From: Justin Lebar <jlebar@google.com>
Date: Sat, 16 Jun 2018 00:13:57 +0000 (+0000)
Subject: Revert "[SCEV] Simplify some flags expressions." -- dependent revision breaks MSVC... 
X-Git-Tag: android-x86-8.1-r1~2035
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=e743a53c301379bbdb09d2ad83e44ab88460269d;p=android-x86%2Fexternal-llvm.git

Revert "[SCEV] Simplify some flags expressions." -- dependent revision breaks MSVC builds.

This reverts D48238.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@334877 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index c60035198f3..a1566cb5e86 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -3897,7 +3897,7 @@ const SCEV *ScalarEvolution::getMinusSCEV(const SCEV *LHS, const SCEV *RHS,
   auto AddFlags = SCEV::FlagAnyWrap;
   const bool RHSIsNotMinSigned =
       !getSignedRangeMin(RHS).isMinSignedValue();
-  if (Flags & SCEV::FlagNSW) {
+  if ((Flags & SCEV::FlagNSW) == SCEV::FlagNSW) {
     // Let M be the minimum representable signed value. Then (-1)*RHS
     // signed-wraps if and only if RHS is M. That can happen even for
     // a NSW subtraction because e.g. (-1)*M signed-wraps even though
@@ -11940,7 +11940,7 @@ bool SCEVWrapPredicate::isAlwaysTrue() const {
   SCEV::NoWrapFlags ScevFlags = AR->getNoWrapFlags();
   IncrementWrapFlags IFlags = Flags;
 
-  if (ScevFlags & SCEV::FlagNSW)
+  if ((ScevFlags | SCEV::FlagNSW) == ScevFlags)
     IFlags &= ~IncrementNSSW;
 
   return IFlags == IncrementAnyWrap;
@@ -11962,10 +11962,10 @@ SCEVWrapPredicate::getImpliedFlags(const SCEVAddRecExpr *AR,
   SCEV::NoWrapFlags StaticFlags = AR->getNoWrapFlags();
 
   // We can safely transfer the NSW flag as NSSW.
-  if (StaticFlags & SCEV::FlagNSW)
+  if ((StaticFlags | SCEV::FlagNSW) == StaticFlags)
     ImpliedFlags = IncrementNSSW;
 
-  if (StaticFlags & SCEV::FlagNUW) {
+  if ((StaticFlags | SCEV::FlagNUW) == StaticFlags) {
     // If the increment is positive, the SCEV NUW flag will also imply the
     // WrapPredicate NUSW flag.
     if (const auto *Step = dyn_cast<SCEVConstant>(AR->getStepRecurrence(SE)))