[InstCombine] Preserve return attributes when merging `llvm.ptrmask`

[goldstein.w.n]

Summary

If we have assosiated attributes i.e `([ret_attrs] (ptrmask (ptrmask
p0, m0), m1)) we should preserve [ret_attrs]` when combining the two
llvm.ptrmasks.

[goldstein.w.n]

This has been ported to github PR.

llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

case Intrinsic::ptrmask: {
     // Fail loudly in case this is ever changed.
     // TODO: If vector types are supported the merging of (ptrmask (ptrmask))
     // need to ensure we don't merge a vectype with non-vec type.
     assert(!Op0->getType()->isVectorTy() && !Op1->getType()->isVectorTy() &&
            "These combines where written at a time when ptrmask did not "
            "support vector types and may not work for vectors");
 
     Value *InnerPtr, *InnerMask;
-    if (match(II->getArgOperand(0),
-              m_OneUse(m_Intrinsic<Intrinsic::ptrmask>(m_Value(InnerPtr),
-                                                       m_Value(InnerMask))))) {
-      if (II->getArgOperand(1)->getType() == InnerMask->getType()) {
-        Value *NewMask = Builder.CreateAnd(II->getArgOperand(1), InnerMask);
-        return replaceInstUsesWith(
-            *II,
-            Builder.CreateIntrinsic(InnerPtr->getType(), Intrinsic::ptrmask,
-                                    {InnerPtr, NewMask}));
+    bool Changed = false;
+    // Combine:
+    // (ptrmask (ptrmask p, A), B)
+    //    -> (ptrmask p, (and A, B))
+    if (match(Op0, m_OneUse(m_Intrinsic<Intrinsic::ptrmask>(
+                       m_Value(InnerPtr), m_Value(InnerMask))))) {
+      if (InnerMask->getType() == Op1->getType()) {
+        // TODO: If InnerMask == Op1, we could copy attributes from inner
+        // callsite -> outer callsite.
+        Value *NewMask = Builder.CreateAnd(Op1, InnerMask);
+        replaceOperand(CI, 0, InnerPtr);
+        replaceOperand(CI, 1, NewMask);
+        Changed = true;
       }
     }
-    bool Changed = false;
     // See if we can deduce non-null.
     if (!CI.hasRetAttr(Attribute::NonNull) &&
         (Known.isNonZero() ||
          isKnownNonZero(II, DL, /*Depth*/ 0, &AC, II, &DT))) {
       CI.addRetAttr(Attribute::NonNull);
       Changed = true;
     }
 

llvm/test/Transforms/InstCombine/ptrmask.ll

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
 ; RUN: opt < %s -passes=instcombine -S | FileCheck %s
 
 declare ptr @llvm.ptrmask.p0.i32(ptr, i32)
 declare ptr @llvm.ptrmask.p0.i64(ptr, i64)
 
 define ptr @ptrmask_combine_consecutive_preserve_attrs(ptr %p0, i64 %m1) {
 ; CHECK-LABEL: define ptr @ptrmask_combine_consecutive_preserve_attrs
 ; CHECK-SAME: (ptr [[P0:%.*]], i64 [[M1:%.*]]) {
 ; CHECK-NEXT:    [[TMP1:%.*]] = and i64 [[M1]], 224
-; CHECK-NEXT:    [[R:%.*]] = call align 32 ptr @llvm.ptrmask.p0.i64(ptr [[P0]], i64 [[TMP1]])
+; CHECK-NEXT:    [[R:%.*]] = call noalias align 32 ptr @llvm.ptrmask.p0.i64(ptr [[P0]], i64 [[TMP1]])
 ; CHECK-NEXT:    ret ptr [[R]]
 ;
   %pm0 = call ptr @llvm.ptrmask.p0.i64(ptr %p0, i64 224)
   %r = call noalias ptr @llvm.ptrmask.p0.i64(ptr %pm0, i64 %m1)
   ret ptr %r
 }
 
 define ptr @ptrmask_combine_consecutive_preserve_attrs_fail(ptr %p0, i64 %m0) {