Properly handle byval arguments in getPointerDereferenceableBytes()
Summary:
For byval arguments, the number of dereferenceable bytes is equal to
the size of the pointee, not the pointer.
Reviewers: hfinkel, rnk
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41305
llvm-svn: 320939
diff --git a/llvm/lib/IR/Value.cpp b/llvm/lib/IR/Value.cpp
index 6f67be7..eae697b 100644
--- a/llvm/lib/IR/Value.cpp
+++ b/llvm/lib/IR/Value.cpp
@@ -627,9 +627,9 @@
CanBeNull = false;
if (const Argument *A = dyn_cast<Argument>(this)) {
DerefBytes = A->getDereferenceableBytes();
- if (DerefBytes == 0 && A->hasByValAttr() && A->getType()->isSized()) {
- DerefBytes = DL.getTypeStoreSize(A->getType());
- CanBeNull = false;
+ if (DerefBytes == 0 && A->hasByValAttr()) {
+ Type *PT = cast<PointerType>(A->getType())->getElementType();
+ DerefBytes = DL.getTypeStoreSize(PT);
}
if (DerefBytes == 0) {
DerefBytes = A->getDereferenceableOrNullBytes();
diff --git a/llvm/test/Analysis/ValueTracking/memory-dereferenceable.ll b/llvm/test/Analysis/ValueTracking/memory-dereferenceable.ll
index 315a011..ca16a26 100644
--- a/llvm/test/Analysis/ValueTracking/memory-dereferenceable.ll
+++ b/llvm/test/Analysis/ValueTracking/memory-dereferenceable.ll
@@ -22,7 +22,9 @@
; CHECK-LABEL: 'test'
define void @test(i32 addrspace(1)* dereferenceable(8) %dparam,
i8 addrspace(1)* dereferenceable(32) align 1 %dparam.align1,
- i8 addrspace(1)* dereferenceable(32) align 16 %dparam.align16)
+ i8 addrspace(1)* dereferenceable(32) align 16 %dparam.align16,
+ i8* byval %i8_byval,
+ %struct.A* byval %A_byval)
gc "statepoint-example" {
; CHECK: The following are dereferenceable:
entry:
@@ -111,6 +113,18 @@
%load15 = load i8, i8 addrspace(1)* %dparam.align1, align 16
%load16 = load i8, i8 addrspace(1)* %dparam.align16, align 16
+ ; Loads from byval arguments
+; CHECK: %i8_byval{{.*}}(aligned)
+ %i8_byval_load = load i8, i8* %i8_byval
+
+; CHECK-NOT: %byval_cast
+ %byval_cast = bitcast i8* %i8_byval to i32*
+ %bad_byval_load = load i32, i32* %byval_cast
+
+; CHECK: %byval_gep{{.*}}(aligned)
+ %byval_gep = getelementptr inbounds %struct.A, %struct.A* %A_byval, i64 0, i32 1, i64 2
+ load i8, i8* %byval_gep
+
; Loads from aligned allocas
; CHECK: %alloca.align1{{.*}}(unaligned)
; CHECK: %alloca.align16{{.*}}(aligned)