[PATCH] D68257: [Support] Add mathematical constants

[Evandro Menezes via Phabricator via llvm-commits]

evandro marked 3 inline comments as done.
evandro added inline comments.


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Comment at: llvm/include/llvm/Support/MathExtras.h:66
+                 inv_sqrtpi = 0.5641895835477563, // https://oeis.org/A087197
+                 sqrt2      = 1.414213562373095, // https://oeis.org/A002193
+                 inv_sqrt2  = 0.7071067811865475,
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efriedma wrote:
> The correct value of sqrt(2) in double-precision is 1.4142135623730951.
> 
> And now I don't trust any of the other values...
`double` has a precision of 15 or 16 significant digits.  I don't understand why are you suggesting 17 significant digits when you asked to trim the precision down.

Besides, the reference I provided states that this value is 1.41421356237309505.  Whether it's rounded to 1.4142135623730950 or 1.4142135623730951 is a bit moot, IMO.


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Comment at: llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp:1944
+      // FIXME: The `long double` type is not fully supported by the classes
+      // `APFloat` and `Constant`.
+      Eul = ConstantFP::get(Log->getType(), numbers::e);
----------------
efriedma wrote:
> I'm not sure this describes the issue correctly.  You can specify a long double as a string, or raw bits.  It can't interoperate with the native long double because that might have the wrong width.
What wording would you suggest, please?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D68257/new/

https://reviews.llvm.org/D68257