[PATCH] D46236: [Driver, CodeGen] rename options to disable an FP cast optimization

[Roman Lebedev via Phabricator via cfe-commits]

lebedev.ri accepted this revision.
lebedev.ri added a comment.
This revision is now accepted and ready to land.

Overall makes sense to me.



================
Comment at: docs/ReleaseNotes.rst:94
+  :option:`-fno-strict-float-cast-overflow` -
+   When a floating-point value is not representable in a casted-to integer
+   type, the code has undefined behavior according to the language standard.
----------------
```
- in a casted-to integer type
+ in destination integer type
```
?



================
Comment at: docs/ReleaseNotes.rst:96
+   type, the code has undefined behavior according to the language standard.
+   Clang will not guarantee any particular result in that event. With the
+   'no-strict' option, Clang attempts to match the overflowing behavior of
----------------
s/event/case/ ?


================
Comment at: docs/UsersManual.rst:1260
 
-   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.
+   When a floating-point value is not representable in a casted-to integer 
+   type, the code has undefined behavior according to the language standard.
----------------
same


================
Comment at: docs/UsersManual.rst:1262
+   type, the code has undefined behavior according to the language standard.
+   Clang will not guarantee any particular result in that event. With the
+   'no-strict' option, Clang attempts to match the overflowing behavior of 
----------------
same


================
Comment at: include/clang/Driver/Options.td:1033
+def fstrict_float_cast_overflow : Flag<["-"],
+  "fstrict-float-cast-overflow">, Group<f_Group>, Flags<[CC1Option]>;
+def fno_strict_float_cast_overflow : Flag<["-"],
----------------
Maybe add `HelpText<"">` to both of them, just to explain what they are,
specify that the first is the default, and the second relaxes language rules to help broken code.


================
Comment at: test/CodeGen/no-junk-ftrunc.c:7
 
 // RUN: %clang_cc1 -S %s -emit-llvm -o - | FileCheck %s --check-prefix=DEFAULT
 // DEFAULT-LABEL: main
----------------
It wouldn't hurt to duplicate this run-line, and explicitly pass `-fno-strict-float-cast-overflow`.


https://reviews.llvm.org/D46236