simonbyrne created this revision.
This is probably good to document, as the behaviour of `-fstrict-aliasing`
differs from gcc in a quite important way (see
https://bugs.llvm.org//show_bug.cgi?id=31928) .
https://reviews.llvm.org/D30538
Files:
docs/UsersManual.rst
Index: docs/UsersManual.rst
===================================================================
--- docs/UsersManual.rst
+++ docs/UsersManual.rst
@@ -1098,6 +1098,14 @@
the behavior of sanitizers in the ``cfi`` group to allow checking
of cross-DSO virtual and indirect calls.
+.. option:: -f[no-]strict-aliasing
+
+ Enables/disables the strict aliasing assumption, which assumes that
+ objects of different types do not share the same location in memory.
+
+ NOTE: unlike gcc, clang does not allow "type-punning" by writing and
+ reading from different union members without `-fno-strict-aliasing`
+ enabled.
.. option:: -fstrict-vtable-pointers
Index: docs/UsersManual.rst
===================================================================
--- docs/UsersManual.rst
+++ docs/UsersManual.rst
@@ -1098,6 +1098,14 @@
the behavior of sanitizers in the ``cfi`` group to allow checking
of cross-DSO virtual and indirect calls.
+.. option:: -f[no-]strict-aliasing
+
+ Enables/disables the strict aliasing assumption, which assumes that
+ objects of different types do not share the same location in memory.
+
+ NOTE: unlike gcc, clang does not allow "type-punning" by writing and
+ reading from different union members without `-fno-strict-aliasing`
+ enabled.
.. option:: -fstrict-vtable-pointers
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