From b45eabcf82da2360b4243c820cd32b706f671c1a Mon Sep 17 00:00:00 2001 From: Craig Topper Date: Wed, 26 Apr 2017 16:39:58 +0000 Subject: [ValueTracking] Introduce a KnownBits struct to wrap the two APInts for computeKnownBits This patch introduces a new KnownBits struct that wraps the two APInt used by computeKnownBits. This allows us to treat them as more of a unit. Initially I've just altered the signatures of computeKnownBits and InstCombine's simplifyDemandedBits to pass a KnownBits reference instead of two separate APInt references. I'll do similar to the SelectionDAG version of computeKnownBits/simplifyDemandedBits as a separate patch. I've added a constructor that allows initializing both APInts to the same bit width with a starting value of 0. This reduces the repeated pattern of initializing both APInts. Once place default constructed the APInts so I added a default constructor for those cases. Going forward I would like to add more methods that will work on the pairs. For example trunc, zext, and sext occur on both APInts together in several places. We should probably add a clear method that can be used to clear both pieces. Maybe a method to check for conflicting information. A method to return (Zero|One) so we don't write it out everywhere. Maybe a method for (Zero|One).isAllOnesValue() to determine if all bits are known. I'm sure there are many other methods we can come up with. Differential Revision: https://reviews.llvm.org/D32376 llvm-svn: 301432 --- llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'llvm/lib/Transforms/Vectorize') diff --git a/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp b/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp index b0324d087fb..97dcb40a1d7 100644 --- a/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp +++ b/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp @@ -30,6 +30,7 @@ #include "llvm/IR/Value.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" +#include "llvm/Support/KnownBits.h" #include "llvm/Support/raw_ostream.h" #include "llvm/Transforms/Utils/Local.h" #include "llvm/Transforms/Vectorize.h" @@ -343,10 +344,9 @@ bool Vectorizer::isConsecutiveAccess(Value *A, Value *B) { // If any bits are known to be zero other than the sign bit in OpA, we can // add 1 to it while guaranteeing no overflow of any sort. if (!Safe) { - APInt KnownZero(BitWidth, 0); - APInt KnownOne(BitWidth, 0); - computeKnownBits(OpA, KnownZero, KnownOne, DL, 0, nullptr, OpA, &DT); - if (KnownZero.countTrailingZeros() < (BitWidth - 1)) + KnownBits Known(BitWidth); + computeKnownBits(OpA, Known, DL, 0, nullptr, OpA, &DT); + if (Known.Zero.countTrailingZeros() < (BitWidth - 1)) Safe = true; } -- cgit v1.2.3