(math) avoid zero seed inside seedRandom (#2053)

Author: MaxGraey

std/assembly/math.ts

@@ -1413,15 +1413,15 @@ export namespace NativeMath {
   }
 
   export function seedRandom(value: i64): void {
-    random_seeded = true;
+    // Instead zero seed use golden ratio:
+    // phi = (1 + sqrt(5)) / 2
+    // trunc(2^64 / phi) = 0x9e3779b97f4a7c15
+    if (value == 0) value = 0x9e3779b97f4a7c15;
     random_state0_64 = murmurHash3(value);
     random_state1_64 = murmurHash3(~random_state0_64);
     random_state0_32 = splitMix32(<u32>value);
     random_state1_32 = splitMix32(random_state0_32);
-    assert(
-      random_state0_64 != 0 && random_state1_64 != 0 &&
-      random_state0_32 != 0 && random_state1_32 != 0
-    );
+    random_seeded = true;
   }
 
   export function random(): f64 { // see: v8/src/base/utils/random-number-generator.cc

tests/compiler/std/array.optimized.wat

@@ -65,11 +65,11 @@
  (global $~lib/math/res128_hi (mut i64) (i64.const 0))
  (global $~lib/math/rempio2f_y (mut f64) (f64.const 0))
  (global $~lib/util/math/log_tail (mut f64) (f64.const 0))
- (global $~lib/math/random_seeded (mut i32) (i32.const 0))
  (global $~lib/math/random_state0_64 (mut i64) (i64.const 0))
  (global $~lib/math/random_state1_64 (mut i64) (i64.const 0))
  (global $~lib/math/random_state0_32 (mut i32) (i32.const 0))
  (global $~lib/math/random_state1_32 (mut i32) (i32.const 0))
+ (global $~lib/math/random_seeded (mut i32) (i32.const 0))
  (global $~lib/math/NativeMath.sincos_sin (mut f64) (f64.const 0))
  (global $~lib/math/NativeMath.sincos_cos (mut f64) (f64.const 0))
  (memory $0 1)
@@ -214,8 +214,6 @@
  (data (i32.const 14289) "\a08\07\ae\"\d5?Y\c7d\81p\be.=\00\00\00\00\00\e0\e6?")
  (data (i32.const 14321) "\d0\c8S\f7{\d5?\ef@]\ee\ed\ad\1f=\00\00\00\00\00\c0\e6?")
  (data (i32.const 14353) "`Y\df\bd\d5\d5?\dce\a4\08*\0b\n\bd")
- (data (i32.const 14380) ",")
- (data (i32.const 14392) "\01\00\00\00\18\00\00\00~\00l\00i\00b\00/\00m\00a\00t\00h\00.\00t\00s")
  (export "memory" (memory $0))
  (start $~start)
  (func $~lib/math/NativeMath.scalbn (param $0 f64) (param $1 i32) (result f64)
@@ -8527,11 +8525,12 @@
  (func $~lib/math/NativeMath.seedRandom (param $0 i64)
   (local $1 i32)
   (local $2 i64)
-  (local $3 i64)
-  (local $4 i32)
-  i32.const 1
-  global.set $~lib/math/random_seeded
+  i64.const -7046029254386353131
+  local.get $0
   local.get $0
+  i64.eqz
+  select
+  local.tee $0
   i64.const 33
   i64.shr_u
   local.get $0
@@ -8552,7 +8551,6 @@
   i64.xor
   global.set $~lib/math/random_state0_64
   global.get $~lib/math/random_state0_64
-  local.tee $3
   i64.const -1
   i64.xor
   local.tee $2
@@ -8608,7 +8606,6 @@
   i32.xor
   global.set $~lib/math/random_state0_32
   global.get $~lib/math/random_state0_32
-  local.tee $4
   i32.const 1831565813
   i32.add
   local.tee $1
@@ -8639,31 +8636,8 @@
   local.get $1
   i32.xor
   global.set $~lib/math/random_state1_32
-  global.get $~lib/math/random_state1_32
-  i32.const 0
-  i32.ne
-  i32.const 0
-  local.get $4
-  i32.const 0
-  global.get $~lib/math/random_state1_64
-  i64.const 0
-  i64.ne
-  i32.const 0
-  local.get $3
-  i64.const 0
-  i64.ne
-  select
-  select
-  select
-  i32.eqz
-  if
-   i32.const 0
-   i32.const 14400
-   i32.const 1421
-   i32.const 5
-   call $~lib/builtins/abort
-   unreachable
-  end
+  i32.const 1
+  global.set $~lib/math/random_seeded
  )
  (func $std/math/test_round (param $0 f64) (param $1 f64) (result i32)
   (local $2 f64)