From: Igor Laevsky <igmyrj@gmail.com>
Date: Fri, 18 Sep 2015 13:01:48 +0000 (+0000)
Subject: [LazyValueInfo] Report nonnull range for nonnull pointers
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=ef40e27a137c69442c230cc3a52065c4007ecf71

[LazyValueInfo] Report nonnull range for nonnull pointers

Currently LazyValueInfo will report only alloca's as having nonnull range.
For loads with !nonnull metadata it will bailout with no additional information.
Same is true for calls returning nonnull pointers.

This change extends LazyValueInfo to handle additional nonnull instructions.

Differential Revision: http://reviews.llvm.org/D12932



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247985 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/LazyValueInfo.cpp b/lib/Analysis/LazyValueInfo.cpp
index 7fc3e5afe48..795e3987c0d 100644
--- a/lib/Analysis/LazyValueInfo.cpp
+++ b/lib/Analysis/LazyValueInfo.cpp
@@ -531,8 +531,10 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) {
     return true;
   }
 
-  if (AllocaInst *AI = dyn_cast<AllocaInst>(BBI)) {
-    Res = LVILatticeVal::getNot(ConstantPointerNull::get(AI->getType()));
+  // If this value is a nonnull pointer, record it's range and bailout.
+  PointerType *PT = dyn_cast<PointerType>(BBI->getType());
+  if (PT && isKnownNonNull(BBI)) {
+    Res = LVILatticeVal::getNot(ConstantPointerNull::get(PT));
     insertResult(Val, BB, Res);
     return true;
   }
diff --git a/test/Transforms/CorrelatedValuePropagation/non-null.ll b/test/Transforms/CorrelatedValuePropagation/non-null.ll
index a24dfb67ca1..6fb4cb6e358 100644
--- a/test/Transforms/CorrelatedValuePropagation/non-null.ll
+++ b/test/Transforms/CorrelatedValuePropagation/non-null.ll
@@ -140,3 +140,24 @@ merge:
   ; CHECK: call void @test11_helper(i8* nonnull %merged_arg)
   ret void
 }
+
+declare void @test12_helper(i8* %arg)
+define void @test12(i8* %arg1, i8** %arg2) {
+; CHECK-LABEL: @test12
+entry:
+  %is_null = icmp eq i8* %arg1, null
+  br i1 %is_null, label %null, label %non_null
+
+non_null:
+  br label %merge
+
+null:
+  %another_arg = load i8*, i8** %arg2, !nonnull !{}
+  br label %merge
+
+merge:
+  %merged_arg = phi i8* [%another_arg, %null], [%arg1, %non_null]
+  call void @test12_helper(i8* %merged_arg)
+  ; CHECK: call void @test12_helper(i8* nonnull %merged_arg)
+  ret void
+}