diff --git a/gcc/match.pd b/gcc/match.pd
index 758322da217f57470840c15933862264221fef2c..7f76925b6c6d44ab806f95067b326a9e3732acd2 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -865,6 +865,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
     { tree utype = unsigned_type_for (type); }
     (convert (rshift (lshift (convert:utype @0) @2) @3))))))
 
+/* Fold ((type)(a<0)) << SIGNBITOFA into ((type)a) & signbit. */
+(simplify
+ (lshift (convert (lt @0 integer_zerop@1)) INTEGER_CST@2)
+ (if (TYPE_SIGN (TREE_TYPE (@0)) == SIGNED
+      && wi::eq_p (wi::to_wide (@2), TYPE_PRECISION (TREE_TYPE (@0)) - 1))
+  (with { wide_int wone = wi::one (TYPE_PRECISION (type)); }
+   (bit_and (convert @0)
+            { wide_int_to_tree (type,
+				wi::lshift (wone, wi::to_wide (@2))); }))))
+
 /* Fold (-x >> C) into -(x > 0) where C = precision(type) - 1.  */
 (for cst (INTEGER_CST VECTOR_CST)
  (simplify
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr103218-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr103218-1.c
new file mode 100644
index 0000000000000000000000000000000000000000..f086f073b386650c8166a44ff878493e06f45ef2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr103218-1.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* PR tree-optimization/103218 */
+
+/* These first two are removed during forwprop1 */
+signed char f(signed char a)
+{
+  signed char t = a < 0;
+  int tt = (unsigned char)(t << 7);
+  return tt;
+}
+signed char f0(signed char a)
+{
+  unsigned char t = a < 0;
+  int tt = (unsigned char)(t << 7);
+  return tt;
+}
+
+/* This one is removed during phiopt. */
+signed char  f1(signed char a)
+{
+    if (a < 0)
+      return 1u<<7;
+    return 0;
+}
+
+/* These three examples should remove "a < 0" by optimized. */
+/* { dg-final { scan-tree-dump-times "< 0" 0 "optimized"} } */