Disable gvn non-local speculative loads under asan.

Summary: Fix for https://llvm.org/bugs/show_bug.cgi?id=25550

Differential Revision: http://reviews.llvm.org/D14763

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253498 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index 06faa2d76b61c7a917064e7390495d11d8a69b2f..d261b2acae9e8ac6b4f08e6bd506caefc8b15433 100644 (file)
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -1701,6 +1701,10 @@ bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
 /// Attempt to eliminate a load whose dependencies are
 /// non-local by performing PHI construction.
 bool GVN::processNonLocalLoad(LoadInst *LI) {
 /// Attempt to eliminate a load whose dependencies are
 /// non-local by performing PHI construction.
 bool GVN::processNonLocalLoad(LoadInst *LI) {

+  // non-local speculations are not allowed under asan.
+  if (LI->getParent()->getParent()->hasFnAttribute(Attribute::SanitizeAddress))
+    return false;
+

   // Step 1: Find the non-local dependencies of the load.
   LoadDepVect Deps;
   MD->getNonLocalPointerDependency(LI, Deps);
   // Step 1: Find the non-local dependencies of the load.
   LoadDepVect Deps;
   MD->getNonLocalPointerDependency(LI, Deps);

diff --git a/test/Transforms/GVN/no_speculative_loads_with_asan.ll b/test/Transforms/GVN/no_speculative_loads_with_asan.ll
new file mode 100644 (file)
index 0000000..2e790db
--- /dev/null
+++ b/test/Transforms/GVN/no_speculative_loads_with_asan.ll
@@ -0,0 +1,57 @@
+; RUN: opt -O3 -S %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+declare noalias i8* @_Znam(i64) #1
+
+define i32 @TestNoAsan() {
+  %1 = tail call noalias i8* @_Znam(i64 2)
+  %2 = getelementptr inbounds i8, i8* %1, i64 1
+  store i8 0, i8* %2, align 1
+  store i8 0, i8* %1, align 1
+  %3 = bitcast i8* %1 to i16*
+  %4 = load i16, i16* %3, align 4
+  %5 = icmp eq i16 %4, 0
+  br i1 %5, label %11, label %6
+
+; <label>:6                                       ; preds = %0
+  %7 = getelementptr inbounds i8, i8* %1, i64 2
+  %8 = bitcast i8* %7 to i16*
+  %9 = load i16, i16* %8, align 2
+  %10 = sext i16 %9 to i32
+  br label %11
+
+; <label>:11                                      ; preds = %0, %6
+  %12 = phi i32 [ %10, %6 ], [ 0, %0 ]
+  ret i32 %12
+}
+
+; CHECK-LABEL: @TestNoAsan
+; CHECK: %[[LOAD:[^ ]+]] = load i32
+; CHECK: {{.*}} = ashr i32 %[[LOAD]]
+; CHECK-NOT: {{.*}} = phi
+
+define i32 @TestAsan() sanitize_address {
+  %1 = tail call noalias i8* @_Znam(i64 2)
+  %2 = getelementptr inbounds i8, i8* %1, i64 1
+  store i8 0, i8* %2, align 1
+  store i8 0, i8* %1, align 1
+  %3 = bitcast i8* %1 to i16*
+  %4 = load i16, i16* %3, align 4
+  %5 = icmp eq i16 %4, 0
+  br i1 %5, label %11, label %6
+
+; <label>:6                                       ; preds = %0
+  %7 = getelementptr inbounds i8, i8* %1, i64 2
+  %8 = bitcast i8* %7 to i16*
+  %9 = load i16, i16* %8, align 2
+  %10 = sext i16 %9 to i32
+  br label %11
+
+; <label>:11                                      ; preds = %0, %6
+  %12 = phi i32 [ %10, %6 ], [ 0, %0 ]
+  ret i32 %12
+}
+
+; CHECK-LABEL: @TestAsan
+; CHECK-NOT: %[[LOAD:[^ ]+]] = load i32
+; CHECK: {{.*}} = phi
+