Don't emit FP_REG_KILL into a block that just returns. Nothing
can be live out of the block anyway, so it isn't needed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48192 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index 6036dcb..a4da541 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -550,7 +550,8 @@
DAG.RemoveDeadNodes();
- // Emit machine code to BB.
+ // Emit machine code to BB. This can change 'BB' to the last block being
+ // inserted into.
ScheduleAndEmitDAG(DAG);
// If we are emitting FP stack code, scan the basic block to determine if this
@@ -566,15 +567,27 @@
// Scan all of the machine instructions in these MBBs, checking for FP
// stores. (RFP32 and RFP64 will not exist in SSE mode, but RFP80 might.)
MachineFunction::iterator MBBI = FirstMBB;
- do {
+ MachineFunction::iterator EndMBB = BB; ++EndMBB;
+ for (; MBBI != EndMBB; ++MBBI) {
+ MachineBasicBlock *MBB = MBBI;
+
+ // If this block returns, ignore it. We don't want to insert an FP_REG_KILL
+ // before the return.
+ if (!MBB->empty()) {
+ MachineBasicBlock::iterator EndI = MBB->end();
+ --EndI;
+ if (EndI->getDesc().isReturn())
+ continue;
+ }
+
bool ContainsFPCode = false;
- for (MachineBasicBlock::iterator I = MBBI->begin(), E = MBBI->end();
+ for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
!ContainsFPCode && I != E; ++I) {
if (I->getNumOperands() != 0 && I->getOperand(0).isRegister()) {
const TargetRegisterClass *clas;
for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op) {
if (I->getOperand(op).isRegister() && I->getOperand(op).isDef() &&
- TargetRegisterInfo::isVirtualRegister(I->getOperand(op).getReg()) &&
+ TargetRegisterInfo::isVirtualRegister(I->getOperand(op).getReg()) &&
((clas = RegInfo->getRegClass(I->getOperand(0).getReg())) ==
X86::RFP32RegisterClass ||
clas == X86::RFP64RegisterClass ||
@@ -608,11 +621,11 @@
}
// Finally, if we found any FP code, emit the FP_REG_KILL instruction.
if (ContainsFPCode) {
- BuildMI(*MBBI, MBBI->getFirstTerminator(),
+ BuildMI(*MBB, MBBI->getFirstTerminator(),
TM.getInstrInfo()->get(X86::FP_REG_KILL));
++NumFPKill;
}
- } while (&*(MBBI++) != BB);
+ }
}
/// EmitSpecialCodeForMain - Emit any code that needs to be executed only in