[PATCH] D84932: [builtins] Add more test cases for __div[sdt]f3 LibCalls

[Anatoly Trosinenko via Phabricator via cfe-commits]

atrosinenko added inline comments.


================
Comment at: compiler-rt/test/builtins/Unit/divdf3_test.c:80
+    // divisor is 1.0 as UQ1.31
+    if (test__divdf3(0x1.0p+0, 0x1.00000001p+0, UINT64_C(0x3fefffffffe00000)))
       return 1;
----------------
sepavloff wrote:
> atrosinenko wrote:
> > sepavloff wrote:
> > > Is 0x1.00000001p+0 equal to 1.0 in UQ1.31?
> > Divisor is `1.(31 zeroes)1` after restoring the implicit bit, so it is **truncated** to 1.0 as UQ1.31. Instead of counting bits carefully, it would probably be better to add several tests with the `1` bit shifted 1-2 places left/right as well as if the divisor is round up instead of truncating - //just in case//. :) So, with table-driven test it would probably be simpler to not make extra assumptions on the implementation.
> > Divisor is 1.(31 zeroes)1
> 
> So it is **not** `1.0` and the comment is misleading. Try rewording the comment to avoid confusion. Maybe `divisor is truncated to 1.0 in UQ1.31` or something like that. 
Now got it, thank you.


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  https://reviews.llvm.org/D84932/new/

https://reviews.llvm.org/D84932