[llvm] [Attributor] Propagate alignment through ptrmask (PR #150158)

Matt Arsenault via llvm-commits llvm-commits at lists.llvm.org
Thu Sep 11 06:12:09 PDT 2025


================
@@ -5187,6 +5187,59 @@ struct AADereferenceableCallSiteReturned final
 // ------------------------ Align Argument Attribute ------------------------
 
 namespace {
+
+Align getKnownAlignForIntrinsic(Attributor &A, AAAlign &QueryingAA,
+                                const IntrinsicInst &II) {
+  switch (II.getIntrinsicID()) {
+  case Intrinsic::ptrmask: {
+    const auto *ConstVals = A.getAAFor<AAPotentialConstantValues>(
+        QueryingAA, IRPosition::value(*(II.getOperand(1))), DepClassTy::NONE);
+    const auto *AlignAA = A.getAAFor<AAAlign>(QueryingAA, IRPosition::value(II),
+                                              DepClassTy::NONE);
+    if (ConstVals && ConstVals->isValidState() && ConstVals->isAtFixpoint()) {
+      unsigned ShiftValue =
+          std::min(ConstVals->getAssumedMinTrailingZeros(), (unsigned)63);
+      Align ConstAlign(1 << ShiftValue);
+      if (ConstAlign >= AlignAA->getKnownAlign())
+        return Align(1);
+    }
+    if (AlignAA)
+      return AlignAA->getKnownAlign();
+    break;
+  }
+  default:
+    break;
+  }
+  return Align(1);
+}
+
+Align getAssumedAlignForIntrinsic(Attributor &A, AAAlign &QueryingAA,
+                                  const IntrinsicInst &II) {
+  Align Alignment;
+  switch (II.getIntrinsicID()) {
+  case Intrinsic::ptrmask: {
+    const auto *ConstVals = A.getAAFor<AAPotentialConstantValues>(
+        QueryingAA, IRPosition::value(*(II.getOperand(1))),
----------------
arsenm wrote:

```suggestion
        QueryingAA, IRPosition::value(*II.getArgOperand(1)),
```

https://github.com/llvm/llvm-project/pull/150158


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