[Attributor] Use the delete API for liveness

Reviewers: uenoku, sstefan1 Subscribers: hiraditya, bollu, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D66833 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@370818 91177308-0d34-0410-b5e6-96231b3b80d8
ROCm · Sep 3, 2019 · ab5d98d · ab5d98d
1 parent a5d4206
commit ab5d98d
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Showing 3 changed files with 24 additions and 16 deletions.
diff --git a/lib/Transforms/IPO/Attributor.cpp b/lib/Transforms/IPO/Attributor.cpp
@@ -1868,7 +1868,7 @@ struct AAIsDeadImpl : public AAIsDead {
     Function &F = *getAssociatedFunction();
 
     if (AssumedLiveBlocks.empty()) {
-      F.replaceAllUsesWith(UndefValue::get(F.getType()));
+      A.deleteAfterManifest(F);
       return ChangeStatus::CHANGED;
     }
 
@@ -1918,6 +1918,9 @@ struct AAIsDeadImpl : public AAIsDead {
             }
           }
         }
+
+        if (SplitPos == &NormalDestBB->front())
+          AssumedLiveBlocks.insert(NormalDestBB);
       }
 
       BB = SplitPos->getParent();
@@ -1926,6 +1929,10 @@ struct AAIsDeadImpl : public AAIsDead {
       HasChanged = ChangeStatus::CHANGED;
     }
 
+    for (BasicBlock &BB : F)
+      if (!AssumedLiveBlocks.count(&BB))
+        A.deleteAfterManifest(BB);
+
     return HasChanged;
   }
 
@@ -3309,14 +3316,18 @@ ChangeStatus Attributor::run() {
                     << " blocks and " << ToBeDeletedInsts.size()
                     << " instructions\n");
   for (Instruction *I : ToBeDeletedInsts) {
-    if (I->hasNUsesOrMore(1))
+    if (!I->use_empty())
       I->replaceAllUsesWith(UndefValue::get(I->getType()));
     I->eraseFromParent();
   }
-  for (BasicBlock *BB : ToBeDeletedBlocks) {
-    // TODO: Check if we need to replace users (PHIs, indirect branches?)
-    BB->eraseFromParent();
+
+  if (unsigned NumDeadBlocks = ToBeDeletedBlocks.size()) {
+    SmallVector<BasicBlock *, 8> ToBeDeletedBBs;
+    ToBeDeletedBBs.reserve(NumDeadBlocks);
+    ToBeDeletedBBs.append(ToBeDeletedBlocks.begin(), ToBeDeletedBlocks.end());
+    DeleteDeadBlocks(ToBeDeletedBBs);
   }
+
   for (Function *Fn : ToBeDeletedFunctions) {
     Fn->replaceAllUsesWith(UndefValue::get(Fn->getType()));
     Fn->eraseFromParent();

diff --git a/test/Transforms/FunctionAttrs/arg_returned.ll b/test/Transforms/FunctionAttrs/arg_returned.ll
@@ -804,10 +804,8 @@ attributes #0 = { noinline nounwind uwtable }
 ; BOTH-DAG: attributes #{{[0-9]*}} = { nofree noinline nosync nounwind readnone uwtable }
 ; BOTH-DAG: attributes #{{[0-9]*}} = { nofree noinline noreturn nosync nounwind readonly uwtable }
 ; BOTH-DAG: attributes #{{[0-9]*}} = { noinline nounwind uwtable }
-; BOTH-DAG: attributes #{{[0-9]*}} = { nofree noinline nosync nounwind readnone uwtable willreturn }
-; BOTH-DAG: attributes #{{[0-9]*}} = { nofree noinline nosync nounwind uwtable willreturn }
+; BOTH-DAG: attributes #{{[0-9]*}} = { noreturn }
 ; BOTH-DAG: attributes #{{[0-9]*}} = { nofree nosync willreturn }
 ; BOTH-DAG: attributes #{{[0-9]*}} = { nofree nosync }
 ; BOTH-DAG: attributes #{{[0-9]*}} = { nofree noreturn nosync }
-; BOTH-DAG: attributes #{{[0-9]*}} = { noreturn }
 ; BOTH-NOT: attributes #
diff --git a/test/Transforms/FunctionAttrs/liveness.ll b/test/Transforms/FunctionAttrs/liveness.ll
@@ -15,7 +15,7 @@ declare i32 @bar() nosync readnone
 ; This internal function has no live call sites, so all its BBs are considered dead,
 ; and nothing should be deduced for it.
 
-; CHECK: define internal i32 @dead_internal_func(i32 %0)
+; CHECK-NOT: define internal i32 @dead_internal_func(i32 %0)
 define internal i32 @dead_internal_func(i32 %0) {
   %2 = icmp slt i32 %0, 1
   br i1 %2, label %3, label %5
@@ -56,14 +56,13 @@ entry:
   call void @no_return_call()
   ; CHECK: call void @no_return_call()
   ; CHECK-NEXT: unreachable
+  ; CHECK-NEXT: }
   call i32 @dead_internal_func(i32 10)
-  ; CHECK call i32 undef(i32 10)
   %cmp = icmp eq i32 %a, 0
   br i1 %cmp, label %cond.true, label %cond.false
 
 cond.true:                                        ; preds = %entry
   call i32 @internal_load(i32* %ptr2)
-  ; CHECK: call i32 @internal_load(i32* %ptr2)
   %load = call i32 @volatile_load(i32* %ptr1)
   call void @normal_call()
   %call = call i32 @foo()
@@ -104,6 +103,8 @@ cond.false:                                       ; preds = %entry
   br label %cond.end
 
 cond.end:                                         ; preds = %cond.false, %cond.true
+; CHECK:      cond.end:
+; CHECK-NEXT:   ret i32 %call1
   %cond = phi i32 [ %call, %cond.true ], [ %call1, %cond.false ]
   ret i32 %cond
 }
@@ -120,7 +121,7 @@ cond.true:                                        ; preds = %entry
   ; CHECK: call void @no_return_call()
   ; CHECK-NEXT: unreachable
   call i32 @dead_internal_func(i32 10)
-  ; CHECK call i32 undef(i32 10)
+  ; CHECK-NOT: call
   %call = call i32 @foo()
   br label %cond.end
 
@@ -129,7 +130,7 @@ cond.false:                                       ; preds = %entry
   ; CHECK: call void @no_return_call()
   ; CHECK-NEXT: unreachable
   call i32 @dead_internal_func(i32 10)
-  ; CHECK call i32 undef(i32 10)
+  ; CHECK-NEXT: }
   %call1 = call i32 @bar()
   br label %cond.end
 
@@ -215,9 +216,7 @@ cond.true:                                        ; preds = %entry
   ; CHECK-NEXT: call i32 @foo_noreturn_nounwind()
   ; CHECK-NEXT: unreachable
 
-  ; We keep the invoke around as other attributes might have references to it.
-  ; CHECK:       cond.true.split:                                  ; No predecessors!
-  ; CHECK-NEXT:      invoke i32 @foo_noreturn_nounwind()
+  ; CHECK-NOT:      @foo_noreturn_nounwind()
 
 cond.false:                                       ; preds = %entry
   call void @normal_call()