[llvm] r306528 - [ValueTracking] Enabling existing ValueTracking patch by default.

[Nikolai Bozhenov via llvm-commits]

Author: n.bozhenov
Date: Wed Jun 28 03:08:08 2017
New Revision: 306528

URL: http://llvm.org/viewvc/llvm-project?rev=306528&view=rev
Log:
[ValueTracking] Enabling existing ValueTracking patch by default.

The original patch was an improvement to IR ValueTracking on non-negative
integers. It has been checked in to trunk (D18777, r284022). But was disabled by
default due to performance regressions.
Perf impact has improved. The patch would be enabled by default.

Reviewers: reames

Differential Revision: https://reviews.llvm.org/D34101

Patch by: Olga Chupina <olga.chupina at intel.com>

Modified:
    llvm/trunk/lib/Analysis/ValueTracking.cpp
    llvm/trunk/test/Transforms/BBVectorize/loop1.ll

Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=306528&r1=306527&r2=306528&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Wed Jun 28 03:08:08 2017
@@ -54,12 +54,6 @@ const unsigned MaxDepth = 6;
 static cl::opt<unsigned> 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<bool>
-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) {
@@ -1298,9 +1292,6 @@ static void computeKnownBitsFromOperator
           Known.Zero.setLowBits(std::min(Known2.countMinTrailingZeros(),
                                          Known3.countMinTrailingZeros()));
 
-          if (DontImproveNonNegativePhiBits)
-            break;
-
           auto *OverflowOp = dyn_cast<OverflowingBinaryOperator>(LU);
           if (OverflowOp && OverflowOp->hasNoSignedWrap()) {
             // If initial value of recurrence is nonnegative, and we are adding

Modified: llvm/trunk/test/Transforms/BBVectorize/loop1.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/BBVectorize/loop1.ll?rev=306528&r1=306527&r2=306528&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/BBVectorize/loop1.ll (original)
+++ llvm/trunk/test/Transforms/BBVectorize/loop1.ll Wed Jun 28 03:08:08 2017
@@ -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 -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
+; 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
 ; 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 {