From: Andrew MacLeod <amacleod@redhat.com>
Date: Fri, 16 Oct 2020 19:02:42 +0000 (-0400)
Subject: Don't assert on a negative shift.
X-Git-Tag: basepoints/gcc-12~4241
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4a135bd987e7bff6d3b94efa085e0c246348b486;p=thirdparty%2Fgcc.git

Don't assert on a negative shift.

Don't assert, simply Return false for negative shifts as we can't tell
anything about the operand.

	PR tree-optimization/97462
	gcc/
	* range-op.cc (operator_lshift::op1_range): Don't trap on negative
	shifts.
	gcc/testsuite/
	* gcc.dg/pr97462.c: New file.
---

diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index 6108de367ad5..de4cfe45a48d 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -1577,7 +1577,8 @@ operator_lshift::op1_range (irange &r,
   if (op2.singleton_p (&shift_amount))
     {
       wide_int shift = wi::to_wide (shift_amount);
-      gcc_checking_assert (wi::gt_p (shift, 0, SIGNED));
+      if (wi::lt_p (shift, 0, SIGNED))
+	return false;
 
       // Work completely in unsigned mode to start.
       tree utype = type;
diff --git a/gcc/testsuite/gcc.dg/pr97462.c b/gcc/testsuite/gcc.dg/pr97462.c
new file mode 100644
index 000000000000..52c0533c98e2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr97462.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -w" } */
+
+int a, b;
+
+void d ()
+{
+  a << ~0 && b;
+  b = a;
+}