[WIP] Consider datalayout sentinel pointer value for isKnownNonZero check

llvm/lib/Analysis/ValueTracking.cpp

@@ -3098,6 +3098,13 @@ bool isKnownNonZero(const Value *V, const APInt &DemandedElts,
   // Check for pointer simplifications.
 
   if (PointerType *PtrTy = dyn_cast<PointerType>(Ty)) {
+    const DataLayout &DL = Q.DL;
+    if (DL.isSentinelValueDefined()) {
+      unsigned AddrSpace = PtrTy->getPointerAddressSpace();
+
+      return (DL.getSentinelPointerValue(AddrSpace) != 0);
+    }
+
     // A byval, inalloca may not be null in a non-default addres space. A
     // nonnull argument is assumed never 0.
     if (const Argument *A = dyn_cast<Argument>(V)) {

llvm/test/Transforms/Attributor/IPConstantProp/pthreads-dl-sentinel.ll

@@ -0,0 +1,151 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --function-signature --check-attributes --check-globals
+; RUN: opt -aa-pipeline=basic-aa -passes=attributor-cgscc -attributor-manifest-internal  -attributor-annotate-decl-cs -S < %s | FileCheck %s --check-prefixes=CHECK,CGSCC
+; RUN: opt -aa-pipeline=basic-aa -passes=attributor-cgscc -attributor-manifest-internal  -attributor-annotate-decl-cs -data-layout=z0:1-z2:neg1-z3:neg1-z5:neg1 -S < %s | FileCheck %s --check-prefixes=CHECK-DL,CGSCC-DL
+;
+;    #include <pthread.h>
+;
+;    ptr GlobalVPtr;
+;
+;    static ptr foo(ptr arg) { return arg; }
+;    static ptr bar(ptr arg) { return arg; }
+;
+;    int main() {
+;      pthread_t thread;
+;      pthread_create(&thread, NULL, foo, NULL);
+;      pthread_create(&thread, NULL, bar, &GlobalVPtr);
+;      return 0;
+;    }
+;
+; Verify the constant values NULL and &GlobalVPtr are propagated into foo and
+; bar, respectively.
+;
+
+%union.pthread_attr_t = type { i64, [48 x i8] }
+
+@GlobalVPtr = common dso_local global ptr null, align 8
+
+; FIXME: nocapture & noalias for @GlobalVPtr in %call1
+; FIXME: nocapture & noalias for %alloc2 in %call3
+
+;.
+; CHECK: @GlobalVPtr = common dso_local global ptr null, align 8
+;.
+; CHECK-DL: @GlobalVPtr = common dso_local global ptr null, align 8
+;.
+define dso_local i32 @main() {
+; CHECK-LABEL: define {{[^@]+}}@main() {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ALLOC1:%.*]] = alloca i8, align 8
+; CHECK-NEXT:    [[ALLOC2:%.*]] = alloca i8, align 8
+; CHECK-NEXT:    [[THREAD:%.*]] = alloca i64, align 8
+; CHECK-NEXT:    [[CALL:%.*]] = call i32 @pthread_create(ptr noundef nonnull align 8 dereferenceable(8) [[THREAD]], ptr noundef align 4294967296 null, ptr noundef nonnull @foo, ptr nofree noundef readnone align 4294967296 null)
+; CHECK-NEXT:    [[CALL1:%.*]] = call i32 @pthread_create(ptr noundef nonnull align 8 dereferenceable(8) [[THREAD]], ptr noundef align 4294967296 null, ptr noundef nonnull @bar, ptr noalias nocapture nofree noundef nonnull readnone align 8 dereferenceable(8) @GlobalVPtr)
+; CHECK-NEXT:    [[CALL2:%.*]] = call i32 @pthread_create(ptr noundef nonnull align 8 dereferenceable(8) [[THREAD]], ptr noundef align 4294967296 null, ptr noundef nonnull @baz, ptr noalias nocapture nofree noundef nonnull readnone align 8 dereferenceable(1) [[ALLOC1]])
+; CHECK-NEXT:    [[CALL3:%.*]] = call i32 @pthread_create(ptr noundef nonnull align 8 dereferenceable(8) [[THREAD]], ptr noundef align 4294967296 null, ptr noundef nonnull @buz, ptr noalias nofree noundef nonnull readnone align 8 dereferenceable(1) [[ALLOC2]])
+; CHECK-NEXT:    ret i32 0
+;
+; CHECK-DL-LABEL: define {{[^@]+}}@main() {
+; CHECK-DL-NEXT:  entry:
+; CHECK-DL-NEXT:    [[ALLOC1:%.*]] = alloca i8, align 8
+; CHECK-DL-NEXT:    [[ALLOC2:%.*]] = alloca i8, align 8
+; CHECK-DL-NEXT:    [[THREAD:%.*]] = alloca i64, align 8
+; CHECK-DL-NEXT:    unreachable
+;
+entry:
+  %alloc1 = alloca i8, align 8
+  %alloc2 = alloca i8, align 8
+  %thread = alloca i64, align 8
+  %call = call i32 @pthread_create(ptr nonnull %thread, ptr null, ptr nonnull @foo, ptr null)
+  %call1 = call i32 @pthread_create(ptr nonnull %thread, ptr null, ptr nonnull @bar, ptr @GlobalVPtr)
+  %call2 = call i32 @pthread_create(ptr nonnull %thread, ptr null, ptr nonnull @baz, ptr nocapture %alloc1)
+  %call3 = call i32 @pthread_create(ptr nonnull %thread, ptr null, ptr nonnull @buz, ptr %alloc2)
+  ret i32 0
+}
+
+declare !callback !0 dso_local i32 @pthread_create(ptr, ptr, ptr, ptr)
+
+define internal ptr @foo(ptr %arg) {
+; CHECK: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
+; CHECK-LABEL: define {{[^@]+}}@foo
+; CHECK-SAME: (ptr noalias nocapture nofree readnone align 4294967296 [[ARG:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret ptr null
+;
+; CHECK-DL: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
+; CHECK-DL-LABEL: define {{[^@]+}}@foo
+; CHECK-DL-SAME: (ptr noalias nocapture nofree nonnull readnone align 4294967296 [[ARG:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-DL-NEXT:  entry:
+; CHECK-DL-NEXT:    unreachable
+;
+entry:
+  ret ptr %arg
+}
+
+
+define internal ptr @bar(ptr %arg) {
+; CHECK: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
+; CHECK-LABEL: define {{[^@]+}}@bar
+; CHECK-SAME: (ptr noalias nocapture nofree nonnull readnone align 8 dereferenceable(8) [[ARG:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret ptr @GlobalVPtr
+;
+; CHECK-DL: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
+; CHECK-DL-LABEL: define {{[^@]+}}@bar
+; CHECK-DL-SAME: (ptr noalias nocapture nofree nonnull readnone align 8 dereferenceable(8) [[ARG:%.*]]) #[[ATTR0]] {
+; CHECK-DL-NEXT:  entry:
+; CHECK-DL-NEXT:    ret ptr @GlobalVPtr
+;
+entry:
+  ret ptr %arg
+}
+
+define internal ptr @baz(ptr %arg) {
+; CHECK: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
+; CHECK-LABEL: define {{[^@]+}}@baz
+; CHECK-SAME: (ptr noalias nofree noundef nonnull readnone returned align 8 dereferenceable(1) "no-capture-maybe-returned" [[ARG:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret ptr [[ARG]]
+;
+; CHECK-DL: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
+; CHECK-DL-LABEL: define {{[^@]+}}@baz
+; CHECK-DL-SAME: (ptr noalias nofree noundef nonnull readnone returned align 8 dereferenceable(1) "no-capture-maybe-returned" [[ARG:%.*]]) #[[ATTR0]] {
+; CHECK-DL-NEXT:  entry:
+; CHECK-DL-NEXT:    ret ptr [[ARG]]
+;
+entry:
+  ret ptr %arg
+}
+
+define internal ptr @buz(ptr %arg) {
+; CHECK: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
+; CHECK-LABEL: define {{[^@]+}}@buz
+; CHECK-SAME: (ptr noalias nofree noundef nonnull readnone returned align 8 dereferenceable(1) "no-capture-maybe-returned" [[ARG:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret ptr [[ARG]]
+;
+; CHECK-DL: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
+; CHECK-DL-LABEL: define {{[^@]+}}@buz
+; CHECK-DL-SAME: (ptr noalias nofree noundef nonnull readnone returned align 8 dereferenceable(1) "no-capture-maybe-returned" [[ARG:%.*]]) #[[ATTR0]] {
+; CHECK-DL-NEXT:  entry:
+; CHECK-DL-NEXT:    ret ptr [[ARG]]
+;
+entry:
+  ret ptr %arg
+}
+
+!1 = !{i64 2, i64 3, i1 false}
+!0 = !{!1}
+;.
+; CHECK: attributes #[[ATTR0]] = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) }
+;.
+; CHECK-DL: attributes #[[ATTR0]] = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) }
+;.
+; CHECK: [[META0:![0-9]+]] = !{[[META1:![0-9]+]]}
+; CHECK: [[META1]] = !{i64 2, i64 3, i1 false}
+;.
+; CHECK-DL: [[META0:![0-9]+]] = !{[[META1:![0-9]+]]}
+; CHECK-DL: [[META1]] = !{i64 2, i64 3, i1 false}
+;.
+;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
+; CGSCC: {{.*}}
+; CGSCC-DL: {{.*}}