Move some of the decision logic for converting an instruction into one that sets
the 'zero' bit down into the back-end. There are other cases where this logic
isn't sufficient, so they should be handled separately.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113665 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/PeepholeOptimizer.cpp b/lib/CodeGen/PeepholeOptimizer.cpp
index a4ff04b..7a1bf40 100644
--- a/lib/CodeGen/PeepholeOptimizer.cpp
+++ b/lib/CodeGen/PeepholeOptimizer.cpp
@@ -240,16 +240,11 @@
unsigned SrcReg;
int CmpValue;
if (!TII->AnalyzeCompare(MI, SrcReg, CmpValue) ||
- TargetRegisterInfo::isPhysicalRegister(SrcReg) || CmpValue != 0)
- return false;
-
- MachineRegisterInfo::def_iterator DI = MRI->def_begin(SrcReg);
- if (llvm::next(DI) != MRI->def_end())
- // Only support one definition.
+ TargetRegisterInfo::isPhysicalRegister(SrcReg))
return false;
// Attempt to convert the defining instruction to set the "zero" flag.
- if (TII->ConvertToSetZeroFlag(&*DI, MI, NextIter)) {
+ if (TII->ConvertToSetZeroFlag(MI, NextIter)) {
++NumEliminated;
return true;
}
diff --git a/lib/Target/ARM/ARMBaseInstrInfo.cpp b/lib/Target/ARM/ARMBaseInstrInfo.cpp
index 142633c..a73e7ad 100644
--- a/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -1377,12 +1377,25 @@
return false;
}
-/// ConvertToSetZeroFlag - Convert the instruction to set the "zero" flag so
-/// that we can remove a "comparison with zero". Update the iterator *only* if a
-/// transformation took place.
+/// ConvertToSetZeroFlag - Convert the instruction supplying the argument to the
+/// comparison into one that sets the zero bit in the flags register. Update the
+/// iterator *only* if a transformation took place.
bool ARMBaseInstrInfo::
-ConvertToSetZeroFlag(MachineInstr *MI, MachineInstr *CmpInstr,
+ConvertToSetZeroFlag(MachineInstr *CmpInstr,
MachineBasicBlock::iterator &MII) const {
+ unsigned SrcReg;
+ int CmpValue;
+ if (!AnalyzeCompare(CmpInstr, SrcReg, CmpValue) || CmpValue != 0)
+ return false;
+
+ MachineRegisterInfo &MRI = CmpInstr->getParent()->getParent()->getRegInfo();
+ MachineRegisterInfo::def_iterator DI = MRI.def_begin(SrcReg);
+ if (llvm::next(DI) != MRI.def_end())
+ // Only support one definition.
+ return false;
+
+ MachineInstr *MI = &*DI;
+
// Conservatively refuse to convert an instruction which isn't in the same BB
// as the comparison.
if (MI->getParent() != CmpInstr->getParent())
diff --git a/lib/Target/ARM/ARMBaseInstrInfo.h b/lib/Target/ARM/ARMBaseInstrInfo.h
index 622402e..2be0d36 100644
--- a/lib/Target/ARM/ARMBaseInstrInfo.h
+++ b/lib/Target/ARM/ARMBaseInstrInfo.h
@@ -346,8 +346,7 @@
/// ConvertToSetZeroFlag - Convert the instruction to set the zero flag so
/// that we can remove a "comparison with zero".
- virtual bool ConvertToSetZeroFlag(MachineInstr *Instr,
- MachineInstr *CmpInstr,
+ virtual bool ConvertToSetZeroFlag(MachineInstr *CmpInstr,
MachineBasicBlock::iterator &MII) const;
virtual unsigned getNumMicroOps(const MachineInstr *MI,