[PATCH] D68257: [Support] Add mathematical constants

[Eli Friedman via Phabricator via llvm-commits]

efriedma requested changes to this revision.
efriedma added inline comments.
This revision now requires changes to proceed.


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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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The correct value of sqrt(2) in double-precision is 1.4142135623730951.

And now I don't trust any of the other values...


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Comment at: llvm/include/llvm/Support/MathExtras.h:71
+                 phi        = 1.618033988749895; // https://oeis.org/A001622
+constexpr float ef          = 2.718282, // https://oeis.org/A001113
+                egammaf     = 0.5772157, // https://oeis.org/A001620
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Please mark the constants with "f", e.g. `2.718282f`, so there isn't an extra rounding step.


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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);
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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.


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

https://reviews.llvm.org/D68257