From 5945447d84320a8361be006e63dc942862adac63 Mon Sep 17 00:00:00 2001
From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Wed, 19 Apr 2017 18:21:09 +0000
Subject: [PATCH] [GVN] Don't coerce non-integral pointers to integers or vice
 versa

Summary:
See http://llvm.org/docs/LangRef.html#non-integral-pointer-type

The NewGVN test does not fail without these changes (perhaps it does
try to coerce pointers <-> integers to begin with?), but I added the
test case anyway.

Reviewers: dberlin

Subscribers: mcrosier, llvm-commits, Prazek

Differential Revision: https://reviews.llvm.org/D32208

llvm-svn: 300730
---
 llvm/lib/Transforms/Utils/VNCoercion.cpp           |  5 +++
 llvm/test/Transforms/GVN/non-integral-pointers.ll  | 39 ++++++++++++++++++++++
 .../Transforms/NewGVN/non-integral-pointers.ll     | 39 ++++++++++++++++++++++
 3 files changed, 83 insertions(+)
 create mode 100644 llvm/test/Transforms/GVN/non-integral-pointers.ll
 create mode 100644 llvm/test/Transforms/NewGVN/non-integral-pointers.ll

diff --git a/llvm/lib/Transforms/Utils/VNCoercion.cpp b/llvm/lib/Transforms/Utils/VNCoercion.cpp
index 4aeea02..83bd29d 100644
--- a/llvm/lib/Transforms/Utils/VNCoercion.cpp
+++ b/llvm/lib/Transforms/Utils/VNCoercion.cpp
@@ -24,6 +24,11 @@ bool canCoerceMustAliasedValueToLoad(Value *StoredVal, Type *LoadTy,
   if (DL.getTypeSizeInBits(StoredVal->getType()) < DL.getTypeSizeInBits(LoadTy))
     return false;
 
+  // Don't coerce non-integral pointers to integers or vice versa.
+  if (DL.isNonIntegralPointerType(StoredVal->getType()) !=
+      DL.isNonIntegralPointerType(LoadTy))
+    return false;
+
   return true;
 }
 
diff --git a/llvm/test/Transforms/GVN/non-integral-pointers.ll b/llvm/test/Transforms/GVN/non-integral-pointers.ll
new file mode 100644
index 0000000..9ae4132
--- /dev/null
+++ b/llvm/test/Transforms/GVN/non-integral-pointers.ll
@@ -0,0 +1,39 @@
+; RUN: opt -gvn -S < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128-ni:4"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @f0(i1 %alwaysFalse, i64 %val, i64* %loc) {
+; CHECK-LABEL: @f0(
+; CHECK-NOT: inttoptr
+; CHECK-NOT: ptrtoint
+ entry:
+  store i64 %val, i64* %loc
+  br i1 %alwaysFalse, label %neverTaken, label %alwaysTaken
+
+ neverTaken:
+  %loc.bc = bitcast i64* %loc to i8 addrspace(4)**
+  %ptr = load i8 addrspace(4)*, i8 addrspace(4)** %loc.bc
+  store i8 5, i8 addrspace(4)* %ptr
+  ret void
+
+ alwaysTaken:
+  ret void
+}
+
+define i64 @f1(i1 %alwaysFalse, i8 addrspace(4)* %val, i8 addrspace(4)** %loc) {
+; CHECK-LABEL: @f1(
+; CHECK-NOT: inttoptr
+; CHECK-NOT: ptrtoint
+ entry:
+  store i8 addrspace(4)* %val, i8 addrspace(4)** %loc
+  br i1 %alwaysFalse, label %neverTaken, label %alwaysTaken
+
+ neverTaken:
+  %loc.bc = bitcast i8 addrspace(4)** %loc to i64*
+  %int = load i64, i64* %loc.bc
+  ret i64 %int
+
+ alwaysTaken:
+  ret i64 42
+}
diff --git a/llvm/test/Transforms/NewGVN/non-integral-pointers.ll b/llvm/test/Transforms/NewGVN/non-integral-pointers.ll
new file mode 100644
index 0000000..75b8285
--- /dev/null
+++ b/llvm/test/Transforms/NewGVN/non-integral-pointers.ll
@@ -0,0 +1,39 @@
+; RUN: opt -newgvn -S < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128-ni:4"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @f0(i1 %alwaysFalse, i64 %val, i64* %loc) {
+; CHECK-LABEL: @f0(
+; CHECK-NOT: inttoptr
+; CHECK-NOT: ptrtoint
+ entry:
+  store i64 %val, i64* %loc
+  br i1 %alwaysFalse, label %neverTaken, label %alwaysTaken
+
+ neverTaken:
+  %loc.bc = bitcast i64* %loc to i8 addrspace(4)**
+  %ptr = load i8 addrspace(4)*, i8 addrspace(4)** %loc.bc
+  store i8 5, i8 addrspace(4)* %ptr
+  ret void
+
+ alwaysTaken:
+  ret void
+}
+
+define i64 @f1(i1 %alwaysFalse, i8 addrspace(4)* %val, i8 addrspace(4)** %loc) {
+; CHECK-LABEL: @f1(
+; CHECK-NOT: inttoptr
+; CHECK-NOT: ptrtoint
+ entry:
+  store i8 addrspace(4)* %val, i8 addrspace(4)** %loc
+  br i1 %alwaysFalse, label %neverTaken, label %alwaysTaken
+
+ neverTaken:
+  %loc.bc = bitcast i8 addrspace(4)** %loc to i64*
+  %int = load i64, i64* %loc.bc
+  ret i64 %int
+
+ alwaysTaken:
+  ret i64 42
+}
-- 
2.7.4