diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 4513d40cda5..054ee524c7a 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -3162,6 +3162,21 @@ cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t,
   if (r == NULL_TREE)
     r = fold_binary_loc (loc, code, type, lhs, rhs);
 
+  if (r == NULL_TREE
+      && (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
+      && TREE_CODE (lhs) == INTEGER_CST
+      && TREE_CODE (rhs) == INTEGER_CST
+      && wi::neg_p (wi::to_wide (rhs)))
+    {
+      /* For diagnostics and -fpermissive emulate previous behavior of
+	 handling shifts by negative amount.  */
+      tree nrhs = const_unop (NEGATE_EXPR, TREE_TYPE (rhs), rhs);
+      if (nrhs)
+	r = fold_binary_loc (loc,
+			     code == LSHIFT_EXPR ? RSHIFT_EXPR : LSHIFT_EXPR,
+			     type, lhs, nrhs);
+    }
+
   if (r == NULL_TREE)
     {
       if (lhs == orig_lhs && rhs == orig_rhs)
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index c2cf1a94f94..632a241a964 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -992,26 +992,19 @@ wide_int_binop (wide_int &res,
       res = wi::bit_and (arg1, arg2);
       break;
 
-    case RSHIFT_EXPR:
     case LSHIFT_EXPR:
       if (wi::neg_p (arg2))
-	{
-	  tmp = -arg2;
-	  if (code == RSHIFT_EXPR)
-	    code = LSHIFT_EXPR;
-	  else
-	    code = RSHIFT_EXPR;
-	}
-      else
-        tmp = arg2;
+	return false;
+      res = wi::lshift (arg1, arg2);
+      break;
 
-      if (code == RSHIFT_EXPR)
-	/* It's unclear from the C standard whether shifts can overflow.
-	   The following code ignores overflow; perhaps a C standard
-	   interpretation ruling is needed.  */
-	res = wi::rshift (arg1, tmp, sign);
-      else
-	res = wi::lshift (arg1, tmp);
+    case RSHIFT_EXPR:
+      if (wi::neg_p (arg2))
+	return false;
+      /* It's unclear from the C standard whether shifts can overflow.
+	 The following code ignores overflow; perhaps a C standard
+	 interpretation ruling is needed.  */
+      res = wi::rshift (arg1, arg2, sign);
       break;
 
     case RROTATE_EXPR:
diff --git a/gcc/match.pd b/gcc/match.pd
index cbb4bf0b32d..4d290ad3c25 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2900,8 +2900,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 /* Optimize -1 >> x for arithmetic right shifts.  */
 (simplify
  (rshift integer_all_onesp@0 @1)
- (if (!TYPE_UNSIGNED (type)
-      && tree_expr_nonnegative_p (@1))
+ (if (!TYPE_UNSIGNED (type))
   @0))
 
 /* Optimize (x >> c) << c into x & (-1<<c).  */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr96929.c b/gcc/testsuite/gcc.dg/tree-ssa/pr96929.c
new file mode 100644
index 00000000000..65b6147f7a4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr96929.c
@@ -0,0 +1,21 @@
+/* PR tree-optimization/96929 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump "baz \\\(\\\);" "optimized" } } */
+/* { dg-final { scan-tree-dump-times "return -1;" 2 "optimized" } } */
+/* { dg-final { scan-tree-dump-not " >> " "optimized" } } */
+
+int baz (void);
+
+int
+foo (void)
+{
+  return -1 >> baz ();
+}
+
+int
+bar (int y)
+{
+  int z = -1;
+  return z >> y;
+}
diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c
index 9a2ff6227b4..466be20f155 100644
--- a/gcc/tree-ssa-ccp.c
+++ b/gcc/tree-ssa-ccp.c
@@ -1432,13 +1432,7 @@ bit_value_binop (enum tree_code code, signop sgn, int width,
 	  else
 	    {
 	      if (wi::neg_p (shift))
-		{
-		  shift = -shift;
-		  if (code == RSHIFT_EXPR)
-		    code = LSHIFT_EXPR;
-		  else
-		    code = RSHIFT_EXPR;
-		}
+		break;
 	      if (code == RSHIFT_EXPR)
 		{
 		  *mask = wi::rshift (wi::ext (r1mask, width, sgn), shift, sgn);