[InstCombine] Preserve return attributes when merging llvm.ptrmask

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

Differential Revision: https://reviews.llvm.org/D156638

Author: goldsteinn

llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

@@ -1968,17 +1968,23 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
       return II;
 
     Value *InnerPtr, *InnerMask;
+    bool Changed = false;
+    // Combine:
+    // (ptrmask (ptrmask p, A), B)
+    //    -> (ptrmask p, (and A, B))
     if (match(II->getArgOperand(0),
               m_OneUse(m_Intrinsic<Intrinsic::ptrmask>(m_Value(InnerPtr),
                                                        m_Value(InnerMask))))) {
       assert(II->getArgOperand(1)->getType() == InnerMask->getType() &&
              "Mask types must match");
+      // TODO: If InnerMask == Op1, we could copy attributes from inner
+      // callsite -> outer callsite.
       Value *NewMask = Builder.CreateAnd(II->getArgOperand(1), InnerMask);
-      return replaceInstUsesWith(
-          *II, Builder.CreateIntrinsic(InnerPtr->getType(), Intrinsic::ptrmask,
-                                       {InnerPtr, NewMask}));
+      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() ||

llvm/test/Transforms/InstCombine/ptrmask.ll

@@ -12,7 +12,7 @@ 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)
@@ -24,7 +24,7 @@ define <2 x ptr> @ptrmask_combine_consecutive_preserve_attrs_vecs(<2 x ptr> %p0,
 ; CHECK-LABEL: define <2 x ptr> @ptrmask_combine_consecutive_preserve_attrs_vecs
 ; CHECK-SAME: (<2 x ptr> [[P0:%.*]], <2 x i64> [[M1:%.*]]) {
 ; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i64> [[M1]], <i64 12345, i64 12345>
-; CHECK-NEXT:    [[R:%.*]] = call <2 x ptr> @llvm.ptrmask.v2p0.v2i64(<2 x ptr> [[P0]], <2 x i64> [[TMP1]])
+; CHECK-NEXT:    [[R:%.*]] = call align 128 <2 x ptr> @llvm.ptrmask.v2p0.v2i64(<2 x ptr> [[P0]], <2 x i64> [[TMP1]])
 ; CHECK-NEXT:    ret <2 x ptr> [[R]]
 ;
   %pm0 = call <2 x ptr> @llvm.ptrmask.v2p0.v2i64(<2 x ptr> %p0, <2 x i64> <i64 12345, i64 12345>)