[Arith] Allow const folding on fp16 involving one and zero (#13631)

apache · Dec 16, 2022 · cded048 · cded048
1 parent 0eabbac
commit cded048
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Showing 2 changed files with 18 additions and 19 deletions.
diff --git a/src/arith/const_fold.h b/src/arith/const_fold.h
@@ -142,8 +142,6 @@ inline Optional<PrimExpr> TryConstFold<tir::Add>(PrimExpr a, PrimExpr b) {
                                                        static_cast<float>(fb->value)));
       } else if (rtype.bits() == 64) {
         return FloatImm(rtype, fa->value + fb->value);
-      } else {
-        return NullOpt;
       }
     }
     if (fa && fa->value == 0) return b;
@@ -171,8 +169,6 @@ inline Optional<PrimExpr> TryConstFold<tir::Sub>(PrimExpr a, PrimExpr b) {
                                                        static_cast<float>(fb->value)));
       } else if (rtype.bits() == 64) {
         return FloatImm(rtype, fa->value - fb->value);
-      } else {
-        return NullOpt;
       }
     }
     if (fb && fb->value == 0) return a;
@@ -202,8 +198,6 @@ inline Optional<PrimExpr> TryConstFold<tir::Mul>(PrimExpr a, PrimExpr b) {
                                                        static_cast<float>(fb->value)));
       } else if (rtype.bits() == 64) {
         return FloatImm(rtype, fa->value * fb->value);
-      } else {
-        return NullOpt;
       }
     }
     if (fa) {
@@ -243,8 +237,6 @@ inline Optional<PrimExpr> TryConstFold<tir::Div>(PrimExpr a, PrimExpr b) {
                                                        static_cast<float>(fb->value)));
       } else if (rtype.bits() == 64) {
         return FloatImm(rtype, fa->value / fb->value);
-      } else {
-        return NullOpt;
       }
     }
     if (fa && fa->value == 0) return a;

diff --git a/tests/python/unittest/test_arith_canonical_simplify.py b/tests/python/unittest/test_arith_canonical_simplify.py
@@ -15,6 +15,7 @@
 # specific language governing permissions and limitations
 # under the License.
 import tvm
+import tvm.testing
 from tvm import te
 
 
@@ -124,6 +125,22 @@ def test_div_simplify():
     ck.verify(fld(17 + 47 * x, 16), fld(x * 47 + 17, 16))
 
 
+def test_fp16_const_fold():
+    ck = CanonicalChecker()
+    zero = tvm.tir.const(0, "float16")
+    one = tvm.tir.const(1, "float16")
+    half = tvm.tir.const(0.5, "float16")
+
+    ck.verify(zero + half, half)
+    ck.verify(half - zero, half)
+
+    ck.verify(zero * half, zero)
+    ck.verify(half * one, half)
+
+    ck.verify(half / one, half)
+    ck.verify(zero / half, zero)
+
+
 def test_floormod_simplify():
     ck = CanonicalChecker()
     flm = tvm.te.floormod
@@ -356,14 +373,4 @@ def test_simplify_cast():
 
 
 if __name__ == "__main__":
-    test_floormod_simplify()
-    test_mul_sum_simplify()
-    test_simplify_if_then_else()
-    test_div_simplify()
-    test_reduce_simplify()
-    test_reduce_combiner_simplify()
-
-    test_split_index_simplify()
-    test_canonical_mixed()
-    test_complex_cases()
-    test_simplify_cast()
+    tvm.testing.main()