[Driver, CodeGen] rename options to disable an FP cast optimization

As suggested in the post-commit thread for rL331056, we should match these 
clang options with the established vocabulary of the corresponding sanitizer
option. Also, the use of 'strict' is well-known for these kinds of knobs, 
and we can improve the descriptive text in the docs.

So this intends to match the logic of D46135 but only change the words.
Matching LLVM commit to match this spelling of the attribute to follow shortly.

Differential Revision: https://reviews.llvm.org/D46236

llvm-svn: 331209

1 files changed, 7 insertions, 9 deletions

diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index 7425d2ad974..729adfdd397 100644
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -1255,15 +1255,13 @@ are listed below.
    flushed-to-zero number is preserved in the sign of 0, denormals are
    flushed to positive zero, respectively.
 
-.. option:: -f[no-]fp-cast-overflow-workaround
-
-   Enable a workaround for code that casts floating-point values to 
-   integers and back to floating-point. If the floating-point value 
-   is not representable in the intermediate integer type, the code is
-   incorrect according to the language standard. This flag will attempt 
-   to generate code as if the result of an overflowing conversion matches
-   the overflowing behavior of a target's native float-to-int conversion
-   instructions.
+.. option:: -f[no-]strict-float-cast-overflow
+
+   When a floating-point value is not representable in a destination integer 
+   type, the code has undefined behavior according to the language standard.
+   By default, Clang will not guarantee any particular result in that case.
+   With the 'no-strict' option, Clang attempts to match the overflowing behavior
+   of the target's native float-to-int conversion instructions.
 
 .. option:: -fwhole-program-vtables