[gcc r13-8121] gimple-range-cache: Fix ICEs when dumping details [PR111967]

[Jakub Jelinek]

https://gcc.gnu.org/g:80bf483565a11a34239be47012d0b6990dec6690

commit r13-8121-g80bf483565a11a34239be47012d0b6990dec6690
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Nov 13 08:47:41 2023 +0100

    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.
    
    (cherry picked from commit 5a0c302d2d721b9650c1e354695dbba87364c334)

Diff:
---
 gcc/gimple-range-cache.cc                | 16 +++++++++++-----
 gcc/testsuite/gcc.dg/tree-ssa/pr111967.c | 15 +++++++++++++++
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/gcc/gimple-range-cache.cc b/gcc/gimple-range-cache.cc
index e4e75943632..08327fc70ba 100644
--- a/gcc/gimple-range-cache.cc
+++ b/gcc/gimple-range-cache.cc
@@ -343,7 +343,7 @@ 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])
     {
@@ -410,7 +410,7 @@ 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])
 	{
@@ -432,11 +432,14 @@ 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 ())
 	    {
@@ -453,13 +456,16 @@ 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
index 00000000000..bbef390228a
--- /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);
+}