Cleanup initial-value constants in PPCCTRLoops

Because the initial-value constants had not been added to the list
of instructions considered for DCE the resulting code had redundant
constant-materialization instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177294 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel
2013-03-18 17:40:27 +00:00
parent a12c674ee5
commit 1448d06156
2 changed files with 34 additions and 2 deletions

View File

@@ -380,13 +380,13 @@ CountValue *PPCCTRLoops::getTripCount(MachineLoop *L,
assert(InitialValue->isReg() && "Expecting register for init value");
unsigned InitialValueReg = InitialValue->getReg();
const MachineInstr *DefInstr = MRI->getVRegDef(InitialValueReg);
MachineInstr *DefInstr = MRI->getVRegDef(InitialValueReg);
// Here we need to look for an immediate load (an li or lis/ori pair).
if (DefInstr && (DefInstr->getOpcode() == PPC::ORI8 ||
DefInstr->getOpcode() == PPC::ORI)) {
int64_t start = (short) DefInstr->getOperand(2).getImm();
const MachineInstr *DefInstr2 =
MachineInstr *DefInstr2 =
MRI->getVRegDef(DefInstr->getOperand(0).getReg());
if (DefInstr2 && (DefInstr2->getOpcode() == PPC::LIS8 ||
DefInstr2->getOpcode() == PPC::LIS)) {
@@ -399,6 +399,10 @@ CountValue *PPCCTRLoops::getTripCount(MachineLoop *L,
if ((count % iv_value) != 0) {
return 0;
}
OldInsts.push_back(DefInstr);
OldInsts.push_back(DefInstr2);
return new CountValue(count/iv_value);
}
} else if (DefInstr && (DefInstr->getOpcode() == PPC::LI8 ||
@@ -409,6 +413,9 @@ CountValue *PPCCTRLoops::getTripCount(MachineLoop *L,
if ((count % iv_value) != 0) {
return 0;
}
OldInsts.push_back(DefInstr);
return new CountValue(count/iv_value);
} else if (iv_value == 1 || iv_value == -1) {
// We can't determine a constant starting value.