[PATCH] D143195: ValueTracking: Add start of computeKnownFPClass API
Joshua Cranmer via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 14 12:59:11 PST 2023
jcranmer-intel added inline comments.
================
Comment at: llvm/include/llvm/Analysis/ValueTracking.h:217-221
+ /// If the sign bit is definitively known to be 1.
+ bool SignBitKnownOne = false;
+
+ /// If the sign bit is definitively known to be 0.
+ bool SignBitKnownZero = false;
----------------
Would it make sense instead to have a `std::optional<bool> KnownSignBit` here?
================
Comment at: llvm/lib/Analysis/ValueTracking.cpp:4111-4113
+ // Cannot produce nan
+ Known.KnownFPClasses =
+ static_cast<FPClassTest>(Known.KnownFPClasses & ~fcNan & fcAllFlags);
----------------
This pattern is common enough that I think `KnownFPClass` should have a `ruleOut(FPClassTest)` method or something similar to implement this method.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D143195/new/
https://reviews.llvm.org/D143195
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