[MachineLICM] Add functions to MachineLICM to hoist invariant stores

This patch adds functions to allow MachineLICM to hoist invariant stores.
Currently, MachineLICM does not hoist any store instructions, however
when storing the same value to a constant spot on the stack, the store
instruction should be considered invariant and be hoisted. The function
isInvariantStore iterates each operand of the store instruction and checks
that each register operand satisfies isCallerPreservedPhysReg. The store
may be fed by a copy, which is hoisted by isCopyFeedingInvariantStore.
This patch also adds the PowerPC changes needed to consider the stack
register as caller preserved.

Differential Revision: https://reviews.llvm.org/D40196

llvm-svn: 327856

1 files changed, 10 insertions, 10 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCMIPeephole.cpp b/llvm/lib/Target/PowerPC/PPCMIPeephole.cpp
index 246770f..8151e43 100644
--- a/llvm/lib/Target/PowerPC/PPCMIPeephole.cpp
+++ b/llvm/lib/Target/PowerPC/PPCMIPeephole.cpp
@@ -220,7 +220,7 @@ bool PPCMIPeephole::simplifyCode(void) {
   bool Simplified = false;
   MachineInstr* ToErase = nullptr;
   std::map<MachineInstr *, bool> TOCSaves;
-
+  const TargetRegisterInfo *TRI = &TII->getRegisterInfo();
   NumFunctionsEnteredInMIPeephole++;
   if (ConvertRegReg) {
     // Fixed-point conversion of reg/reg instructions fed by load-immediate
@@ -297,9 +297,9 @@ bool PPCMIPeephole::simplifyCode(void) {
           // We have to look through chains of COPY and SUBREG_TO_REG
           // to find the real source values for comparison.
           unsigned TrueReg1 =
-            TII->lookThruCopyLike(MI.getOperand(1).getReg(), MRI);
+            TRI->lookThruCopyLike(MI.getOperand(1).getReg(), MRI);
           unsigned TrueReg2 =
-            TII->lookThruCopyLike(MI.getOperand(2).getReg(), MRI);
+            TRI->lookThruCopyLike(MI.getOperand(2).getReg(), MRI);
 
           if (TrueReg1 == TrueReg2
               && TargetRegisterInfo::isVirtualRegister(TrueReg1)) {
@@ -314,7 +314,7 @@ bool PPCMIPeephole::simplifyCode(void) {
               if (DefOpc != PPC::XVCVDPSXDS && DefOpc != PPC::XVCVDPUXDS)
                 return false;
               unsigned DefReg =
-                TII->lookThruCopyLike(DefMI->getOperand(1).getReg(), MRI);
+                TRI->lookThruCopyLike(DefMI->getOperand(1).getReg(), MRI);
               if (TargetRegisterInfo::isVirtualRegister(DefReg)) {
                 MachineInstr *LoadMI = MRI->getVRegDef(DefReg);
                 if (LoadMI && LoadMI->getOpcode() == PPC::LXVDSX)
@@ -341,9 +341,9 @@ bool PPCMIPeephole::simplifyCode(void) {
             if (DefOpc == PPC::XXPERMDI) {
               unsigned FeedImmed = DefMI->getOperand(3).getImm();
               unsigned FeedReg1 =
-                TII->lookThruCopyLike(DefMI->getOperand(1).getReg(), MRI);
+                TRI->lookThruCopyLike(DefMI->getOperand(1).getReg(), MRI);
               unsigned FeedReg2 =
-                TII->lookThruCopyLike(DefMI->getOperand(2).getReg(), MRI);
+                TRI->lookThruCopyLike(DefMI->getOperand(2).getReg(), MRI);
 
               if ((FeedImmed == 0 || FeedImmed == 3) && FeedReg1 == FeedReg2) {
                 DEBUG(dbgs()
@@ -402,7 +402,7 @@ bool PPCMIPeephole::simplifyCode(void) {
         unsigned MyOpcode = MI.getOpcode();
         unsigned OpNo = MyOpcode == PPC::XXSPLTW ? 1 : 2;
         unsigned TrueReg =
-          TII->lookThruCopyLike(MI.getOperand(OpNo).getReg(), MRI);
+          TRI->lookThruCopyLike(MI.getOperand(OpNo).getReg(), MRI);
         if (!TargetRegisterInfo::isVirtualRegister(TrueReg))
           break;
         MachineInstr *DefMI = MRI->getVRegDef(TrueReg);
@@ -465,7 +465,7 @@ bool PPCMIPeephole::simplifyCode(void) {
       case PPC::XVCVDPSP: {
         // If this is a DP->SP conversion fed by an FRSP, the FRSP is redundant.
         unsigned TrueReg =
-          TII->lookThruCopyLike(MI.getOperand(1).getReg(), MRI);
+          TRI->lookThruCopyLike(MI.getOperand(1).getReg(), MRI);
         if (!TargetRegisterInfo::isVirtualRegister(TrueReg))
           break;
         MachineInstr *DefMI = MRI->getVRegDef(TrueReg);
@@ -474,9 +474,9 @@ bool PPCMIPeephole::simplifyCode(void) {
         // values.
         if (DefMI && DefMI->getOpcode() == PPC::XXPERMDI) {
           unsigned DefsReg1 =
-            TII->lookThruCopyLike(DefMI->getOperand(1).getReg(), MRI);
+            TRI->lookThruCopyLike(DefMI->getOperand(1).getReg(), MRI);
           unsigned DefsReg2 =
-            TII->lookThruCopyLike(DefMI->getOperand(2).getReg(), MRI);
+            TRI->lookThruCopyLike(DefMI->getOperand(2).getReg(), MRI);
           if (!TargetRegisterInfo::isVirtualRegister(DefsReg1) ||
               !TargetRegisterInfo::isVirtualRegister(DefsReg2))
             break;