[value-tracking] see through returned attribute.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D109675

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 53d7ddf..8d18d13 100644 (file)
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -4533,6 +4533,12 @@ AllocaInst *llvm::findAllocaForValue(Value *V, bool OffsetZero) {
       if (OffsetZero && !GEP->hasAllZeroIndices())
         return nullptr;
       AddWork(GEP->getPointerOperand());
+    } else if (CallBase *CB = dyn_cast<CallBase>(V)) {
+      Value *Returned = CB->getReturnedArgOperand();
+      if (Returned)
+        AddWork(Returned);
+      else
+        return nullptr;
     } else {
       return nullptr;
     }

diff --git a/llvm/test/Instrumentation/HWAddressSanitizer/stack-safety-analysis.ll b/llvm/test/Instrumentation/HWAddressSanitizer/stack-safety-analysis.ll
index b14445b..51d7cb5 100644 (file)
--- a/llvm/test/Instrumentation/HWAddressSanitizer/stack-safety-analysis.ll
+++ b/llvm/test/Instrumentation/HWAddressSanitizer/stack-safety-analysis.ll
@@ -164,8 +164,7 @@ entry:
   ; SAFETY: call {{.*}}__hwasan_generate_tag
   ; SAFETY-NOT: call {{.*}}__hwasan_store
   ; NOSTACK-NOT: call {{.*}}__hwasan_generate_tag
-  ; TODO: Do not emit this store.
-  ; NOSTACK: call {{.*}}__hwasan_store
+  ; NOSTACK-NOT: call {{.*}}__hwasan_store
   %buf.sroa.0 = alloca i8, align 4
   call void @llvm.lifetime.start.p0i8(i64 1, i8* nonnull %buf.sroa.0)
   %ptr = call i8* @retptr(i8* %buf.sroa.0)

diff --git a/llvm/unittests/Analysis/ValueTrackingTest.cpp b/llvm/unittests/Analysis/ValueTrackingTest.cpp
index c07c76c..4c4067e 100644 (file)
--- a/llvm/unittests/Analysis/ValueTrackingTest.cpp
+++ b/llvm/unittests/Analysis/ValueTrackingTest.cpp
@@ -2256,6 +2256,22 @@ const FindAllocaForValueTestParams FindAllocaForValueTests[] = {
         ret void
       })",
      false, false},
+    {R"(
+      declare i32* @retptr(i32* returned)
+      define void @test(i1 %cond) {
+        %a = alloca i32
+        %r = call i32* @retptr(i32* %a)
+        ret void
+      })",
+     true, true},
+    {R"(
+      declare i32* @fun(i32*)
+      define void @test(i1 %cond) {
+        %a = alloca i32
+        %r = call i32* @fun(i32* %a)
+        ret void
+      })",
+     false, false},
 };
 
 TEST_P(FindAllocaForValueTest, findAllocaForValue) {