[PATCH] tree-optimization/108819 - niter analysis ICE with unexpected constant

[Richard Biener via Gcc-patches]

The following makes sure we do not ICE on unfolded stmts like
_1 = 1 & 1.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

        PR tree-optimization/108819
        * tree-ssa-loop-niter.cc (number_of_iterations_cltz): Check
        we have an SSA name as iv_2 as expected.

        * gcc.dg/pr108819.c: New testcase.
---
 gcc/testsuite/gcc.dg/pr108819.c | 14 ++++++++++++++
 gcc/tree-ssa-loop-niter.cc      |  6 ++++--
 2 files changed, 18 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr108819.c

diff --git a/gcc/testsuite/gcc.dg/pr108819.c b/gcc/testsuite/gcc.dg/pr108819.c
new file mode 100644
index 00000000000..a651f819908
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr108819.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fno-tree-ccp -fno-tree-forwprop" } */
+
+int a, b;
+int main() {
+  int d = 1;
+  for (; b; b++)
+    if (a < 1)
+      while (d <= a && a <= 0UL) {
+        int *e = &d;
+        *e = 0;
+      }
+  return 0;
+}
diff --git a/gcc/tree-ssa-loop-niter.cc b/gcc/tree-ssa-loop-niter.cc
index 581bf5d067b..1ce5e736ce3 100644
--- a/gcc/tree-ssa-loop-niter.cc
+++ b/gcc/tree-ssa-loop-niter.cc
@@ -2354,7 +2354,8 @@ number_of_iterations_cltz (loop_p loop, edge exit,
       gimple *and_stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond_stmt));
       if (!is_gimple_assign (and_stmt)
          || gimple_assign_rhs_code (and_stmt) != BIT_AND_EXPR
-         || !integer_pow2p (gimple_assign_rhs2 (and_stmt)))
+         || !integer_pow2p (gimple_assign_rhs2 (and_stmt))
+         || TREE_CODE (gimple_assign_rhs1 (and_stmt)) != SSA_NAME)
        return false;
 
       checked_bit = tree_log2 (gimple_assign_rhs2 (and_stmt));
@@ -2382,7 +2383,8 @@ number_of_iterations_cltz (loop_p loop, edge exit,
             precision.  */
          iv_2 = gimple_assign_rhs1 (test_value_stmt);
          tree rhs_type = TREE_TYPE (iv_2);
-         if (TREE_CODE (rhs_type) != INTEGER_TYPE
+         if (TREE_CODE (iv_2) != SSA_NAME
+             || TREE_CODE (rhs_type) != INTEGER_TYPE
              || (TYPE_PRECISION (rhs_type)
                  != TYPE_PRECISION (test_value_type)))
            return false;
-- 
2.35.3