From ad48e01eef196d0a19739c9109c44c4ea251a5db Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Tue, 7 Sep 2010 05:39:02 +0000
Subject: Add completely hokey binary-and and binary-or operations to
 ConstantRange and teach LazyValueInfo to use them.

llvm-svn: 113196
---
 llvm/lib/Analysis/LazyValueInfo.cpp |  6 ++++++
 llvm/lib/Support/ConstantRange.cpp  | 26 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

(limited to 'llvm/lib')

diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index 9c3878b7759..2c25f80dbea 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -602,6 +602,12 @@ LVILatticeVal LVIQuery::getBlockValue(BasicBlock *BB) {
   case Instruction::BitCast:
     Result.markConstantRange(LHSRange);
     break;
+  case Instruction::And:
+    Result.markConstantRange(LHSRange.binaryAnd(RHSRange));
+    break;
+  case Instruction::Or:
+    Result.markConstantRange(LHSRange.binaryOr(RHSRange));
+    break;
   
   // Unhandled instructions are overdefined.
   default:
diff --git a/llvm/lib/Support/ConstantRange.cpp b/llvm/lib/Support/ConstantRange.cpp
index defb8189b62..c89ec9a2aac 100644
--- a/llvm/lib/Support/ConstantRange.cpp
+++ b/llvm/lib/Support/ConstantRange.cpp
@@ -607,6 +607,32 @@ ConstantRange::udiv(const ConstantRange &RHS) const {
   return ConstantRange(Lower, Upper);
 }
 
+ConstantRange
+ConstantRange::binaryAnd(const ConstantRange &Other) const {
+  if (isEmptySet() || Other.isEmptySet())
+    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
+
+  // TODO: replace this with something less conservative
+
+  APInt umin = APIntOps::umin(Other.getUnsignedMax(), getUnsignedMax());
+  if (umin.isAllOnesValue())
+    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
+  return ConstantRange(APInt::getNullValue(getBitWidth()), umin + 1);
+}
+
+ConstantRange
+ConstantRange::binaryOr(const ConstantRange &Other) const {
+  if (isEmptySet() || Other.isEmptySet())
+    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
+
+  // TODO: replace this with something less conservative
+
+  APInt umax = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
+  if (umax.isMinValue())
+    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
+  return ConstantRange(umax, APInt::getNullValue(getBitWidth()));
+}
+
 ConstantRange
 ConstantRange::shl(const ConstantRange &Other) const {
   if (isEmptySet() || Other.isEmptySet())
-- 
cgit v1.2.3