diff --git a/gcc/testsuite/gcc.dg/pr110984-1.c b/gcc/testsuite/gcc.dg/pr110984-1.c
new file mode 100644
index 00000000000..85b19eb8279
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr110984-1.c
@@ -0,0 +1,37 @@
+/* PR tree-optimization/110984 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -g0 -ffast-math -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-times "\[ij]_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=) \[ij]_\[0-9]+\\(D\\)" 14 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "i_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=) 5\\.0" 14 "optimized" } } */
+
+/* This is similar to pr94589-2.c except use signed char as the type for the [-1,2] case */
+
+#define A __attribute__((noipa))
+A int f1 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c == 0; }
+A int f2 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c != 0; }
+A int f3 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c > 0; }
+A int f4 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c < 0; }
+A int f5 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c >= 0; }
+A int f6 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c <= 0; }
+A int f7 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c == -1; }
+A int f8 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c != -1; }
+A int f9 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c > -1; }
+A int f10 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c <= -1; }
+A int f11 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c == 1; }
+A int f12 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c != 1; }
+A int f13 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c < 1; }
+A int f14 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c >= 1; }
+A int f15 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c == 0; }
+A int f16 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c != 0; }
+A int f17 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c > 0; }
+A int f18 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c < 0; }
+A int f19 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c >= 0; }
+A int f20 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c <= 0; }
+A int f21 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c == -1; }
+A int f22 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c != -1; }
+A int f23 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c > -1; }
+A int f24 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c <= -1; }
+A int f25 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c == 1; }
+A int f26 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c != 1; }
+A int f27 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c < 1; }
+A int f28 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c >= 1; }
diff --git a/gcc/testsuite/gcc.dg/pr110984-2.c b/gcc/testsuite/gcc.dg/pr110984-2.c
new file mode 100644
index 00000000000..cddce045745
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr110984-2.c
@@ -0,0 +1,21 @@
+/* PR tree-optimization/110984 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -g0 -ffast-math -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-times "\[ij]_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=) \[ij]_\[0-9]+\\(D\\)" 6 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "i_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=) 5\\.0" 6 "optimized" } } */
+
+/* This is similar to pr94589-2.c except use signed char and use unsigned types to check against the variable, which means removing the non !=/== comparisons.  */
+
+#define A __attribute__((noipa))
+A int f1 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t == 0; }
+A int f2 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t != 0; }
+A int f7 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t == -1; }
+A int f8 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t != -1; }
+A int f11 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t == 1; }
+A int f12 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t != 1; }
+A int f15 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t == 0; }
+A int f16 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t != 0; }
+A int f21 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t == -1; }
+A int f22 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t != -1; }
+A int f25 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t == 1; }
+A int f26 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t != 1; }
diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index 485662dfcc7..5f24d62c49a 100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -2346,7 +2346,8 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
     }
   if (lhs != (orig_use_lhs ? orig_use_lhs : phires)
       || !tree_fits_shwi_p (rhs)
-      || !IN_RANGE (tree_to_shwi (rhs), -1, 1))
+      || !(IN_RANGE (tree_to_shwi (rhs), 0, 1)
+	   || integer_all_onesp (rhs)))
     return false;
 
   if (is_cast)
@@ -2356,9 +2357,20 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
       /* As for -ffast-math we assume the 2 return to be
 	 impossible, canonicalize (unsigned) res <= 1U or
 	 (unsigned) res < 2U into res >= 0 and (unsigned) res > 1U
-	 or (unsigned) res >= 2U as res < 0.  */
+	 or (unsigned) res >= 2U as res < 0.
+	 Sometimes we get (unsigned)res != N.  Support those cases too. */
       switch (cmp)
 	{
+	case NE_EXPR:
+	case EQ_EXPR:
+	  {
+	    tree newrhs = fold_convert (TREE_TYPE (phires), rhs);
+	    tree tmp = fold_convert (TREE_TYPE (rhs), newrhs);
+	    if (!tree_int_cst_equal (rhs, tmp))
+	      return false;
+	    rhs = newrhs;
+	    break;
+	  }
 	case LE_EXPR:
 	  if (!integer_onep (rhs))
 	    return false;
@@ -2382,7 +2394,8 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
 	default:
 	  return false;
 	}
-      rhs = build_zero_cst (TREE_TYPE (phires));
+      if (cmp != EQ_EXPR && cmp != NE_EXPR)
+	rhs = build_zero_cst (TREE_TYPE (phires));
     }
   else if (orig_use_lhs)
     {
