[Bug tree-optimization/97467] [11 Regression] ICE in verify_range, at value-range.cc:369 (-Os and above) since r11-3685-gfcae5121154d1c33

[aldyh at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97467

--- Comment #2 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
Ranger can figure out that the RHS operand of a shift is a zero and feeds it to
operator_lshift::op1_range, which then uses it to create a swapped [1,0] range.

Testing the following patch:

diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index 0efa00186e8..30d2a4d3987 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -1579,6 +1579,11 @@ operator_lshift::op1_range (irange &r,
       wide_int shift = wi::to_wide (shift_amount);
       if (wi::lt_p (shift, 0, SIGNED))
        return false;
+      if (shift == 0)
+       {
+         r = lhs;
+         return true;
+       }

       // Work completely in unsigned mode to start.
       tree utype = type;