Slightly optimize Math.mod (AssemblyScript#1521)

Author: MaxGraey

std/assembly/math.ts

@@ -1583,19 +1583,18 @@ export namespace NativeMath {
  }
  var ux1 = ux << 1;
  if (ux1 <= uy1) {
- if (ux1 == uy1) return 0 * x;
- return x;
+ return x * f64(ux1 != uy1);
  }
  if (!ex) {
  ex -= builtin_clz<i64>(ux << 12);
- ux <<= -ex + 1;
+ ux <<= 1 - ex;
  } else {
  ux &= <u64>-1 >> 12;
  ux |= 1 << 52;
  }
  if (!ey) {
  ey -= builtin_clz<i64>(uy << 12);
- uy <<= -ey + 1;
+ uy <<= 1 - ey;
  } else {
  uy &= <u64>-1 >> 12;
  uy |= 1 << 52;
@@ -1622,8 +1621,7 @@ export namespace NativeMath {
  } else {
  ux >>= -ex + 1;
  }
- ux |= sx << 63;
- return reinterpret<f64>(ux);
+ return reinterpret<f64>(ux | (sx << 63));
  }
 
  export function rem(x: f64, y: f64): f64 { // see: musl/src/math/remquo.c
@@ -1640,14 +1638,14 @@ export namespace NativeMath {
  var uxi = ux;
  if (!ex) {
  ex -= builtin_clz<i64>(uxi << 12);
- uxi <<= -ex + 1;
+ uxi <<= 1 - ex;
  } else {
  uxi &= <u64>-1 >> 12;
  uxi |= 1 << 52;
  }
  if (!ey) {
  ey -= builtin_clz<i64>(uy << 12);
- uy <<= -ey + 1;
+ uy <<= 1 - ey;
  } else {
  uy &= <u64>-1 >> 12;
  uy |= 1 << 52;
@@ -2884,27 +2882,26 @@ export namespace NativeMathf {
  var uy = reinterpret<u32>(y);
  var ex = <i32>(ux >> 23 & 0xFF);
  var ey = <i32>(uy >> 23 & 0xFF);
- var sx = ux & 0x80000000;
+ var sm = ux & 0x80000000;
  var uy1 = uy << 1;
  if (uy1 == 0 || ex == 0xFF || isNaN<f32>(y)) {
  let m = x * y;
  return m / m;
  }
  var ux1 = ux << 1;
  if (ux1 <= uy1) {
- if (ux1 == uy1) return 0 * x;
- return x;
+ return x * f32(ux1 != uy1);
  }
  if (!ex) {
  ex -= builtin_clz<u32>(ux << 9);
- ux <<= -ex + 1;
+ ux <<= 1 - ex;
  } else {
  ux &= <u32>-1 >> 9;
  ux |= 1 << 23;
  }
  if (!ey) {
  ey -= builtin_clz<u32>(uy << 9);
- uy <<= -ey + 1;
+ uy <<= 1 - ey;
  } else {
  uy &= <u32>-1 >> 9;
  uy |= 1 << 23;
@@ -2931,8 +2928,7 @@ export namespace NativeMathf {
  } else {
  ux >>= -ex + 1;
  }
- ux |= sx;
- return reinterpret<f32>(ux);
+ return reinterpret<f32>(ux | sm);
  }
 
  export function rem(x: f32, y: f32): f32 { // see: musl/src/math/remquof.c
@@ -2946,14 +2942,14 @@ export namespace NativeMathf {
  if (ux << 1 == 0) return x;
  if (!ex) {
  ex -= builtin_clz<u32>(uxi << 9);
- uxi <<= -ex + 1;
+ uxi <<= 1 - ex;
  } else {
  uxi &= <u32>-1 >> 9;
  uxi |= 1 << 23;
  }
  if (!ey) {
  ey -= builtin_clz<u32>(uy << 9);
- uy <<= -ey + 1;
+ uy <<= 1 - ey;
  } else {
  uy &= <u32>-1 >> 9;
  uy |= 1 << 23;

tests/compiler/binary.untouched.wat

@@ -1288,16 +1288,12 @@
  local.get $7
  i32.le_u
  if
+ local.get $0
  local.get $9
  local.get $7
- i32.eq
- if
- f32.const 0
- local.get $0
- f32.mul
- return
- end
- local.get $0
+ i32.ne
+ f32.convert_i32_u
+ f32.mul
  return
  end
  local.get $4
@@ -1311,11 +1307,9 @@
  i32.sub
  local.set $4
  local.get $2
- i32.const 0
+ i32.const 1
  local.get $4
  i32.sub
- i32.const 1
- i32.add
  i32.shl
  local.set $2
  else
@@ -1343,11 +1337,9 @@
  i32.sub
  local.set $5
  local.get $3
- i32.const 0
+ i32.const 1
  local.get $5
  i32.sub
- i32.const 1
- i32.add
  i32.shl
  local.set $3
  else
@@ -1460,8 +1452,6 @@
  local.get $2
  local.get $6
  i32.or
- local.set $2
- local.get $2
  f32.reinterpret_i32
  )
  (func $~lib/math/NativeMathf.pow (param $0 f32) (param $1 f32) (result f32)
@@ -2163,16 +2153,12 @@
  local.get $7
  i64.le_u
  if
+ local.get $0
  local.get $9
  local.get $7
- i64.eq
- if
- f64.const 0
- local.get $0
- f64.mul
- return
- end
- local.get $0
+ i64.ne
+ f64.convert_i32_u
+ f64.mul
  return
  end
  local.get $4
@@ -2188,11 +2174,9 @@
  i64.sub
  local.set $4
  local.get $2
- i64.const 0
+ i64.const 1
  local.get $4
  i64.sub
- i64.const 1
- i64.add
  i64.shl
  local.set $2
  else
@@ -2222,11 +2206,9 @@
  i64.sub
  local.set $5
  local.get $3
- i64.const 0
+ i64.const 1
  local.get $5
  i64.sub
- i64.const 1
- i64.add
  i64.shl
  local.set $3
  else
@@ -2341,8 +2323,6 @@
  i64.const 63
  i64.shl
  i64.or
- local.set $2
- local.get $2
  f64.reinterpret_i64
  )
  (func $start:binary