[GR-38588] Fix Float#/ when dividing by Rational

PullRequest: truffleruby/3337

Author: bjfish

CHANGELOG.md

@@ -24,6 +24,7 @@ Compatibility:
 * Implement `rb_gc_mark_maybe` and `rb_global_variable` to ensure `VALUE` stay live in C extensions (@aardvark179).
 * Implement `rb_imemo_tmpbuf` allocation for `ripper` (@aardvark179).
 * Implement `inherit` argument for `Module#class_variables` (#2653, @bjfish).
+* Fix `Float#/` when dividing by `Rational` (@bjfish).
 
 Performance:
 

spec/ruby/core/float/divide_spec.rb

@@ -36,4 +36,8 @@
     -> { 13.0 / "10"    }.should raise_error(TypeError)
     -> { 13.0 / :symbol }.should raise_error(TypeError)
   end
+
+  it "divides correctly by Rational numbers" do
+    (1.2345678901234567 / Rational(1, 10000000000000000000)).should == 1.2345678901234567e+19
+  end
 end

spec/ruby/core/integer/fdiv_spec.rb

@@ -55,6 +55,11 @@
     num.fdiv(den).should == -0.5555555555555556
   end
 
+  it "rounds to the correct float for bignum denominators" do
+    1.fdiv(10**324).should == 0.0
+    1.fdiv(10**323).should == 1.0e-323
+  end
+
   it "performs floating-point division between self and a Float" do
     8.fdiv(9.0).should be_close(0.888888888888889, TOLERANCE)
   end

src/main/java/org/truffleruby/core/numeric/IntegerNodes.java

@@ -286,7 +286,7 @@ protected Object mul(Object a, Object b,
 
     }
 
-    @Primitive(name = "interger_fdiv")
+    @Primitive(name = "integer_fdiv")
     public abstract static class FDivNode extends PrimitiveArrayArgumentsNode {
 
         @Specialization
@@ -302,19 +302,19 @@ protected double fDivLongLong(long num, long den) {
         @TruffleBoundary
         @Specialization
         protected double fDivLongBig(long num, RubyBignum den) {
-            return new BigDecimal(num).divide(new BigDecimal(den.value), 17, RoundingMode.HALF_UP).doubleValue();
+            return new BigDecimal(num).divide(new BigDecimal(den.value), 323, RoundingMode.HALF_UP).doubleValue();
         }
 
         @TruffleBoundary
         @Specialization
         protected double fDivBigLong(RubyBignum num, long den) {
-            return new BigDecimal(num.value).divide(new BigDecimal(den), 17, RoundingMode.HALF_UP).doubleValue();
+            return new BigDecimal(num.value).divide(new BigDecimal(den), 323, RoundingMode.HALF_UP).doubleValue();
         }
 
         @TruffleBoundary
         @Specialization
         protected double fDivBigBig(RubyBignum num, RubyBignum den) {
-            return new BigDecimal(num.value).divide(new BigDecimal(den.value), 17, RoundingMode.HALF_UP).doubleValue();
+            return new BigDecimal(num.value).divide(new BigDecimal(den.value), 323, RoundingMode.HALF_UP).doubleValue();
         }
 
     }

src/main/ruby/truffleruby/core/integer.rb

@@ -111,7 +111,7 @@ def divmod(b)
 
   def fdiv(n)
     if Primitive.object_kind_of?(n, Integer)
-      Primitive.interger_fdiv(self, n)
+      Primitive.integer_fdiv(self, n)
     else
       redo_coerced :fdiv, n
     end