!fixup move code to getOptionalSinkBlockForInst.

Author: fhahn

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -5413,18 +5413,6 @@ bool InstCombinerImpl::tryToSinkInstruction(Instruction *I,
         return false;
   }
 
-  // Do not sink if there are dereferenceable assumes that would be removed.
-  for (User *User : I->users()) {
-    auto *CI = dyn_cast<CallInst>(User);
-    if (!CI || CI->getParent() == DestBlock)
-      continue;
-
-    if (CI->getIntrinsicID() == Intrinsic::assume &&
-        CI->getOperandBundle("dereferenceable")) {
-      return false;
-    }
-  }
-
   I->dropDroppableUses([&](const Use *U) {
     auto *I = dyn_cast<Instruction>(U->getUser());
     if (I && I->getParent() != DestBlock) {
@@ -5636,8 +5624,15 @@ bool InstCombinerImpl::run() {
 
       for (Use &U : I->uses()) {
         User *User = U.getUser();
-        if (User->isDroppable())
-          continue;
+        if (User->isDroppable()) {
+          // Do not sink if there are dereferenceable assumes that would be
+          // removed.
+          auto II = dyn_cast<IntrinsicInst>(User);
+          if (II->getIntrinsicID() != Intrinsic::assume ||
+              !II->getOperandBundle("dereferenceable"))
+            continue;
+        }
+
         if (NumUsers > MaxSinkNumUsers)
           return std::nullopt;
 

llvm/test/Transforms/InstCombine/sink-dereferenceable-assume.ll

@@ -5,6 +5,11 @@ define i64 @test_dereferenceable_assume(ptr %p, ptr %q, i1 %c.0) {
 ; CHECK-LABEL: define i64 @test_dereferenceable_assume(
 ; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]], i1 [[C_0:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[P_INT:%.*]] = ptrtoint ptr [[P]] to i64
+; CHECK-NEXT:    [[Q_INT:%.*]] = ptrtoint ptr [[Q]] to i64
+; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[Q_INT]], [[P_INT]]
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 [[DIFF]]) ]
+; CHECK-NEXT:    br i1 [[C_0]], label %[[THEN:.*]], label %[[ELSE:.*]]
 ; CHECK:       [[THEN]]:
 ; CHECK-NEXT:    ret i64 [[DIFF]]
 ; CHECK:       [[ELSE]]:
@@ -56,13 +61,14 @@ define i64 @test_sink_with_multiple_users_dominated_by_deref(ptr %p, ptr %q, i1
 ; CHECK-LABEL: define i64 @test_sink_with_multiple_users_dominated_by_deref(
 ; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]], i1 [[C_0:%.*]], i1 [[C_1:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[P_INT:%.*]] = ptrtoint ptr [[P]] to i64
+; CHECK-NEXT:    [[Q_INT:%.*]] = ptrtoint ptr [[Q]] to i64
+; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[Q_INT]], [[P_INT]]
 ; CHECK-NEXT:    br i1 [[C_0]], label %[[THEN:.*]], label %[[ELSE:.*]]
 ; CHECK:       [[THEN]]:
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 [[DIFF]]) ]
 ; CHECK-NEXT:    br i1 [[C_1]], label %[[THEN_2:.*]], label %[[ELSE]]
 ; CHECK:       [[THEN_2]]:
-; CHECK-NEXT:    [[Q_INT:%.*]] = ptrtoint ptr [[Q]] to i64
-; CHECK-NEXT:    [[P_INT:%.*]] = ptrtoint ptr [[P]] to i64
-; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[Q_INT]], [[P_INT]]
 ; CHECK-NEXT:    [[DOUBLED:%.*]] = shl i64 [[DIFF]], 1
 ; CHECK-NEXT:    ret i64 [[DOUBLED]]
 ; CHECK:       [[ELSE]]:
@@ -90,13 +96,14 @@ define i64 @test_deref_user_does_not_dominate_other_user(ptr %p, ptr %q, i1 %c.0
 ; CHECK-LABEL: define i64 @test_deref_user_does_not_dominate_other_user(
 ; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]], i1 [[C_0:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[P_INT:%.*]] = ptrtoint ptr [[P]] to i64
+; CHECK-NEXT:    [[Q_INT:%.*]] = ptrtoint ptr [[Q]] to i64
+; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[Q_INT]], [[P_INT]]
 ; CHECK-NEXT:    br i1 [[C_0]], label %[[MIDDLE:.*]], label %[[EXIT:.*]]
 ; CHECK:       [[MIDDLE]]:
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 [[DIFF]]) ]
 ; CHECK-NEXT:    br label %[[EXIT]]
 ; CHECK:       [[EXIT]]:
-; CHECK-NEXT:    [[Q_INT:%.*]] = ptrtoint ptr [[Q]] to i64
-; CHECK-NEXT:    [[P_INT:%.*]] = ptrtoint ptr [[P]] to i64
-; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[Q_INT]], [[P_INT]]
 ; CHECK-NEXT:    ret i64 [[DIFF]]
 ;
 entry: