From a0c9f6e73622e7f040d827850acbdfcbde945998 Mon Sep 17 00:00:00 2001
From: Philip Reames <listmail@philipreames.com>
Date: Fri, 4 Mar 2016 22:27:39 +0000
Subject: [PATCH] [LVI] Fix a bug which prevented use of !range metadata within
 a query

The diff is relatively large since I took a chance to rearrange the code I had to touch in a more obvious way, but the key bit is merely using the !range metadata when we can't analyze the instruction further.  The previous !range metadata code was essentially just dead since no binary operator or cast will have !range metadata (per Verifier) and it was otherwise dropped on the floor.

llvm-svn: 262751
---
 llvm/lib/Analysis/LazyValueInfo.cpp           | 32 ++++++-------------
 .../CorrelatedValuePropagation/range.ll       | 14 ++++++++
 2 files changed, 24 insertions(+), 22 deletions(-)

diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index b2ce163fca36c..467f46489070f 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -669,36 +669,24 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) {
     return true;
   }
 
-  // If this is an instruction which supports range metadata, intersect the
-  // implied range.
-  Res = intersect(Res, getFromRangeMetadata(BBI));
-
-  // We can only analyze the definitions of certain classes of instructions
-  // (integral binops and casts at the moment), so bail if this isn't one.
-  LVILatticeVal Result;
-  if ((!isa<BinaryOperator>(BBI) && !isa<CastInst>(BBI)) ||
-     !BBI->getType()->isIntegerTy()) {
-    DEBUG(dbgs() << " compute BB '" << BB->getName()
-                 << "' - overdefined because inst def found.\n");
-    Res.markOverdefined();
+  if (isa<CastInst>(BBI) && BBI->getType()->isIntegerTy()) {
+    if (!solveBlockValueConstantRange(Res, BBI, BB))
+      return false;
     insertResult(Val, BB, Res);
     return true;
   }
 
-  // FIXME: We're currently limited to binops with a constant RHS.  This should
-  // be improved.
   BinaryOperator *BO = dyn_cast<BinaryOperator>(BBI);
-  if (BO && !isa<ConstantInt>(BO->getOperand(1))) { 
-    DEBUG(dbgs() << " compute BB '" << BB->getName()
-                 << "' - overdefined because inst def found.\n");
-
-    Res.markOverdefined();
+  if (BO && isa<ConstantInt>(BO->getOperand(1))) { 
+    if (!solveBlockValueConstantRange(Res, BBI, BB))
+      return false;
     insertResult(Val, BB, Res);
     return true;
   }
 
-  if (!solveBlockValueConstantRange(Res, BBI, BB))
-    return false;
+  DEBUG(dbgs() << " compute BB '" << BB->getName()
+                 << "' - unknown inst def found.\n");
+  Res = getFromRangeMetadata(BBI);
   insertResult(Val, BB, Res);
   return true;
 }
@@ -1007,7 +995,7 @@ bool LazyValueInfoCache::solveBlockValueSelect(LVILatticeVal &BBLV,
 
 bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV,
                                                       Instruction *BBI,
-                                                      BasicBlock *BB) {
+                                                      BasicBlock *BB) {  
   // Figure out the range of the LHS.  If that fails, bail.
   if (!hasBlockValue(BBI->getOperand(0), BB)) {
     if (pushBlockValue(std::make_pair(BB, BBI->getOperand(0))))
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/range.ll b/llvm/test/Transforms/CorrelatedValuePropagation/range.ll
index 884cc8bdc125b..8ca171a286ccd 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/range.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/range.ll
@@ -189,3 +189,17 @@ define i1 @test10(i64* %p) {
   %res = icmp eq i64 %a, 0
   ret i1 %res
 }
+
+@g = external global i32
+
+define i1 @test11() {
+; CHECK: @test11
+; CHECK: ret i1 true
+  %positive = load i32, i32* @g, !range !{i32 1, i32 2048}
+  %add = add i32 %positive, 1
+  %test = icmp sgt i32 %add, 0
+  br label %next
+
+next:
+  ret i1 %test
+}