[PATCH] D85379: Reduce dropTriviallyDeadConstantArrays cumulative time percentage from 17% to 4%

[Teresa Johnson via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGaedaa077f58d: Reduce dropTriviallyDeadConstantArrays cumulative time percentage from 17% to 4% (authored by Jianzhou Zhao <jianzhouzh at google.com>, committed by tejohnson).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D85379/new/

https://reviews.llvm.org/D85379

Files:
  llvm/lib/IR/LLVMContextImpl.cpp


Index: llvm/lib/IR/LLVMContextImpl.cpp
===================================================================
--- llvm/lib/IR/LLVMContextImpl.cpp
+++ llvm/lib/IR/LLVMContextImpl.cpp
@@ -129,8 +129,15 @@
 }
 
 void LLVMContextImpl::dropTriviallyDeadConstantArrays() {
-  SmallSetVector<ConstantArray *, 4> WorkList(ArrayConstants.begin(),
-                                              ArrayConstants.end());
+  SmallSetVector<ConstantArray *, 4> WorkList;
+
+  // When ArrayConstants are of substantial size and only a few in them are
+  // dead, starting WorkList with all elements of ArrayConstants can be
+  // wasteful. Instead, starting WorkList with only elements that have empty
+  // uses.
+  for (ConstantArray *C : ArrayConstants)
+    if (C->use_empty())
+      WorkList.insert(C);
 
   while (!WorkList.empty()) {
     ConstantArray *C = WorkList.pop_back_val();


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D85379.283966.patch
Type: text/x-patch
Size: 872 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20200807/fdf957c7/attachment.bin>