From 91e7c14953a2b18b93a7e3282956dfcbb1204874 Mon Sep 17 00:00:00 2001
From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Fri, 27 May 2016 19:03:10 +0000
Subject: [PATCH] [GVN] Preserve !range metadata when PRE'ing loads

Reviewers: dberlin, reames, george.burgess.iv

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D20743

llvm-svn: 271034
---
 lib/Transforms/Scalar/GVN.cpp        |  2 ++
 test/Transforms/GVN/load-metadata.ll | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 test/Transforms/GVN/load-metadata.ll

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index 97ec1eab654..5236c526e75 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -1567,6 +1567,8 @@ bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
       NewLoad->setMetadata(LLVMContext::MD_invariant_load, MD);
     if (auto *InvGroupMD = LI->getMetadata(LLVMContext::MD_invariant_group))
       NewLoad->setMetadata(LLVMContext::MD_invariant_group, InvGroupMD);
+    if (auto *RangeMD = LI->getMetadata(LLVMContext::MD_range))
+      NewLoad->setMetadata(LLVMContext::MD_range, RangeMD);
 
     // Transfer DebugLoc.
     NewLoad->setDebugLoc(LI->getDebugLoc());
diff --git a/test/Transforms/GVN/load-metadata.ll b/test/Transforms/GVN/load-metadata.ll
new file mode 100644
index 00000000000..3294cda7ee9
--- /dev/null
+++ b/test/Transforms/GVN/load-metadata.ll
@@ -0,0 +1,24 @@
+; RUN: opt -S -gvn < %s | FileCheck %s
+
+define i32 @test1(i32* %p, i1 %C) {
+; CHECK-LABEL: @test1(
+block1:
+	br i1 %C, label %block2, label %block3
+
+block2:
+ br label %block4
+; CHECK: block2:
+; CHECK-NEXT: load i32, i32* %p, !range !0, !invariant.group !1
+
+block3:
+  store i32 0, i32* %p
+  br label %block4
+
+block4:
+  %PRE = load i32, i32* %p, !range !0, !invariant.group !1
+  ret i32 %PRE
+}
+
+
+!0 = !{i32 40, i32 100}
+!1 = !{!"magic ptr"}