gimple-range-cache: Fix ICEs when dumping details [PR111967]

The following testcase ICEs when dumping details.
When m_ssa_ranges vector is created, it is safe_grow_cleared (num_ssa_names),
but when when some new SSA_NAME is added, we strangely grow it to
num_ssa_names + 1 instead and later on the 3 argument dump method
iterates from 1 to m_ssa_ranges.length () - 1 and uses ssa_name (x)
on each; but because set_bb_range grew it one too much, ssa_name
(m_ssa_ranges.length () - 1) might be after the end of the ssanames
vector and ICE.

The fix grows the vector consistently only to num_ssa_names,
doesn't waste time checking m_ssa_ranges[0] because there is no
ssa_names (0), it is always NULL, before using ssa_name (x) checks
if we'll need it at all (we check later if m_ssa_ranges[x] is non-NULL,
so we might check it earlier as well) and also in the last loop
iterates until m_ssa_ranges.length () rather than num_ssa_names, I don't
see a reason for the inconsistency and in theory some SSA_NAME could be
added without set_bb_range called for it and the vector could be shorter
than the ssanames vector.

To actually fix the ICE, either the first hunk or the last 2 hunks
would be enough, but I think it doesn't hurt to change all the spots.

2023-11-13  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/111967
	* gimple-range-cache.cc (block_range_cache::set_bb_range): Grow
	m_ssa_ranges to num_ssa_names rather than num_ssa_names + 1.
	(block_range_cache::dump): Iterate from 1 rather than 0.  Don't use
	ssa_name (x) unless m_ssa_ranges[x] is non-NULL.  Iterate to
	m_ssa_ranges.length () rather than num_ssa_names.

	* gcc.dg/tree-ssa/pr111967.c: New test.

diff --git a/gcc/gimple-range-cache.cc b/gcc/gimple-range-cache.cc
index 89c0845457d0161693af4ca6aad2e8510ef8cea5..001e12f294c0bcbab2897a5849fd00ef35dbedea 100644 (file)
--- a/gcc/gimple-range-cache.cc
+++ b/gcc/gimple-range-cache.cc
@@ -390,7 +390,7 @@ block_range_cache::set_bb_range (tree name, const_basic_block bb,
 {
   unsigned v = SSA_NAME_VERSION (name);
   if (v >= m_ssa_ranges.length ())
-    m_ssa_ranges.safe_grow_cleared (num_ssa_names + 1);
+    m_ssa_ranges.safe_grow_cleared (num_ssa_names);
 
   if (!m_ssa_ranges[v])
     {
@@ -465,7 +465,7 @@ void
 block_range_cache::dump (FILE *f)
 {
   unsigned x;
-  for (x = 0; x < m_ssa_ranges.length (); ++x)
+  for (x = 1; x < m_ssa_ranges.length (); ++x)
     {
       if (m_ssa_ranges[x])
        {
@@ -487,11 +487,14 @@ block_range_cache::dump (FILE *f, basic_block bb, bool print_varying)
   bool summarize_varying = false;
   for (x = 1; x < m_ssa_ranges.length (); ++x)
     {
+      if (!m_ssa_ranges[x])
+       continue;
+
       if (!gimple_range_ssa_p (ssa_name (x)))
        continue;
 
       Value_Range r (TREE_TYPE (ssa_name (x)));
-      if (m_ssa_ranges[x] && m_ssa_ranges[x]->get_bb_range (r, bb))
+      if (m_ssa_ranges[x]->get_bb_range (r, bb))
        {
          if (!print_varying && r.varying_p ())
            {
@@ -508,13 +511,16 @@ block_range_cache::dump (FILE *f, basic_block bb, bool print_varying)
   if (summarize_varying)
     {
       fprintf (f, "VARYING_P on entry : ");
-      for (x = 1; x < num_ssa_names; ++x)
+      for (x = 1; x < m_ssa_ranges.length (); ++x)
        {
+         if (!m_ssa_ranges[x])
+           continue;
+
          if (!gimple_range_ssa_p (ssa_name (x)))
            continue;
 
          Value_Range r (TREE_TYPE (ssa_name (x)));
-         if (m_ssa_ranges[x] && m_ssa_ranges[x]->get_bb_range (r, bb))
+         if (m_ssa_ranges[x]->get_bb_range (r, bb))
            {
              if (r.varying_p ())
                {

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr111967.c b/gcc/testsuite/gcc.dg/tree-ssa/pr111967.c
new file mode 100644 (file)
index 0000000..bbef390
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr111967.c
@@ -0,0 +1,15 @@
+/* PR tree-optimization/111967 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-tree-forwprop -fdump-tree-evrp-all" } */
+
+void bar (char *);
+int a;
+char *b;
+
+void
+foo (void)
+{
+  long c = a & 3;
+  if (c)
+    bar (b + c);
+}