[Attributor] `byval` arguments are always `noalias`

`byval` introduces a local copy of the argument. That copy cannot alias
anything.

8 files changed, 23 insertions, 15 deletions

diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index 5eb21a0..19dc998 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -2386,6 +2386,14 @@ struct AANoAliasArgument final
   using Base = AAArgumentFromCallSiteArguments<AANoAlias, AANoAliasImpl>;
   AANoAliasArgument(const IRPosition &IRP) : Base(IRP) {}
 
+  /// See AbstractAttribute::initialize(...).
+  void initialize(Attributor &A) override {
+    Base::initialize(A);
+    // See callsite argument attribute and callee argument attribute.
+    if (hasAttr({Attribute::ByVal}))
+      indicateOptimisticFixpoint();
+  }
+
   /// See AbstractAttribute::update(...).
   ChangeStatus updateImpl(Attributor &A) override {
     // We have to make sure no-alias on the argument does not break
diff --git a/llvm/test/Transforms/Attributor/ArgumentPromotion/attrs.ll b/llvm/test/Transforms/Attributor/ArgumentPromotion/attrs.ll
index 8f2e14d..ac9b076 100644
--- a/llvm/test/Transforms/Attributor/ArgumentPromotion/attrs.ll
+++ b/llvm/test/Transforms/Attributor/ArgumentPromotion/attrs.ll
@@ -6,7 +6,7 @@
 ; Don't drop 'byval' on %X here.
 define internal void @f(%struct.ss* byval %b, i32* byval %X, i32 %i) nounwind {
 ; CHECK-LABEL: define {{[^@]+}}@f
-; CHECK-SAME: (%struct.ss* noalias nocapture nofree nonnull byval align 8 dereferenceable(12) [[B:%.*]], i32* nocapture nofree nonnull writeonly byval dereferenceable(4) [[X:%.*]], i32 [[I:%.*]])
+; CHECK-SAME: (%struct.ss* noalias nocapture nofree nonnull byval align 8 dereferenceable(12) [[B:%.*]], i32* noalias nocapture nofree nonnull writeonly byval dereferenceable(4) [[X:%.*]], i32 [[I:%.*]])
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[TMP:%.*]] = getelementptr [[STRUCT_SS:%.*]], %struct.ss* [[B]], i32 0, i32 0
 ; CHECK-NEXT:    [[TMP1:%.*]] = load i32, i32* [[TMP]], align 8
diff --git a/llvm/test/Transforms/Attributor/ArgumentPromotion/byval-2.ll b/llvm/test/Transforms/Attributor/ArgumentPromotion/byval-2.ll
index 2ebf5ec..12e02f8 100644
--- a/llvm/test/Transforms/Attributor/ArgumentPromotion/byval-2.ll
+++ b/llvm/test/Transforms/Attributor/ArgumentPromotion/byval-2.ll
@@ -5,7 +5,7 @@
 
 define internal void @f(%struct.ss* byval  %b, i32* byval %X) nounwind  {
 ; CHECK-LABEL: define {{[^@]+}}@f
-; CHECK-SAME: (%struct.ss* noalias nocapture nofree nonnull byval align 8 dereferenceable(12) [[B:%.*]], i32* nocapture nofree nonnull writeonly byval dereferenceable(4) [[X:%.*]])
+; CHECK-SAME: (%struct.ss* noalias nocapture nofree nonnull byval align 8 dereferenceable(12) [[B:%.*]], i32* noalias nocapture nofree nonnull writeonly byval dereferenceable(4) [[X:%.*]])
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[TMP:%.*]] = getelementptr [[STRUCT_SS:%.*]], %struct.ss* [[B]], i32 0, i32 0
 ; CHECK-NEXT:    [[TMP1:%.*]] = load i32, i32* [[TMP]], align 8
diff --git a/llvm/test/Transforms/Attributor/ArgumentPromotion/fp80.ll b/llvm/test/Transforms/Attributor/ArgumentPromotion/fp80.ll
index 153ce689..6a6864b 100644
--- a/llvm/test/Transforms/Attributor/ArgumentPromotion/fp80.ll
+++ b/llvm/test/Transforms/Attributor/ArgumentPromotion/fp80.ll
@@ -48,7 +48,7 @@ define internal i64 @AccessPaddingOfStruct(%struct.Foo* byval %a) {
 
 define internal i64 @CaptureAStruct(%struct.Foo* byval %a) {
 ; CHECK-LABEL: define {{[^@]+}}@CaptureAStruct
-; CHECK-SAME: (%struct.Foo* nofree nonnull byval align 8 dereferenceable(16) [[A:%.*]])
+; CHECK-SAME: (%struct.Foo* noalias nofree nonnull byval align 8 dereferenceable(16) [[A:%.*]])
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[A_PTR:%.*]] = alloca %struct.Foo*
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
diff --git a/llvm/test/Transforms/Attributor/ArgumentPromotion/tail.ll b/llvm/test/Transforms/Attributor/ArgumentPromotion/tail.ll
index 2a34bde..6f55d4a 100644
--- a/llvm/test/Transforms/Attributor/ArgumentPromotion/tail.ll
+++ b/llvm/test/Transforms/Attributor/ArgumentPromotion/tail.ll
@@ -10,7 +10,7 @@ declare i8* @foo(%pair*)
 
 define internal void @bar(%pair* byval %Data) {
 ; CHECK-LABEL: define {{[^@]+}}@bar
-; CHECK-SAME: (%pair* byval [[DATA:%.*]])
+; CHECK-SAME: (%pair* noalias byval [[DATA:%.*]])
 ; CHECK-NEXT:    [[TMP1:%.*]] = tail call i8* @foo(%pair* [[DATA]])
 ; CHECK-NEXT:    ret void
 ;
@@ -20,8 +20,8 @@ define internal void @bar(%pair* byval %Data) {
 
 define void @zed(%pair* byval %Data) {
 ; CHECK-LABEL: define {{[^@]+}}@zed
-; CHECK-SAME: (%pair* nocapture readonly byval [[DATA:%.*]])
-; CHECK-NEXT:    call void @bar(%pair* nocapture readonly byval [[DATA]])
+; CHECK-SAME: (%pair* noalias nocapture readonly byval [[DATA:%.*]])
+; CHECK-NEXT:    call void @bar(%pair* noalias nocapture readonly byval [[DATA]])
 ; CHECK-NEXT:    ret void
 ;
   call void @bar(%pair* byval %Data)
diff --git a/llvm/test/Transforms/Attributor/IPConstantProp/2009-09-24-byval-ptr.ll b/llvm/test/Transforms/Attributor/IPConstantProp/2009-09-24-byval-ptr.ll
index 8616794f..55175d70 100644
--- a/llvm/test/Transforms/Attributor/IPConstantProp/2009-09-24-byval-ptr.ll
+++ b/llvm/test/Transforms/Attributor/IPConstantProp/2009-09-24-byval-ptr.ll
@@ -6,7 +6,7 @@
 @mystr = internal global %struct.MYstr zeroinitializer ; <%struct.MYstr*> [#uses=3]
 define internal void @vfu1(%struct.MYstr* byval align 4 %u) nounwind {
 ; CHECK-LABEL: define {{[^@]+}}@vfu1
-; CHECK-SAME: (%struct.MYstr* nocapture nofree nonnull writeonly byval align 8 dereferenceable(8) [[U:%.*]])
+; CHECK-SAME: (%struct.MYstr* noalias nocapture nofree nonnull writeonly byval align 8 dereferenceable(8) [[U:%.*]])
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr [[STRUCT_MYSTR:%.*]], %struct.MYstr* [[U]], i32 0, i32 1
 ; CHECK-NEXT:    store i32 99, i32* [[TMP0]], align 4
@@ -29,7 +29,7 @@ return:                                           ; preds = %entry
 
 define internal i32 @vfu2(%struct.MYstr* byval align 4 %u) nounwind readonly {
 ; CHECK-LABEL: define {{[^@]+}}@vfu2
-; CHECK-SAME: (%struct.MYstr* nocapture nofree nonnull readonly byval align 8 dereferenceable(8) [[U:%.*]])
+; CHECK-SAME: (%struct.MYstr* noalias nocapture nofree nonnull readonly byval align 8 dereferenceable(8) [[U:%.*]])
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr [[STRUCT_MYSTR:%.*]], %struct.MYstr* @mystr, i32 0, i32 1
 ; CHECK-NEXT:    [[TMP1:%.*]] = load i32, i32* [[TMP0]]
@@ -64,7 +64,7 @@ entry:
 
 define internal i32 @vfu2_v2(%struct.MYstr* byval align 4 %u) nounwind readonly {
 ; CHECK-LABEL: define {{[^@]+}}@vfu2_v2
-; CHECK-SAME: (%struct.MYstr* nocapture nofree nonnull byval align 8 dereferenceable(8) [[U:%.*]])
+; CHECK-SAME: (%struct.MYstr* noalias nocapture nofree nonnull byval align 8 dereferenceable(8) [[U:%.*]])
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[Z:%.*]] = getelementptr [[STRUCT_MYSTR:%.*]], %struct.MYstr* [[U]], i32 0, i32 1
 ; CHECK-NEXT:    store i32 99, i32* [[Z]], align 4
diff --git a/llvm/test/Transforms/Attributor/readattrs.ll b/llvm/test/Transforms/Attributor/readattrs.ll
index cfb4f71..aa272a3 100644
--- a/llvm/test/Transforms/Attributor/readattrs.ll
+++ b/llvm/test/Transforms/Attributor/readattrs.ll
@@ -150,35 +150,35 @@ define void @unsound_readonly(i8* %ignored, i8* %escaped_then_written) {
 declare void @escape_i8(i8* %ptr)
 
 ; ATTRIBUTOR:      @byval_not_readonly_1
-; ATTRIBUTOR-SAME: i8* byval %written
+; ATTRIBUTOR-SAME: i8* noalias byval %written
 define void @byval_not_readonly_1(i8* byval %written) readonly {
   call void @escape_i8(i8* %written)
   ret void
 }
 
 ; ATTRIBUTOR:      @byval_not_readonly_2
-; ATTRIBUTOR-SAME: i8* nocapture nofree nonnull writeonly byval dereferenceable(1) %written
+; ATTRIBUTOR-SAME: i8* noalias nocapture nofree nonnull writeonly byval dereferenceable(1) %written
 define void @byval_not_readonly_2(i8* byval %written) readonly {
   store i8 0, i8* %written
   ret void
 }
 
 ; ATTRIBUTOR:      @byval_not_readnone_1
-; ATTRIBUTOR-SAME: i8* byval %written
+; ATTRIBUTOR-SAME: i8* noalias byval %written
 define void @byval_not_readnone_1(i8* byval %written) readnone {
   call void @escape_i8(i8* %written)
   ret void
 }
 
 ; ATTRIBUTOR:      @byval_not_readnone_2
-; ATTRIBUTOR-SAME: i8* nocapture nofree nonnull writeonly byval dereferenceable(1) %written
+; ATTRIBUTOR-SAME: i8* noalias nocapture nofree nonnull writeonly byval dereferenceable(1) %written
 define void @byval_not_readnone_2(i8* byval %written) readnone {
   store i8 0, i8* %written
   ret void
 }
 
 ; ATTRIBUTOR:      @byval_no_fnarg
-; ATTRIBUTOR-SAME: i8* nocapture nofree nonnull writeonly byval dereferenceable(1) %written
+; ATTRIBUTOR-SAME: i8* noalias nocapture nofree nonnull writeonly byval dereferenceable(1) %written
 define void @byval_no_fnarg(i8* byval %written) {
   store i8 0, i8* %written
   ret void
diff --git a/llvm/test/Transforms/Attributor/value-simplify.ll b/llvm/test/Transforms/Attributor/value-simplify.ll
index 046521a..b2563ad0 100644
--- a/llvm/test/Transforms/Attributor/value-simplify.ll
+++ b/llvm/test/Transforms/Attributor/value-simplify.ll
@@ -246,7 +246,7 @@ define %struct.X* @complicated_args_nest() {
 @S = external global %struct.X
 define internal void @test_byval(%struct.X* byval %a) {
 ; CHECK-LABEL: define {{[^@]+}}@test_byval
-; CHECK-SAME: (%struct.X* nocapture nofree nonnull writeonly byval align 8 dereferenceable(8) [[A:%.*]])
+; CHECK-SAME: (%struct.X* noalias nocapture nofree nonnull writeonly byval align 8 dereferenceable(8) [[A:%.*]])
 ; CHECK-NEXT:    [[G0:%.*]] = getelementptr [[STRUCT_X:%.*]], %struct.X* [[A]], i32 0, i32 0
 ; CHECK-NEXT:    store i8* null, i8** [[G0]], align 8
 ; CHECK-NEXT:    ret void