[llvm-dev] how to make "test-suite" pass even if the current compiler configuration has FP contraction enabled

[Abe Skolnik via llvm-dev]

Dear all,

To my knowledge, there are two ways to proceed to make "test-suite" newly-able to pass even 
when the current compiler configuration has FP contraction enabled:

   #1: Test for FP contraction at run-time,
       disable tests accordingly.

       https://reviews.llvm.org/D25635


   #2: Assume that FP contraction might be in effect,
       require the "test-suite" user to specify that it isn`t when
       it isn`t and the user wants the additional tests to be done.

       https://reviews.llvm.org/D25749



The main advantages of strategy #1:

   * it should be much more reliable than a user-specified flag

   * it should enable more tests to be active when FP contraction
     is _not_ in effect with less [no] user intervention


The main disadvantage of strategy #1 is that it seems likely to be difficult to implement, 
given the way the CMake+Lit system works, and given the fact that cross-building the tests is 
supported.




The main advantages of strategy #2:

   * easy to implement

   * already implemented and tested for the CMake+Lit system

   * initial implementation for the old Makefile-based system exists [although not yet tested]


The main disadvantage of strategy #2 is that user intervention will be required in order to 
activate the sensitive tests that are disabled by default.


Feedback is welcome.

Regards,

Abe