[PATCH] D156640: [InstCombine] Fold `(ptrtoint (ptrmask p0, m0))` -> `(and (ptrtoint p0), m0)`

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n created this revision.
goldstein.w.n added reviewers: nikic, RKSimon.
Herald added subscribers: StephenFan, hiraditya, arichardson.
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goldstein.w.n requested review of this revision.
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`and` is generally more supported so if we have a `ptrmask` anyways
might as well use `and`.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D156640

Files:
  llvm/lib/Transforms/InstCombine/InstCombineCasts.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
@@ -118,8 +118,8 @@
 define i64 @ptrtoint_of_ptrmask(ptr %p, i64 %m) {
 ; CHECK-LABEL: define i64 @ptrtoint_of_ptrmask
 ; CHECK-SAME: (ptr [[P:%.*]], i64 [[M:%.*]]) {
-; CHECK-NEXT:    [[PM:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[P]], i64 [[M]])
-; CHECK-NEXT:    [[R:%.*]] = ptrtoint ptr [[PM]] to i64
+; CHECK-NEXT:    [[TMP1:%.*]] = ptrtoint ptr [[P]] to i64
+; CHECK-NEXT:    [[R:%.*]] = and i64 [[TMP1]], [[M]]
 ; CHECK-NEXT:    ret i64 [[R]]
 ;
   %pm = call ptr @llvm.ptrmask.p0.i64(ptr %p, i64 %m)
@@ -131,9 +131,9 @@
 define i32 @ptrtoint_of_ptrmask2(ptr %p, i64 %m) {
 ; CHECK-LABEL: define i32 @ptrtoint_of_ptrmask2
 ; CHECK-SAME: (ptr [[P:%.*]], i64 [[M:%.*]]) {
-; CHECK-NEXT:    [[PM:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[P]], i64 [[M]])
-; CHECK-NEXT:    [[TMP1:%.*]] = ptrtoint ptr [[PM]] to i64
-; CHECK-NEXT:    [[R:%.*]] = trunc i64 [[TMP1]] to i32
+; CHECK-NEXT:    [[TMP1:%.*]] = ptrtoint ptr [[P]] to i64
+; CHECK-NEXT:    [[TMP2:%.*]] = and i64 [[TMP1]], [[M]]
+; CHECK-NEXT:    [[R:%.*]] = trunc i64 [[TMP2]] to i32
 ; CHECK-NEXT:    ret i32 [[R]]
 ;
   %pm = call ptr @llvm.ptrmask.p0.i64(ptr %p, i64 %m)
Index: llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -1955,6 +1955,15 @@
     return CastInst::CreateIntegerCast(P, Ty, /*isSigned=*/false);
   }
 
+  // (ptrtoint (ptrmask P, M))
+  //    -> (and (ptrtoint P), M)
+  // This is generally beneficial as `and` is better supported than `ptrmask`.
+  Value *Ptr, *Mask;
+  if (match(SrcOp, m_OneUse(m_Intrinsic<Intrinsic::ptrmask>(m_Value(Ptr),
+                                                            m_Value(Mask)))) &&
+      Mask->getType() == Ty)
+    return BinaryOperator::CreateAnd(Builder.CreatePtrToInt(Ptr, Ty), Mask);
+
   if (auto *GEP = dyn_cast<GetElementPtrInst>(SrcOp)) {
     // Fold ptrtoint(gep null, x) to multiply + constant if the GEP has one use.
     // While this can increase the number of instructions it doesn't actually


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