From 881a05b46c28299046bd0dc3d0b8c6677e68a4d7 Mon Sep 17 00:00:00 2001
From: Andrew Trick <atrick@apple.com>
Date: Wed, 7 Nov 2012 07:05:05 +0000
Subject: misched: handle on-the-fly regpressure queries better for 2-addr
 instructions without relying on liveintervals.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167526 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/CodeGen/RegisterPressure.h |  3 ++-
 lib/CodeGen/RegisterPressure.cpp        | 21 +++++++++++++--------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/include/llvm/CodeGen/RegisterPressure.h b/include/llvm/CodeGen/RegisterPressure.h
index 2043155bc5..30326d05df 100644
--- a/include/llvm/CodeGen/RegisterPressure.h
+++ b/include/llvm/CodeGen/RegisterPressure.h
@@ -43,7 +43,7 @@ struct RegisterPressure {
   /// class. This is only useful to account for spilling or rematerialization.
   void decrease(const TargetRegisterClass *RC, const TargetRegisterInfo *TRI);
 
-  void dump(const TargetRegisterInfo *TRI);
+  void dump(const TargetRegisterInfo *TRI) const;
 };
 
 /// RegisterPressure computed within a region of instructions delimited by
@@ -197,6 +197,7 @@ public:
   /// This result is complete if either advance() or recede() has returned true,
   /// or if closeRegion() was explicitly invoked.
   RegisterPressure &getPressure() { return P; }
+  const RegisterPressure &getPressure() const { return P; }
 
   /// Get the register set pressure at the current position, which may be less
   /// than the pressure across the traversed region.
diff --git a/lib/CodeGen/RegisterPressure.cpp b/lib/CodeGen/RegisterPressure.cpp
index 94779770e0..543c426458 100644
--- a/lib/CodeGen/RegisterPressure.cpp
+++ b/lib/CodeGen/RegisterPressure.cpp
@@ -64,7 +64,7 @@ void RegisterPressure::decrease(const TargetRegisterClass *RC,
 }
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-void RegisterPressure::dump(const TargetRegisterInfo *TRI) {
+void RegisterPressure::dump(const TargetRegisterInfo *TRI) const {
   dbgs() << "Live In: ";
   for (unsigned i = 0, e = LiveInRegs.size(); i < e; ++i)
     dbgs() << PrintReg(LiveInRegs[i], TRI) << " ";
@@ -322,10 +322,8 @@ struct RegisterOperands {
         if (findReg(MO.getReg(), isVReg, DeadDefs, TRI) == DeadDefs.end())
           DeadDefs.push_back(MO.getReg());
       }
-      else {
-        if (findReg(MO.getReg(), isVReg, Defs, TRI) == Defs.end())
-          Defs.push_back(MO.getReg());
-      }
+      else if (findReg(MO.getReg(), isVReg, Defs, TRI) == Defs.end())
+        Defs.push_back(MO.getReg());
     }
   }
 };
@@ -676,9 +674,16 @@ void RegPressureTracker::bumpUpwardPressure(const MachineInstr *MI) {
   decreaseVirtRegPressure(VirtRegOpers.DeadDefs);
 
   // Kill liveness at live defs.
-  decreasePhysRegPressure(PhysRegOpers.Defs);
-  decreaseVirtRegPressure(VirtRegOpers.Defs);
-
+  for (unsigned i = 0, e = PhysRegOpers.Defs.size(); i < e; ++i) {
+    unsigned Reg = PhysRegOpers.Defs[i];
+    if (!findReg(Reg, false, PhysRegOpers.Uses, TRI))
+      decreasePhysRegPressure(PhysRegOpers.Defs);
+  }
+  for (unsigned i = 0, e = VirtRegOpers.Defs.size(); i < e; ++i) {
+    unsigned Reg = VirtRegOpers.Defs[i];
+    if (!findReg(Reg, true, VirtRegOpers.Uses, TRI))
+      decreaseVirtRegPressure(VirtRegOpers.Defs);
+  }
   // Generate liveness for uses.
   for (unsigned i = 0, e = PhysRegOpers.Uses.size(); i < e; ++i) {
     unsigned Reg = PhysRegOpers.Uses[i];
-- 
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