condition.

2010-05-28  Sebastian Pop  <sebastian.pop@amd.com>

	* tree-scalar-evolution.c (set_nb_iterations_in_loop): Inlined in the
	only place it was called from.
	(number_of_latch_executions): Do not return chrec_dont_know when the
	may_be_zero is a runtime condition: instead, return a COND_EXPR
	including the may_be_zero condition.
	* cfgloop.h (struct loop): Add a note on COND_EXPRs to the comment
	of nb_iterations.
	* tree-ssa-loop-ivopts.c (contains_abnormal_ssa_name_p): Handle
	COND_EXPRs.

	* gcc.dg/vect/vect-outer-fir-lb.c: Un-XFAIL-ed.

From-SVN: r159992

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d2d4f2db3bbca363bec735cd0b780ca5e8637a69..5b083fd4d7bcafa2c135b0f43c4633a7a3697cd3 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2010-05-28  Sebastian Pop  <sebastian.pop@amd.com>
+
+       * tree-scalar-evolution.c (set_nb_iterations_in_loop): Inlined in the
+       only place it was called from.
+       (number_of_latch_executions): Do not return chrec_dont_know when the
+       may_be_zero is a runtime condition: instead, return a COND_EXPR
+       including the may_be_zero condition.
+       * cfgloop.h (struct loop): Add a note on COND_EXPRs to the comment
+       of nb_iterations.
+       * tree-ssa-loop-ivopts.c (contains_abnormal_ssa_name_p): Handle
+       COND_EXPRs.
+
 2010-05-28  Sebastian Pop  <sebastian.pop@amd.com>
 
        * tree-if-conv.c (replace_phi_with_cond_gimple_assign_stmt): Don't

diff --git a/gcc/cfgloop.h b/gcc/cfgloop.h
index 96911c6a4150e5cdfa5f440f819c5d1fcae402eb..3821ee66c7993d74e4591333baee45e357d84d30 100644 (file)
--- a/gcc/cfgloop.h
+++ b/gcc/cfgloop.h
@@ -134,11 +134,13 @@ struct GTY ((chain_next ("%h.next"))) loop {
   /* Auxiliary info specific to a pass.  */
   PTR GTY ((skip (""))) aux;
 
-  /* The number of times the latch of the loop is executed.
-     This is an INTEGER_CST or an expression containing symbolic
-     names.  Don't access this field directly:
-     number_of_latch_executions computes and caches the computed
-     information in this field.  */
+  /* The number of times the latch of the loop is executed.  This can be an
+     INTEGER_CST, or a symbolic expression representing the number of
+     iterations like "N - 1", or a COND_EXPR containing the runtime
+     conditions under which the number of iterations is non zero.
+
+     Don't access this field directly: number_of_latch_executions
+     computes and caches the computed information in this field.  */
   tree nb_iterations;
 
   /* An integer guaranteed to bound the number of iterations of the loop

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b41e4be73d950c9d181f62ece2cc6cca7b97587a..c5b13d632220ea23815043c273464c3f5dbb99ec 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2010-05-28  Sebastian Pop  <sebastian.pop@amd.com>
+
+       * gcc.dg/vect/vect-outer-fir-lb.c: Un-XFAIL-ed.
+
 2010-05-28  Mike Stump  <mikestump@comcast.net>
 
        PR objc/44125
@@ -40,7 +44,7 @@
        * obj-c++.dg/torture/tls/thr-init-2.mm: Ditto.
        * obj-c++.dg/torture/tls/thr-init-3.mm: Ditto.
        * obj-c++.dg/torture/trivial.mm: Ditto.
-       
+
 2010-05-27  Jack Howarth  <howarth@bromo.med.uc.edu>
 
        * g++.dg/lto/20100302_0.C: Skip on darwin.

diff --git a/gcc/testsuite/gcc.dg/vect/vect-outer-fir-lb.c b/gcc/testsuite/gcc.dg/vect/vect-outer-fir-lb.c
index bdc07f9af76b508e33c817592fc171392a6572be..3c1a362c003e741eeb686c1f84ca8d80797c860c 100644 (file)
--- a/gcc/testsuite/gcc.dg/vect/vect-outer-fir-lb.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-outer-fir-lb.c
@@ -10,10 +10,7 @@ float coeff[M];
 float out[N];
 float fir_out[N];
 
-/* Should be vectorized. Fixed misaligment in the inner-loop.  */
-/* Currently not vectorized because the loop-count for the inner-loop
-   has a maybe_zero component. Will be fixed when we incorporate the
-   "cond_expr in rhs" patch.  */
+/* Vectorized.  Fixed misaligment in the inner-loop.  */
 __attribute__ ((noinline))
 void foo (){
  int i,j,k;
@@ -30,7 +27,7 @@ void foo (){
 
     do {
       diff += in[j+i]*coeff[j];
-      j+=4;    
+      j+=4;
     } while (j < M);
 
     out[i] += diff;
@@ -39,7 +36,7 @@ void foo (){
 
 }
 
-/* Vectorized. Changing misalignment in the inner-loop.  */
+/* Vectorized.  Changing misalignment in the inner-loop.  */
 __attribute__ ((noinline))
 void fir (){
   int i,j,k;
@@ -68,7 +65,7 @@ int main (void)
 
   foo ();
   fir ();
-  
+
   for (i = 0; i < N; i++) {
     if (out[i] != fir_out[i])
       abort ();
@@ -77,6 +74,5 @@ int main (void)
   return 0;
 }
 
-/* { dg-final { scan-tree-dump-times "OUTER LOOP VECTORIZED" 2 "vect" { xfail *-*-* } } } */
-/* { dg-final { scan-tree-dump-times "OUTER LOOP VECTORIZED" 1 "vect" { xfail vect_no_align } } } */
+/* { dg-final { scan-tree-dump-times "OUTER LOOP VECTORIZED" 2 "vect" { xfail vect_no_align } } } */
 /* { dg-final { cleanup-tree-dump "vect" } } */

diff --git a/gcc/tree-scalar-evolution.c b/gcc/tree-scalar-evolution.c
index e2ed1f59ee2c9ddf87c53b36b977cfca4191e9be..d50eac9833948e44181ca80c6518d6ce3f702622 100644 (file)
--- a/gcc/tree-scalar-evolution.c
+++ b/gcc/tree-scalar-evolution.c
@@ -900,23 +900,6 @@ add_to_evolution (unsigned loop_nb, tree chrec_before, enum tree_code code,
   return res;
 }
 
-/* Helper function.  */
-
-static inline tree
-set_nb_iterations_in_loop (struct loop *loop,
-                          tree res)
-{
-  if (dump_file && (dump_flags & TDF_DETAILS))
-    {
-      fprintf (dump_file, "  (set_nb_iterations_in_loop = ");
-      print_generic_expr (dump_file, res, 0);
-      fprintf (dump_file, "))\n");
-    }
-
-  loop->nb_iterations = res;
-  return res;
-}
-
 \f
 
 /* This section selects the loops that will be good candidates for the
@@ -2685,8 +2668,11 @@ resolve_mixers (struct loop *loop, tree chrec)
 /* Entry point for the analysis of the number of iterations pass.
    This function tries to safely approximate the number of iterations
    the loop will run.  When this property is not decidable at compile
-   time, the result is chrec_dont_know.  Otherwise the result is
-   a scalar or a symbolic parameter.
+   time, the result is chrec_dont_know.  Otherwise the result is a
+   scalar or a symbolic parameter.  When the number of iterations may
+   be equal to zero and the property cannot be determined at compile
+   time, the result is a COND_EXPR that represents in a symbolic form
+   the conditions under which the number of iterations is not zero.
 
    Example of analysis: suppose that the loop has an exit condition:
 
@@ -2705,37 +2691,53 @@ resolve_mixers (struct loop *loop, tree chrec)
 tree
 number_of_latch_executions (struct loop *loop)
 {
-  tree res, type;
   edge exit;
   struct tree_niter_desc niter_desc;
+  tree may_be_zero;
+  tree res;
 
-  /* Determine whether the number_of_iterations_in_loop has already
+  /* Determine whether the number of iterations in loop has already
      been computed.  */
   res = loop->nb_iterations;
   if (res)
     return res;
-  res = chrec_dont_know;
+
+  may_be_zero = NULL_TREE;
 
   if (dump_file && (dump_flags & TDF_DETAILS))
-    fprintf (dump_file, "(number_of_iterations_in_loop\n");
+    fprintf (dump_file, "(number_of_iterations_in_loop = \n");
 
+  res = chrec_dont_know;
   exit = single_exit (loop);
-  if (!exit)
-    goto end;
 
-  if (!number_of_iterations_exit (loop, exit, &niter_desc, false))
-    goto end;
+  if (exit && number_of_iterations_exit (loop, exit, &niter_desc, false))
+    {
+      may_be_zero = niter_desc.may_be_zero;
+      res = niter_desc.niter;
+    }
+
+  if (res == chrec_dont_know
+      || !may_be_zero
+      || integer_zerop (may_be_zero))
+    ;
+  else if (integer_nonzerop (may_be_zero))
+    res = build_int_cst (TREE_TYPE (res), 0);
 
-  type = TREE_TYPE (niter_desc.niter);
-  if (integer_nonzerop (niter_desc.may_be_zero))
-    res = build_int_cst (type, 0);
-  else if (integer_zerop (niter_desc.may_be_zero))
-    res = niter_desc.niter;
+  else if (COMPARISON_CLASS_P (may_be_zero))
+    res = fold_build3 (COND_EXPR, TREE_TYPE (res), may_be_zero,
+                      build_int_cst (TREE_TYPE (res), 0), res);
   else
     res = chrec_dont_know;
 
-end:
-  return set_nb_iterations_in_loop (loop, res);
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fprintf (dump_file, "  (set_nb_iterations_in_loop = ");
+      print_generic_expr (dump_file, res, 0);
+      fprintf (dump_file, "))\n");
+    }
+
+  loop->nb_iterations = res;
+  return res;
 }
 
 /* Returns the number of executions of the exit condition of LOOP,

diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c
index 9592832f9b7259463e8538a60b99032ef19ba476..bda640f3e0eafb11b834b423d38cc006a80cfb9d 100644 (file)
--- a/gcc/tree-ssa-loop-ivopts.c
+++ b/gcc/tree-ssa-loop-ivopts.c
@@ -681,6 +681,11 @@ contains_abnormal_ssa_name_p (tree expr)
                            idx_contains_abnormal_ssa_name_p,
                            NULL);
 
+  if (code == COND_EXPR)
+    return contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 0))
+      || contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 1))
+      || contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 2));
+
   switch (codeclass)
     {
     case tcc_binary: