Fix range checking for trunc conversions, f64.convert_u_i32, and add tests.

Author: sunfishcode

ml-proto/src/spec/f32_convert.ml

@@ -8,6 +8,10 @@ let demote_f64 x =
 let convert_s_i32 x =
   make_nan_nondeterministic (F32.of_float (Int32.to_float x))
 
+(*
+ * Similar to convert_u_i64 below, the high half of the i32 range are beyond
+ * the range where f32 can represent odd numbers.
+ *)
 let convert_u_i32 x =
   make_nan_nondeterministic
     (F32.of_float (if x >= Int32.zero then
@@ -18,6 +22,12 @@ let convert_u_i32 x =
 let convert_s_i64 x =
   make_nan_nondeterministic (F32.of_float (Int64.to_float x))
 
+(*
+ * Values in the low half of the int64 range can be converted with a signed
+ * conversion. The high half is beyond the range where f32 can represent odd
+ * numbers, so we can shift the value right, do a conversion, and then scale it
+ * back up, without worrying about losing the least-significant digit.
+ *)
 let convert_u_i64 x =
   make_nan_nondeterministic
     (F32.of_float (if x >= Int64.zero then

ml-proto/src/spec/f64_convert.ml

@@ -8,16 +8,25 @@ let promote_f32 x =
 let convert_s_i32 x =
   make_nan_nondeterministic (F64.of_float (Int32.to_float x))
 
+(*
+ * Unlike the other convert_u functions, the high half of the i32 range is
+ * within the range where f32 can represent odd numbers, so we can't do the
+ * shift. Instead, we can use int64 signed arithmetic.
+ *)
 let convert_u_i32 x =
   make_nan_nondeterministic
-    (F64.of_float (if x >= Int32.zero then
-       Int32.to_float x
-     else
-       Int32.to_float (Int32.shift_right_logical x 1) *. 2.))
+    (F64.of_float
+       (Int64.to_float (Int64.logand (Int64.of_int32 x) 0x00000000ffffffffL)))
 
 let convert_s_i64 x =
   make_nan_nondeterministic (F64.of_float (Int64.to_float x))
 
+(*
+ * Values in the low half of the int64 range can be converted with a signed
+ * conversion. The high half is beyond the range where f64 can represent odd
+ * numbers, so we can shift the value right, do a conversion, and then scale it
+ * back up, without worrying about losing the least-significant digit.
+ *)
 let convert_u_i64 x =
   make_nan_nondeterministic
     (F64.of_float (if x >= Int64.zero then

ml-proto/src/spec/i32_convert.ml

@@ -6,8 +6,8 @@ let trunc_s_f32 x =
   if F32.ne x x then
     raise Numerics.InvalidConversionToInteger
   else let xf = F32.to_float x in
-    if xf >= (Int32.to_float Int32.max_int) +. 1. ||
-       xf <= (Int32.to_float Int32.min_int) -. 1. then
+    if xf >= -.(Int32.to_float Int32.min_int) ||
+       xf < (Int32.to_float Int32.min_int) then
       raise Numerics.IntegerOverflow
     else
       Int32.of_float xf
@@ -16,8 +16,8 @@ let trunc_u_f32 x =
   if F32.ne x x then
     raise Numerics.InvalidConversionToInteger
   else let xf = F32.to_float x in
-      if xf >= (Int32.to_float Int32.max_int) *. 2. +. 2. ||
-         xf <= -1. then
+    if xf >= -.(Int32.to_float Int32.min_int) *. 2. ||
+       xf <= -1. then
       raise Numerics.IntegerOverflow
     else
       Int64.to_int32 (Int64.of_float xf)
@@ -26,8 +26,8 @@ let trunc_s_f64 x =
   if F64.ne x x then
     raise Numerics.InvalidConversionToInteger
   else let xf = F64.to_float x in
-      if xf >= (Int32.to_float Int32.max_int) +. 1. ||
-         xf <= (Int32.to_float Int32.min_int) -. 1. then
+    if xf >= -.(Int32.to_float Int32.min_int) ||
+       xf < (Int32.to_float Int32.min_int) then
       raise Numerics.IntegerOverflow
     else
       Int32.of_float xf
@@ -36,8 +36,8 @@ let trunc_u_f64 x =
   if F64.ne x x then
     raise Numerics.InvalidConversionToInteger
   else let xf = F64.to_float x in
-      if xf >= (Int32.to_float Int32.max_int) *. 2. +. 2. ||
-         xf <= -1. then
+    if xf >= -.(Int32.to_float Int32.min_int) *. 2. ||
+       xf <= -1. then
       raise Numerics.IntegerOverflow
     else
       Int64.to_int32 (Int64.of_float xf)

ml-proto/src/spec/i64_convert.ml

@@ -8,8 +8,8 @@ let trunc_s_f32 x =
   if F32.ne x x then
     raise Numerics.InvalidConversionToInteger
   else let xf = F32.to_float x in
-    if xf >= (Int64.to_float Int64.max_int) +. 1. ||
-       xf <= (Int64.to_float Int64.min_int) -. 1. then
+    if xf >= -.(Int64.to_float Int64.min_int) ||
+       xf < (Int64.to_float Int64.min_int) then
       raise Numerics.IntegerOverflow
     else
       Int64.of_float xf
@@ -18,10 +18,10 @@ let trunc_u_f32 x =
   if F32.ne x x then
     raise Numerics.InvalidConversionToInteger
   else let xf = F32.to_float x in
-      if xf >= (Int64.to_float Int64.max_int) *. 2. +. 2. ||
-         xf <= -1. then
+    if xf >= -.(Int64.to_float Int64.min_int) *. 2. ||
+       xf <= -1. then
       raise Numerics.IntegerOverflow
-    else if xf >= (Int64.to_float Int64.max_int) +. 1. then
+    else if xf >= -.(Int64.to_float Int64.min_int) then
       Int64.logxor (Int64.of_float (xf -. 9223372036854775808.)) Int64.min_int
     else
       Int64.of_float xf
@@ -30,8 +30,8 @@ let trunc_s_f64 x =
   if F64.ne x x then
     raise Numerics.InvalidConversionToInteger
   else let xf = F64.to_float x in
-      if xf >= (Int64.to_float Int64.max_int) +. 1. ||
-         xf <= (Int64.to_float Int64.min_int) -. 1. then
+    if xf >= -.(Int64.to_float Int64.min_int) ||
+       xf < (Int64.to_float Int64.min_int) then
       raise Numerics.IntegerOverflow
     else
       Int64.of_float xf
@@ -40,10 +40,10 @@ let trunc_u_f64 x =
   if F64.ne x x then
     raise Numerics.InvalidConversionToInteger
   else let xf = F64.to_float x in
-      if xf >= (Int64.to_float Int64.max_int) *. 2. +. 2. ||
-         xf <= -1. then
+    if xf >= -.(Int64.to_float Int64.min_int) *. 2. ||
+       xf <= -1. then
       raise Numerics.IntegerOverflow
-    else if xf >= (Int64.to_float Int64.max_int) +. 1. then
+    else if xf >= -.(Int64.to_float Int64.min_int) then
       Int64.logxor (Int64.of_float (xf -. 9223372036854775808.)) Int64.min_int
     else
       Int64.of_float xf