6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-07-22 23:24:59 +00:00
Code Issues Projects Releases Wiki Activity

If fast-isel fails, remove dead instructions generated during the failed

Browse Source 
attempt.  

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145425 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chad Rosier
2011-11-29 19:40:47 +00:00
parent dda8c6ff9e
commit ae6f2cb1fc
3 changed files with 54 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
lib/CodeGen/SelectionDAG/FastISel.cpp
View File

@@ -66,6 +66,7 @@ STATISTIC(NumFastIselSuccessIndependent, "Number of insts selected by "
"target-independent selector");
STATISTIC(NumFastIselSuccessTarget, "Number of insts selected by "
"target-specific selector");
STATISTIC(NumFastIselDead, "Number of dead insts removed on failure");
/// startNewBlock - Set the current block to which generated machine
/// instructions will be appended, and clear the local CSE map.
@@ -309,6 +310,18 @@ void FastISel::recomputeInsertPt() {
++FuncInfo.InsertPt;
}
void FastISel::removeDeadCode(MachineBasicBlock::iterator I,
MachineBasicBlock::iterator E) {
assert (I && E && std::distance(I, E) > 0 && "Invalid iterator!");
while (I != E) {
MachineInstr *Dead = &*I;
++I;
Dead->eraseFromParent();
++NumFastIselDead;
}
recomputeInsertPt();
}
FastISel::SavePoint FastISel::enterLocalValueArea() {
MachineBasicBlock::iterator OldInsertPt = FuncInfo.InsertPt;
DebugLoc OldDL = DL;
@@ -794,19 +807,33 @@ FastISel::SelectInstruction(const Instruction *I) {
DL = I->getDebugLoc();
MachineBasicBlock::iterator SavedInsertPt = FuncInfo.InsertPt;
// First, try doing target-independent selection.
if (SelectOperator(I, I->getOpcode())) {
++NumFastIselSuccessIndependent;
DL = DebugLoc();
return true;
}
// Remove dead code. However, ignore call instructions since we've flushed
// the local value map and recomputed the insert point.
if (!isa<CallInst>(I)) {
recomputeInsertPt();
if (SavedInsertPt != FuncInfo.InsertPt)
removeDeadCode(FuncInfo.InsertPt, SavedInsertPt);
}
// Next, try calling the target to attempt to handle the instruction.
SavedInsertPt = FuncInfo.InsertPt;
if (TargetSelectInstruction(I)) {
++NumFastIselSuccessTarget;
DL = DebugLoc();
return true;
}
// Check for dead code and remove as necessary.
recomputeInsertPt();
if (SavedInsertPt != FuncInfo.InsertPt)
removeDeadCode(FuncInfo.InsertPt, SavedInsertPt);
DL = DebugLoc();
return false;