From 72d7c270698e67ceba9ce41fd6b1266fbf65050b Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 17 Apr 2006 21:22:06 +0000
Subject: [PATCH] Vectors that are known live-in and live-out are clearly
 already marked in the vrsave register for the caller.  This allows us to
 codegen a function as:

_test_rol:
        mfspr r2, 256
        mr r3, r2
        mtspr 256, r3
        vspltisw v2, -12
        vrlw v2, v2, v2
        mtspr 256, r2
        blr

instead of:

_test_rol:
        mfspr r2, 256
        oris r3, r2, 40960
        mtspr 256, r3
        vspltisw v0, -12
        vrlw v2, v0, v0
        mtspr 256, r2
        blr

llvm-svn: 27772
---
 llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp b/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
index 1e80718ebeba..f9cf4142f388 100644
--- a/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
@@ -355,6 +355,22 @@ static void HandleVRSaveUpdate(MachineInstr *MI, const bool *UsedRegs) {
     if (UsedRegs[VRRegNo[i]])
       UsedRegMask |= 1 << (31-i);
   
+  // Live in and live out values already must be in the mask, so don't bother
+  // marking them.
+  MachineFunction *MF = MI->getParent()->getParent();
+  for (MachineFunction::livein_iterator I = 
+       MF->livein_begin(), E = MF->livein_end(); I != E; ++I) {
+    unsigned RegNo = PPCRegisterInfo::getRegisterNumbering(I->first);
+    if (VRRegNo[RegNo] == I->first)        // If this really is a vector reg.
+      UsedRegMask &= ~(1 << (31-RegNo));   // Doesn't need to be marked.
+  }
+  for (MachineFunction::liveout_iterator I = 
+       MF->liveout_begin(), E = MF->liveout_end(); I != E; ++I) {
+    unsigned RegNo = PPCRegisterInfo::getRegisterNumbering(*I);
+    if (VRRegNo[RegNo] == *I)              // If this really is a vector reg.
+      UsedRegMask &= ~(1 << (31-RegNo));   // Doesn't need to be marked.
+  }
+  
   unsigned SrcReg = MI->getOperand(1).getReg();
   unsigned DstReg = MI->getOperand(0).getReg();
   // If no registers are used, turn this into a copy.