zext sign correction for bitcasting from <32 bits to i64

diclophis · Apr 19, 2012 · a00c765 · a00c765
1 parent 8cbede3
commit a00c765
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diff --git a/src/analyzer.js b/src/analyzer.js
@@ -544,6 +544,10 @@ function analyzer(data, sidePass) {
                       params: [(signed && j + whole > sourceElements.length) ? signedKeepAlive : null],
                       type: 'i32',
                     };
+                    if (j == 0 && isUnsignedOp(value.op) && sourceBits < 32) {
+                      // zext sign correction
+                      result.ident = makeSignOp(result.ident, 'i' + sourceBits, 'un', 1, 1);
+                    }
                     if (fraction != 0) {
                       var other = {
                         intertype: 'value',

diff --git a/tests/runner.py b/tests/runner.py
@@ -909,6 +909,27 @@ def test_i64_precise(self):
         code = open(os.path.join(self.get_dir(), 'src.cpp.o.js')).read()
         assert 'goog.math.Long' not in code and 'jsbn' not in code, 'i64 precise math should not have been included if not actually used'
 
+    def test_i64_zextneg(self):
+      if Settings.USE_TYPED_ARRAYS != 2: return self.skip('full i64 stuff only in ta2')
+
+      src = r'''
+        #include <stdint.h>
+        #include <stdio.h>
+
+        int main(int argc, char *argv[])
+        {
+            uint8_t byte = 0x80;
+            uint16_t two = byte;
+            uint32_t four = byte;
+            uint64_t eight = byte;
+
+            printf("value: %d,%d,%d,%lld.\n", byte, two, four, eight);
+
+            return 0;
+        }
+      '''
+      self.do_run(src, 'value: 128,128,128,128.')
+
     def test_cube2hash(self):
       # A good test of i64 math
       if Settings.USE_TYPED_ARRAYS != 2: return self.skip('requires ta2 C-style memory aliasing')