diff --git a/docs/ispc.rst b/docs/ispc.rst
index a5ada9d9..5d26c93a 100644
--- a/docs/ispc.rst
+++ b/docs/ispc.rst
@@ -3147,7 +3147,7 @@ library.  State for the RNG is maintained in an instance of the
 ::
 
     struct RNGState;
-    void seed_rng(varying RNGState * uniform state, uniform int seed)
+    void seed_rng(varying RNGState * uniform state, int seed)
     void seed_rng(uniform RNGState * uniform state, uniform int seed)
 
 After the RNG is seeded, the ``random()`` function can be used to get a
diff --git a/examples/aobench/ao.ispc b/examples/aobench/ao.ispc
index 692dc367..e768c8c7 100644
--- a/examples/aobench/ao.ispc
+++ b/examples/aobench/ao.ispc
@@ -210,7 +210,7 @@ static void ao_scanlines(uniform int y0, uniform int y1, uniform int w,
         { { 1.0f, 0.0f, -2.2f }, 0.5f } };
     RNGState rngstate;
 
-    seed_rng(&rngstate, y0);
+    seed_rng(&rngstate, programIndex + (y0 << (programIndex & 15)));
     float invSamples = 1.f / nsubsamples;
 
     foreach_tiled(y = y0 ... y1, x = 0 ... w, 
diff --git a/examples/aobench_instrumented/ao.ispc b/examples/aobench_instrumented/ao.ispc
index 06d9b505..4fd9bedb 100644
--- a/examples/aobench_instrumented/ao.ispc
+++ b/examples/aobench_instrumented/ao.ispc
@@ -211,7 +211,7 @@ static void ao_scanlines(uniform int y0, uniform int y1, uniform int w,
         { { 1.0f, 0.0f, -2.2f }, 0.5f } };
     RNGState rngstate;
 
-    seed_rng(&rngstate, y0);
+    seed_rng(&rngstate, programIndex + (y0 << (programIndex & 15)));
 
     // Compute the mapping between the 'programCount'-wide program
     // instances running in parallel and samples in the image.  
diff --git a/stdlib.ispc b/stdlib.ispc
index 4cfcdea4..ea4c6b98 100644
--- a/stdlib.ispc
+++ b/stdlib.ispc
@@ -4026,60 +4026,13 @@ static inline uniform float frandom(uniform RNGState * uniform state)
     return floatbits(0x3F800000 | irand)-1.0f;
 }
 
-static inline uniform unsigned int __seed4(varying RNGState * uniform state, 
-                                           uniform int start,
-                                           uniform unsigned int seed) {
-    uniform unsigned int c1 = 0xf0f0f0f0;
-    uniform unsigned int c2 = 0x0f0f0f0f;
-
-    state->z1 = insert(state->z1, start + 0, seed);
-    state->z1 = insert(state->z1, start + 1, seed ^ c1);
-    state->z1 = insert(state->z1, start + 2, (seed << 3) ^ c1);
-    state->z1 = insert(state->z1, start + 3, (seed << 2) ^ c2);
-
-    seed += 131;
-    state->z2 = insert(state->z2, start + 0, seed);
-    state->z2 = insert(state->z2, start + 1, seed ^ c1);
-    state->z2 = insert(state->z2, start + 2, (seed << 3) ^ c1);
-    state->z2 = insert(state->z2, start + 3, (seed << 2) ^ c2);
-
-    seed ^= extract(state->z2, 2);
-    state->z3 = insert(state->z3, start + 0, seed);
-    state->z3 = insert(state->z3, start + 1, seed ^ c1);
-    state->z3 = insert(state->z3, start + 2, (seed << 3) ^ c1);
-    state->z3 = insert(state->z3, start + 3, (seed << 2) ^ c2);
-
-    seed <<= 4;
-    seed += 3;
-    seed ^= extract(state->z1, 3);
-    state->z4 = insert(state->z4, start + 0, seed);
-    state->z4 = insert(state->z4, start + 1, seed ^ c1);
-    state->z4 = insert(state->z4, start + 2, (seed << 3) ^ c1);
-    state->z4 = insert(state->z4, start + 3, (seed << 2) ^ c2);
-
-    return seed;
-}
-
 static inline void seed_rng(varying RNGState * uniform state, 
-                            uniform unsigned int seed) {
-    if (programCount == 1) {
-        state->z1 = seed;
-        state->z2 = seed ^ 0xbeeff00d;
-        state->z3 = ((seed & 0xffff) << 16) | (seed >> 16);
-        state->z4 = (((seed & 0xff) << 24) | ((seed & 0xff00)  << 8) |
-                     ((seed & 0xff0000) >> 8) | (seed & 0xff000000) >> 24);
-    }
-    else {
-        seed = __seed4(state, 0, seed);
-        if (programCount == 8)
-            __seed4(state, 4, seed ^ 0xbeeff00d);
-        if (programCount == 16) {
-            __seed4(state, 4,  seed ^ 0xbeeff00d);
-            __seed4(state, 8,  ((seed & 0xffff) << 16) | (seed >> 16));
-            __seed4(state, 12, (((seed & 0xff) << 24) | ((seed & 0xff00)  << 8) |
-                                ((seed & 0xff0000) >> 8) | (seed & 0xff000000) >> 24));
-        }
-    }
+                            unsigned int seed) {
+    state->z1 = seed;
+    state->z2 = seed ^ 0xbeeff00d;
+    state->z3 = ((seed & 0xffff) << 16) | (seed >> 16);
+    state->z4 = (((seed & 0xff) << 24) | ((seed & 0xff00)  << 8) |
+                 ((seed & 0xff0000) >> 8) | (seed & 0xff000000) >> 24);
 }
 
 static inline void seed_rng(uniform RNGState * uniform state, 
diff --git a/tests/rand-distrib-1.ispc b/tests/rand-distrib-1.ispc
index a53cef12..3a23a917 100644
--- a/tests/rand-distrib-1.ispc
+++ b/tests/rand-distrib-1.ispc
@@ -3,7 +3,7 @@ export uniform int width() { return programCount; }
 
 export void f_fu(uniform float RET[], uniform float aFOO[], uniform float b) {
     RNGState state;
-    seed_rng(&state, 1);
+    seed_rng(&state, programIndex);
     int count[32];
     for (uniform int i = 0; i < 32; ++i)
         count[i] = (b == 5.) ? 0 : 1;
diff --git a/tests/rand-distrib.ispc b/tests/rand-distrib.ispc
index edf24f2b..393ec063 100644
--- a/tests/rand-distrib.ispc
+++ b/tests/rand-distrib.ispc
@@ -3,7 +3,7 @@ export uniform int width() { return programCount; }
 
 export void f_f(uniform float RET[], uniform float aFOO[]) {
     RNGState state;
-    seed_rng(&state, 1);
+    seed_rng(&state, programIndex);
     float sum = 0;
     uniform int iters = 40000;
     for (unsigned int i = 0; i < iters; ++i)