[clang] [InstCombine] Add combines/simplifications for `llvm.ptrmask` (PR #67166)

[Yingwei Zheng via cfe-commits]

================
@@ -1964,18 +1964,78 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
     break;
   }
   case Intrinsic::ptrmask: {
+    KnownBits Known(DL.getPointerTypeSizeInBits(II->getType()));
+    if (SimplifyDemandedInstructionBits(*II, Known))
+      return II;
+
+    Value *Op0 = II->getArgOperand(0);
+    Value *Op1 = II->getArgOperand(1);
+    // 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))))) {
+      // See if combining the two masks is free.
+      bool OkayToMerge = InnerMask->getType() == Op1->getType();
+      bool NeedsNew = false;
+      if (!OkayToMerge) {
+        if (match(InnerMask, m_ImmConstant())) {
+          InnerMask = Builder.CreateZExtOrTrunc(InnerMask, Op1->getType());
+          OkayToMerge = true;
+        } else if (match(Op1, m_ImmConstant())) {
+          Op1 = Builder.CreateZExtOrTrunc(Op1, InnerMask->getType());
+          OkayToMerge = true;
+          // Need to create a new one here, as the intrinsic id needs to change.
+          NeedsNew = true;
+        }
+      }
+      if (InnerMask->getType() == Op1->getType()) {
----------------
dtcxzyw wrote:

`OkayToMerge` is unused?

https://github.com/llvm/llvm-project/pull/67166