From f90583eadc77e70db370e0bc5c9e99d13ef56ad3 Mon Sep 17 00:00:00 2001 From: Nikolai Bozhenov Date: Wed, 28 Jun 2017 12:15:13 +0000 Subject: [PATCH] Revert r306528 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306536 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ValueTracking.cpp | 9 +++++++++ test/Transforms/BBVectorize/loop1.ll | 2 +- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 5e9f8cc8d1b..fd519e2ad5c 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -54,6 +54,12 @@ const unsigned MaxDepth = 6; static cl::opt DomConditionsMaxUses("dom-conditions-max-uses", cl::Hidden, cl::init(20)); +// This optimization is known to cause performance regressions is some cases, +// keep it under a temporary flag for now. +static cl::opt +DontImproveNonNegativePhiBits("dont-improve-non-negative-phi-bits", + cl::Hidden, cl::init(true)); + /// Returns the bitwidth of the given scalar or pointer type. For vector types, /// returns the element type's bitwidth. static unsigned getBitWidth(Type *Ty, const DataLayout &DL) { @@ -1292,6 +1298,9 @@ static void computeKnownBitsFromOperator(const Operator *I, KnownBits &Known, Known.Zero.setLowBits(std::min(Known2.countMinTrailingZeros(), Known3.countMinTrailingZeros())); + if (DontImproveNonNegativePhiBits) + break; + auto *OverflowOp = dyn_cast(LU); if (OverflowOp && OverflowOp->hasNoSignedWrap()) { // If initial value of recurrence is nonnegative, and we are adding diff --git a/test/Transforms/BBVectorize/loop1.ll b/test/Transforms/BBVectorize/loop1.ll index 1b101e04833..8ff5953cf46 100644 --- a/test/Transforms/BBVectorize/loop1.ll +++ b/test/Transforms/BBVectorize/loop1.ll @@ -1,7 +1,7 @@ target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" target triple = "x86_64-unknown-linux-gnu" ; RUN: opt < %s -bb-vectorize -bb-vectorize-req-chain-depth=3 -bb-vectorize-ignore-target-info -instcombine -gvn -S | FileCheck %s -; RUN: opt < %s -basicaa -loop-unroll -unroll-threshold=45 -unroll-partial-threshold=45 -unroll-allow-partial -bb-vectorize -bb-vectorize-req-chain-depth=3 -bb-vectorize-ignore-target-info -instcombine -gvn -S | FileCheck %s -check-prefix=CHECK-UNRL +; RUN: opt < %s -dont-improve-non-negative-phi-bits=false -basicaa -loop-unroll -unroll-threshold=45 -unroll-partial-threshold=45 -unroll-allow-partial -bb-vectorize -bb-vectorize-req-chain-depth=3 -bb-vectorize-ignore-target-info -instcombine -gvn -S | FileCheck %s -check-prefix=CHECK-UNRL ; The second check covers the use of alias analysis (with loop unrolling). define void @test1(double* noalias %out, double* noalias %in1, double* noalias %in2) nounwind uwtable { -- 2.50.1