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From: "aldyh at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/97467] [11 Regression] ICE in verify_range, at value-range.cc:369 (-Os and above) since r11-3685-gfcae5121154d1c33
Date: Mon, 19 Oct 2020 08:06:09 +0000	[thread overview]
Message-ID: <bug-97467-4-6QLrtR763T@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-97467-4@http.gcc.gnu.org/bugzilla/>

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;

  parent reply	other threads:[~2020-10-19  8:06 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-17  7:47 [Bug tree-optimization/97467] New: ICE in verify_range, at value-range.cc:369 (-Os and above) su at cs dot ucdavis.edu
2020-10-19  7:20 ` [Bug tree-optimization/97467] ICE in verify_range, at value-range.cc:369 (-Os and above) since r11-3685-gfcae5121154d1c33 marxin at gcc dot gnu.org
2020-10-19  8:06 ` aldyh at gcc dot gnu.org [this message]
2020-10-19  9:37 ` [Bug tree-optimization/97467] [11 Regression] " cvs-commit at gcc dot gnu.org
2020-10-19  9:40 ` aldyh at gcc dot gnu.org

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