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[COMMITTED,GCC13] PR tree-optimization/110315 - Reduce the initial size of int_range_max.

Message ID 1a8e843d-3289-3319-1dd1-53e790ba60d9@redhat.com
State New
Headers show
Series [COMMITTED,GCC13] PR tree-optimization/110315 - Reduce the initial size of int_range_max. | expand

Commit Message

Andrew MacLeod Sept. 26, 2023, 6:06 p.m. UTC
This patch adds the ability to resize ranges as needed, defaulting to no 
resizing.  int_range_max now defaults to 3 sub-ranges (instead of 255) 
and grows to 255 when the range being calculated does not fit.

Bootstraps on x86_64-pc-linux-gnu with no regressions.   Pushed.

Andrew
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Patch

From 70639014a69cf50fe11dc1adbfe1db4c7760ce69 Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacleod@redhat.com>
Date: Tue, 26 Sep 2023 09:44:39 -0400
Subject: [PATCH] Reduce the initial size of int_range_max.

This patch adds the ability to resize ranges as needed, defaulting to no
resizing.  int_range_max now defaults to 3 sub-ranges (instead of 255)
and grows to 255 when the range being calculated does not fit.

	PR tree-optimization/110315
	* value-range-storage.h (vrange_allocator::alloc_irange): Adjust
	new params.
	* value-range.cc (irange::operator=): Resize range.
	(irange::irange_union): Same.
	(irange::irange_intersect): Same.
	(irange::invert): Same.
	* value-range.h (irange::maybe_resize): New.
	(~int_range): New.
	(int_range_max): Default to 3 sub-ranges and resize as needed.
	(int_range::int_range): Adjust for resizing.
	(int_range::operator=): Same.
---
 gcc/value-range-storage.h |  2 +-
 gcc/value-range.cc        | 15 ++++++
 gcc/value-range.h         | 96 +++++++++++++++++++++++++++------------
 3 files changed, 83 insertions(+), 30 deletions(-)

diff --git a/gcc/value-range-storage.h b/gcc/value-range-storage.h
index 6da377ebd2e..1ed6f1ccd61 100644
--- a/gcc/value-range-storage.h
+++ b/gcc/value-range-storage.h
@@ -184,7 +184,7 @@  vrange_allocator::alloc_irange (unsigned num_pairs)
   // Allocate the irange and required memory for the vector.
   void *r = alloc (sizeof (irange));
   tree *mem = static_cast <tree *> (alloc (nbytes));
-  return new (r) irange (mem, num_pairs);
+  return new (r) irange (mem, num_pairs, /*resizable=*/false);
 }
 
 inline frange *
diff --git a/gcc/value-range.cc b/gcc/value-range.cc
index ec826c2fe1b..753f5e8cc76 100644
--- a/gcc/value-range.cc
+++ b/gcc/value-range.cc
@@ -831,6 +831,10 @@  irange::operator= (const irange &src)
       copy_to_legacy (src);
       return *this;
     }
+
+  int needed = src.num_pairs ();
+  maybe_resize (needed);
+
   if (src.legacy_mode_p ())
     {
       copy_legacy_to_multi_range (src);
@@ -2506,6 +2510,7 @@  irange::irange_union (const irange &r)
   // Now it simply needs to be copied, and if there are too many
   // ranges, merge some.  We wont do any analysis as to what the
   // "best" merges are, simply combine the final ranges into one.
+  maybe_resize (i / 2);
   if (i > m_max_ranges * 2)
     {
       res[m_max_ranges * 2 - 1] = res[i - 1];
@@ -2605,6 +2610,11 @@  irange::irange_intersect (const irange &r)
   if (r.irange_contains_p (*this))
     return intersect_nonzero_bits (r);
 
+  // ?? We could probably come up with something smarter than the
+  // worst case scenario here.
+  int needed = num_pairs () + r.num_pairs ();
+  maybe_resize (needed);
+
   signop sign = TYPE_SIGN (TREE_TYPE(m_base[0]));
   unsigned bld_pair = 0;
   unsigned bld_lim = m_max_ranges;
@@ -2831,6 +2841,11 @@  irange::invert ()
       m_num_ranges = 1;
       return;
     }
+
+  // At this point, we need one extra sub-range to represent the
+  // inverse.
+  maybe_resize (m_num_ranges + 1);
+
   // The algorithm is as follows.  To calculate INVERT ([a,b][c,d]), we
   // generate [-MIN, a-1][b+1, c-1][d+1, MAX].
   //
diff --git a/gcc/value-range.h b/gcc/value-range.h
index 969b2b68418..96e59ecfa72 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -172,7 +172,8 @@  public:
   bool legacy_verbose_intersect (const irange *);	// DEPRECATED
 
 protected:
-  irange (tree *, unsigned);
+  void maybe_resize (int needed);
+  irange (tree *, unsigned nranges, bool resizable);
   // potential promotion to public?
   tree tree_lower_bound (unsigned = 0) const;
   tree tree_upper_bound (unsigned) const;
@@ -200,6 +201,8 @@  protected:
   void copy_to_legacy (const irange &);
   void copy_legacy_to_multi_range (const irange &);
 
+  // Hard limit on max ranges allowed.
+  static const int HARD_MAX_RANGES = 255;
 private:
   friend void gt_ggc_mx (irange *);
   friend void gt_pch_nx (irange *);
@@ -214,15 +217,21 @@  private:
 
   bool intersect (const wide_int& lb, const wide_int& ub);
   unsigned char m_num_ranges;
+  bool m_resizable;
   unsigned char m_max_ranges;
   tree m_nonzero_mask;
+protected:
   tree *m_base;
 };
 
 // Here we describe an irange with N pairs of ranges.  The storage for
 // the pairs is embedded in the class as an array.
+//
+// If RESIZABLE is true, the storage will be resized on the heap when
+// the number of ranges needed goes past N up to a max of
+// HARD_MAX_RANGES.  This new storage is freed upon destruction.
 
-template<unsigned N>
+template<unsigned N, bool RESIZABLE = false>
 class GTY((user)) int_range : public irange
 {
 public:
@@ -233,7 +242,7 @@  public:
   int_range (tree type);
   int_range (const int_range &);
   int_range (const irange &);
-  virtual ~int_range () = default;
+  virtual ~int_range ();
   int_range& operator= (const int_range &);
 private:
   template <unsigned X> friend void gt_ggc_mx (int_range<X> *);
@@ -472,6 +481,38 @@  is_a <frange> (vrange &v)
   return v.m_discriminator == VR_FRANGE;
 }
 
+// For resizable ranges, resize the range up to HARD_MAX_RANGES if the
+// NEEDED pairs is greater than the current capacity of the range.
+
+inline void
+irange::maybe_resize (int needed)
+{
+  if (!m_resizable || m_max_ranges == HARD_MAX_RANGES)
+    return;
+
+  if (needed > m_max_ranges)
+    {
+      m_max_ranges = HARD_MAX_RANGES;
+      tree *newmem = new tree[m_max_ranges * 2];
+      memcpy (newmem, m_base, sizeof (tree) * num_pairs () * 2);
+      m_base = newmem;
+    }
+}
+
+template<unsigned N, bool RESIZABLE>
+inline
+int_range<N, RESIZABLE>::~int_range ()
+{
+  if (RESIZABLE && m_base != m_ranges)
+    delete m_base;
+}
+
+// This is an "infinite" precision irange for use in temporary
+// calculations.  It starts with a sensible default covering 99% of
+// uses, and goes up to HARD_MAX_RANGES when needed.  Any allocated
+// storage is freed upon destruction.
+typedef int_range<3, /*RESIZABLE=*/true> int_range_max;
+
 class vrange_visitor
 {
 public:
@@ -490,10 +531,6 @@  public:
 // There are copy operators to seamlessly copy to/fro multi-ranges.
 typedef int_range<1> value_range;
 
-// This is an "infinite" precision irange for use in temporary
-// calculations.
-typedef int_range<255> int_range_max;
-
 // This is an "infinite" precision range object for use in temporary
 // calculations for any of the handled types.  The object can be
 // transparently used as a vrange.
@@ -872,64 +909,65 @@  gt_pch_nx (int_range<N> *x, gt_pointer_operator op, void *cookie)
 // Constructors for irange
 
 inline
-irange::irange (tree *base, unsigned nranges)
+irange::irange (tree *base, unsigned nranges, bool resizable)
 {
   m_discriminator = VR_IRANGE;
   m_base = base;
   m_max_ranges = nranges;
+  m_resizable = resizable;
   set_undefined ();
 }
 
 // Constructors for int_range<>.
 
-template<unsigned N>
+template<unsigned N, bool RESIZABLE>
 inline
-int_range<N>::int_range ()
-  : irange (m_ranges, N)
+int_range<N, RESIZABLE>::int_range ()
+  : irange (m_ranges, N, RESIZABLE)
 {
 }
 
-template<unsigned N>
-int_range<N>::int_range (const int_range &other)
-  : irange (m_ranges, N)
+template<unsigned N, bool RESIZABLE>
+int_range<N, RESIZABLE>::int_range (const int_range &other)
+  : irange (m_ranges, N, RESIZABLE)
 {
   irange::operator= (other);
 }
 
-template<unsigned N>
-int_range<N>::int_range (tree min, tree max, value_range_kind kind)
-  : irange (m_ranges, N)
+template<unsigned N, bool RESIZABLE>
+int_range<N, RESIZABLE>::int_range (tree min, tree max, value_range_kind kind)
+  : irange (m_ranges, N, RESIZABLE)
 {
   irange::set (min, max, kind);
 }
 
-template<unsigned N>
-int_range<N>::int_range (tree type)
-  : irange (m_ranges, N)
+template<unsigned N, bool RESIZABLE>
+int_range<N, RESIZABLE>::int_range (tree type)
+  : irange (m_ranges, N, RESIZABLE)
 {
   set_varying (type);
 }
 
-template<unsigned N>
-int_range<N>::int_range (tree type, const wide_int &wmin, const wide_int &wmax,
+template<unsigned N, bool RESIZABLE>
+int_range<N, RESIZABLE>::int_range (tree type, const wide_int &wmin, const wide_int &wmax,
 			 value_range_kind kind)
-  : irange (m_ranges, N)
+  : irange (m_ranges, N, RESIZABLE)
 {
   tree min = wide_int_to_tree (type, wmin);
   tree max = wide_int_to_tree (type, wmax);
   set (min, max, kind);
 }
 
-template<unsigned N>
-int_range<N>::int_range (const irange &other)
-  : irange (m_ranges, N)
+template<unsigned N, bool RESIZABLE>
+int_range<N, RESIZABLE>::int_range (const irange &other)
+  : irange (m_ranges, N, RESIZABLE)
 {
   irange::operator= (other);
 }
 
-template<unsigned N>
-int_range<N>&
-int_range<N>::operator= (const int_range &src)
+template<unsigned N, bool RESIZABLE>
+int_range<N, RESIZABLE>&
+int_range<N, RESIZABLE>::operator= (const int_range &src)
 {
   irange::operator= (src);
   return *this;
-- 
2.41.0