From 858476981f21a5e8b19789d8158b7653e3bba404 Mon Sep 17 00:00:00 2001 From: Justin Lebar Date: Sat, 21 Jan 2017 00:59:40 +0000 Subject: [PATCH] [ValueTracking] Clarify comments on CannotBeOrderedLessThanZero and SignBitMustBeZero. Reviewers: hfinkel, efriedma, sanjoy Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D28926 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292691 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Analysis/ValueTracking.h | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/include/llvm/Analysis/ValueTracking.h b/include/llvm/Analysis/ValueTracking.h index aaf6f888e06..5121c8b0c17 100644 --- a/include/llvm/Analysis/ValueTracking.h +++ b/include/llvm/Analysis/ValueTracking.h @@ -167,13 +167,25 @@ template class ArrayRef; bool CannotBeNegativeZero(const Value *V, const TargetLibraryInfo *TLI, unsigned Depth = 0); - /// Return true if we can prove that the specified FP value is either a NaN or - /// never less than 0.0. - /// If \p IncludeNeg0 is false, -0.0 is considered less than 0.0. + /// Return true if we can prove that the specified FP value is either NaN or + /// never less than -0.0. + /// + /// NaN --> true + /// +0 --> true + /// -0 --> true + /// x > +0 --> true + /// x < -0 --> false + /// bool CannotBeOrderedLessThanZero(const Value *V, const TargetLibraryInfo *TLI); - /// \returns true if we can prove that the specified FP value has a 0 sign - /// bit. + /// Return true if we can prove that the specified FP value's sign bit is 0. + /// + /// NaN --> true/false (depending on the NaN's sign bit) + /// +0 --> true + /// -0 --> false + /// x > +0 --> true + /// x < -0 --> false + /// bool SignBitMustBeZero(const Value *V, const TargetLibraryInfo *TLI); /// If the specified value can be set by repeating the same byte in memory,