Implemented loose checking for potential widened loads

docs/ASAN.rst

Index: docs/ASAN.rst
diff --git a/docs/ASAN.rst b/docs/ASAN.rst
index 5526c59b2458b6134c762c58f3a4b46722270e00..d815817c042656f9f56fb4df35bb1a1629ea4872 100644
--- a/docs/ASAN.rst
+++ b/docs/ASAN.rst
@@ -27,3 +27,12 @@ AddressSanitizer and properly linked into a final executable using
 subzero/pydir/szbuild.py with the --fsanitize-address flag, i.e.::
 
     pydir/szbuild.py --fsanitize-address hello.pexe
+
+Handling Wide Loads
+===================
+
+Since AddressSanitizer is implemented only in Subzero, the target .pexe may
+contain widened loads that would cause false positives. To avoid reporting such
+loads as errors, we treat any word-aligned, four byte load as a potentially
+widened load and only check the first byte of the loaded word against shadow
+memory.