PRECISE_I32_MUL option for full precision in 32-bit multiply

1 files changed, 17 insertions, 0 deletions

diff --git a/tests/runner.py b/tests/runner.py
index 876990d2..32776167 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -953,6 +953,23 @@ m_divisor is 1091269979
       '''
       self.do_run(src, 'zero 2, 104', ['hallo'])
 
+    def test_i32_mul_precise(self):
+      if self.emcc_args == None: return self.skip('needs ta2')
+
+      self.emcc_args += ['-s', 'PRECISE_I32_MUL=1']
+      src = r'''
+        #include <stdio.h>
+
+        int main(int argc, char **argv) {
+          unsigned long d1 = 0x847c9b5d;
+          unsigned long q =  0x549530e1;
+          if (argc > 1000) { q += argc; d1 -= argc; } // confuse optimizer
+          printf("%lu\n", d1*q);
+          return 0;
+        }
+      '''
+      self.do_run(src, '3217489085')
+
     def test_i16_emcc_intrinsic(self):
       Settings.CORRECT_SIGNS = 1 # Relevant to this test