From 8a88cadaedcfa3bb020df1d100d67cecaf638f35 Mon Sep 17 00:00:00 2001 From: Hal Finkel Date: Tue, 7 May 2013 17:49:55 +0000 Subject: [PATCH] Cleanup PPCInstrInfo::optimizeCompareInstr Implement suggestions by Bill Schmidt in post-commit review. No functionality change intended. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181338 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/PowerPC/PPCInstrInfo.cpp | 24 ++++++++++-------------- 1 file changed, 10 insertions(+), 14 deletions(-) diff --git a/lib/Target/PowerPC/PPCInstrInfo.cpp b/lib/Target/PowerPC/PPCInstrInfo.cpp index 847bd224b6f..e6dac83e849 100644 --- a/lib/Target/PowerPC/PPCInstrInfo.cpp +++ b/lib/Target/PowerPC/PPCInstrInfo.cpp @@ -1153,25 +1153,19 @@ bool PPCInstrInfo::optimizeCompareInstr(MachineInstr *CmpInstr, MachineInstr *UseMI = &*I; if (UseMI->getOpcode() == PPC::BCC) { unsigned Pred = UseMI->getOperand(0).getImm(); - if (Pred == PPC::PRED_EQ || Pred == PPC::PRED_NE) - continue; - - return false; + if (Pred != PPC::PRED_EQ && Pred != PPC::PRED_NE) + return false; } else if (UseMI->getOpcode() == PPC::ISEL || UseMI->getOpcode() == PPC::ISEL8) { unsigned SubIdx = UseMI->getOperand(3).getSubReg(); - if (SubIdx == PPC::sub_eq) - continue; - - return false; + if (SubIdx != PPC::sub_eq) + return false; } else return false; } } - // Get ready to iterate backward from CmpInstr. - MachineBasicBlock::iterator I = CmpInstr, E = MI, - B = CmpInstr->getParent()->begin(); + MachineBasicBlock::iterator I = CmpInstr; // Scan forward to find the first use of the compare. for (MachineBasicBlock::iterator EL = CmpInstr->getParent()->end(); @@ -1188,9 +1182,6 @@ bool PPCInstrInfo::optimizeCompareInstr(MachineInstr *CmpInstr, break; } - // Early exit if we're at the beginning of the BB. - if (I == B) return false; - // There are two possible candidates which can be changed to set CR[01]. // One is MI, the other is a SUB instruction. // For CMPrr(r1,r2), we are looking for SUB(r1,r2) or SUB(r2,r1). @@ -1210,6 +1201,11 @@ bool PPCInstrInfo::optimizeCompareInstr(MachineInstr *CmpInstr, // Search for Sub. const TargetRegisterInfo *TRI = &getRegisterInfo(); --I; + + // Get ready to iterate backward from CmpInstr. + MachineBasicBlock::iterator E = MI, + B = CmpInstr->getParent()->begin(); + for (; I != E && !noSub; --I) { const MachineInstr &Instr = *I; unsigned IOpC = Instr.getOpcode(); -- 2.34.1