From d9389827d21ba1adf0663d4122acfa467b2d7ad8 Mon Sep 17 00:00:00 2001
From: Yaxun Liu <Yaxun.Liu@amd.com>
Date: Wed, 14 Mar 2018 15:02:28 +0000
Subject: [PATCH] CodeGen: Reduce LValue and CallArgList memory footprint
 before recommitting r326946

Recent change r326946 (https://reviews.llvm.org/D34367) causes regression in Eigen due to increased
memory footprint of CallArg.

This patch reduces LValue size from 112 to 96 bytes and reduces inline argument count of CallArgList
from 16 to 8.

It has been verified that this will let the added deep AST tree test pass with r326946.

In the long run, CallArg or LValue memory footprint should be further optimized.

Differential Revision: https://reviews.llvm.org/D44445

llvm-svn: 327515
---
 clang/lib/CodeGen/CGCall.h  |  2 +-
 clang/lib/CodeGen/CGValue.h | 13 ++++++++-----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/clang/lib/CodeGen/CGCall.h b/clang/lib/CodeGen/CGCall.h
index 495baf0..1cac032 100644
--- a/clang/lib/CodeGen/CGCall.h
+++ b/clang/lib/CodeGen/CGCall.h
@@ -224,7 +224,7 @@ public:
   /// CallArgList - Type for representing both the value and type of
   /// arguments in a call.
   class CallArgList :
-    public SmallVector<CallArg, 16> {
+    public SmallVector<CallArg, 8> {
   public:
     CallArgList() : StackBase(nullptr) {}
 
diff --git a/clang/lib/CodeGen/CGValue.h b/clang/lib/CodeGen/CGValue.h
index 7d07ea4..a32be19 100644
--- a/clang/lib/CodeGen/CGValue.h
+++ b/clang/lib/CodeGen/CGValue.h
@@ -193,7 +193,7 @@ class LValue {
 
   // The alignment to use when accessing this lvalue.  (For vector elements,
   // this is the alignment of the whole vector.)
-  int64_t Alignment;
+  unsigned Alignment;
 
   // objective-c's ivar
   bool Ivar:1;
@@ -215,13 +215,13 @@ class LValue {
   // to make the default bitfield pattern all-zeroes.
   bool ImpreciseLifetime : 1;
 
-  LValueBaseInfo BaseInfo;
-  TBAAAccessInfo TBAAInfo;
-
   // This flag shows if a nontemporal load/stores should be used when accessing
   // this lvalue.
   bool Nontemporal : 1;
 
+  LValueBaseInfo BaseInfo;
+  TBAAAccessInfo TBAAInfo;
+
   Expr *BaseIvarExp;
 
 private:
@@ -231,7 +231,10 @@ private:
            "initializing l-value with zero alignment!");
     this->Type = Type;
     this->Quals = Quals;
-    this->Alignment = Alignment.getQuantity();
+    const unsigned MaxAlign = 1U << 31;
+    this->Alignment = Alignment.getQuantity() <= MaxAlign
+                          ? Alignment.getQuantity()
+                          : MaxAlign;
     assert(this->Alignment == Alignment.getQuantity() &&
            "Alignment exceeds allowed max!");
     this->BaseInfo = BaseInfo;
-- 
2.7.4