[PATCH] D156638: [InstCombine] Preserve return attributes when merging `llvm.ptrmask`

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n created this revision.
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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.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D156638

Files:
  llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
  llvm/test/Transforms/InstCombine/ptrmask.ll


Index: llvm/test/Transforms/InstCombine/ptrmask.ll
===================================================================
--- llvm/test/Transforms/InstCombine/ptrmask.ll
+++ llvm/test/Transforms/InstCombine/ptrmask.ll
@@ -8,7 +8,7 @@
 ; 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)
Index: llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1944,18 +1944,21 @@
            "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() ||


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