[llvm] c316675 - [LLVMContextImpl] Separate out integer constant zeroes

[Arthur Eubanks via llvm-commits]

Author: Arthur Eubanks
Date: 2023-02-27T10:18:39-08:00
New Revision: c31667539bc6bf6c7d56c88f216291b1d9a203b9

URL: https://github.com/llvm/llvm-project/commit/c31667539bc6bf6c7d56c88f216291b1d9a203b9
DIFF: https://github.com/llvm/llvm-project/commit/c31667539bc6bf6c7d56c88f216291b1d9a203b9.diff

LOG: [LLVMContextImpl] Separate out integer constant zeroes

Very small compile time improvement:
https://llvm-compile-time-tracker.com/compare.php?from=a628ca4925f7249b4fbd3e932c9627b12e2770dd&to=6a7a8907e8334eaf551742148079c628f78e6ed7&stat=instructions:u

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D144745

Added: 
    

Modified: 
    llvm/lib/IR/Constants.cpp
    llvm/lib/IR/LLVMContextImpl.cpp
    llvm/lib/IR/LLVMContextImpl.h

Removed: 
    


################################################################################
diff  --git a/llvm/lib/IR/Constants.cpp b/llvm/lib/IR/Constants.cpp
index a53671183f77c..6efc66d0983c7 100644
--- a/llvm/lib/IR/Constants.cpp
+++ b/llvm/lib/IR/Constants.cpp
@@ -874,7 +874,9 @@ Constant *ConstantInt::getBool(Type *Ty, bool V) {
 ConstantInt *ConstantInt::get(LLVMContext &Context, const APInt &V) {
   // get an existing value or the insertion position
   LLVMContextImpl *pImpl = Context.pImpl;
-  std::unique_ptr<ConstantInt> &Slot = pImpl->IntConstants[V];
+  std::unique_ptr<ConstantInt> &Slot =
+      V.isZero() ? pImpl->IntZeroConstants[V.getBitWidth()]
+                 : pImpl->IntConstants[V];
   if (!Slot) {
     // Get the corresponding integer type for the bit width of the value.
     IntegerType *ITy = IntegerType::get(Context, V.getBitWidth());

diff  --git a/llvm/lib/IR/LLVMContextImpl.cpp b/llvm/lib/IR/LLVMContextImpl.cpp
index 9acb1f654899f..98157e6a8fa59 100644
--- a/llvm/lib/IR/LLVMContextImpl.cpp
+++ b/llvm/lib/IR/LLVMContextImpl.cpp
@@ -116,6 +116,7 @@ LLVMContextImpl::~LLVMContextImpl() {
   CTNConstants.clear();
   UVConstants.clear();
   PVConstants.clear();
+  IntZeroConstants.clear();
   IntConstants.clear();
   FPConstants.clear();
   CDSConstants.clear();

diff  --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index d2651a6ec72e2..f828ea9c69f9b 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -1446,13 +1446,12 @@ class LLVMContextImpl {
 
   DenseMap<const Value *, ValueName *> ValueNames;
 
-  using IntMapTy =
-      DenseMap<APInt, std::unique_ptr<ConstantInt>, DenseMapAPIntKeyInfo>;
-  IntMapTy IntConstants;
+  DenseMap<unsigned, std::unique_ptr<ConstantInt>> IntZeroConstants;
+  DenseMap<APInt, std::unique_ptr<ConstantInt>, DenseMapAPIntKeyInfo>
+      IntConstants;
 
-  using FPMapTy =
-      DenseMap<APFloat, std::unique_ptr<ConstantFP>, DenseMapAPFloatKeyInfo>;
-  FPMapTy FPConstants;
+  DenseMap<APFloat, std::unique_ptr<ConstantFP>, DenseMapAPFloatKeyInfo>
+      FPConstants;
 
   FoldingSet<AttributeImpl> AttrsSet;
   FoldingSet<AttributeListImpl> AttrsLists;