1 files changed, 41 insertions, 0 deletions
diff --git a/tests/runner.py b/tests/runner.py
index 5af33b72..630dd75c 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -1138,6 +1138,47 @@ m_divisor is 1091269979
       '''
       self.do_run(src, '3217489085')
 
+    def test_i32_mul_semiprecise(self):
+      src = r'''
+        #include <stdio.h>
+
+        typedef unsigned int uint;
+
+        // from cube2, zlib licensed
+
+        #define N (624)             
+        #define M (397)                
+        #define K (0x9908B0DFU)       
+
+        static uint state[N];
+        static int next = N;
+
+        void seedMT(uint seed)
+        {
+            state[0] = seed;
+            for(uint i = 1; i < N; i++) // if we do not do this precisely, at least we should coerce to int immediately, not wait
+                state[i] = seed = 1812433253U * (seed ^ (seed >> 30)) + i;
+            next = 0;
+        }
+
+        int main() {
+          seedMT(5497);
+          for (int i = 0; i < 10; i++) printf("%d: %u\n", i, state[i]);
+          return 0;
+        }
+      '''
+      self.do_run(src, '''0: 5497
+1: 2916432318
+2: 2502517762
+3: 3151524867
+4: 2323729668
+5: 2053478917
+6: 2409490438
+7: 848473607
+8: 691103752
+9: 3915535113
+''')
+
     def test_i16_emcc_intrinsic(self):
       Settings.CORRECT_SIGNS = 1 # Relevant to this test