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[lanai] Change the way flag setting instructions are checked. 

isReturn() was returning different values with and without -g which led to
different code being generated. Change isFlagSettingInstruction to query
an instruction's effect on SR instead.

llvm-svn: 269986
This commit is contained in:
Jacques Pienaar 2016-05-18 21:31:37 +00:00
parent d2268a73bc
commit 314444b4cd
1 changed files with 11 additions and 51 deletions
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62
llvm/lib/Target/Lanai/LanaiSetflagAluCombiner.cpp
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@ -142,47 +142,8 @@ static unsigned flagSettingOpcodeVariant(unsigned OldOpcode) {
}
// Returns whether opcode corresponds to instruction that sets flags.
static bool isFlagSettingInstruction(unsigned Opcode) {
switch (Opcode) {
case Lanai::ADDC_F_I_HI:
case Lanai::ADDC_F_I_LO:
case Lanai::ADDC_F_R:
case Lanai::ADDC_F_R_CC:
case Lanai::ADD_F_I_HI:
case Lanai::ADD_F_I_LO:
case Lanai::ADD_F_R:
case Lanai::ADD_F_R_CC:
case Lanai::AND_F_I_HI:
case Lanai::AND_F_I_LO:
case Lanai::AND_F_R:
case Lanai::AND_F_R_CC:
case Lanai::OR_F_I_HI:
case Lanai::OR_F_I_LO:
case Lanai::OR_F_R:
case Lanai::OR_F_R_CC:
case Lanai::SFSUB_F_RI:
case Lanai::SFSUB_F_RR:
case Lanai::SA_F_I:
case Lanai::SL_F_I:
case Lanai::SHL_F_R:
case Lanai::SRA_F_R:
case Lanai::SRL_F_R:
case Lanai::SUBB_F_I_HI:
case Lanai::SUBB_F_I_LO:
case Lanai::SUBB_F_R:
case Lanai::SUBB_F_R_CC:
case Lanai::SUB_F_I_HI:
case Lanai::SUB_F_I_LO:
case Lanai::SUB_F_R:
case Lanai::SUB_F_R_CC:
case Lanai::XOR_F_I_HI:
case Lanai::XOR_F_I_LO:
case Lanai::XOR_F_R:
case Lanai::XOR_F_R_CC:
return true;
default:
return false;
}
static bool isFlagSettingInstruction(MbbIterator Instruction) {
return Instruction->killsRegister(Lanai::SR);
}
// Return the Conditional Code operand for a given instruction kind. For
@ -233,9 +194,13 @@ static bool isSuitableSetflag(MbbIterator Instruction, MbbIterator End) {
MbbIterator SCCUserIter = Instruction;
while (SCCUserIter != End) {
++SCCUserIter;
if (SCCUserIter == End)
break;
// Skip debug instructions. Debug instructions don't affect codegen.
if (SCCUserIter->isDebugValue())
continue;
// Early exit when encountering flag setting or return instruction.
if (isFlagSettingInstruction(SCCUserIter->getOpcode()) ||
SCCUserIter->isReturn())
if (isFlagSettingInstruction(SCCUserIter))
// Only return true if flags are set post the flag setting instruction
// tested or a return is executed.
return true;
@ -274,13 +239,11 @@ bool LanaiSetflagAluCombiner::CombineSetflagAluInBasicBlock(
while (AluIter != Begin) {
--AluIter;
// Skip debug instructions. Debug instructions don't affect codegen.
if (AluIter->isDebugValue()) {
if (AluIter->isDebugValue())
continue;
}
// Early exit when encountering flag setting instruction.
if (isFlagSettingInstruction(AluIter->getOpcode())) {
if (isFlagSettingInstruction(AluIter))
break;
}
// Check that output of AluIter is equal to input of SetflagIter.
if (AluIter->getNumOperands() > 1 && AluIter->getOperand(0).isReg() &&
(AluIter->getOperand(0).getReg() ==
@ -299,14 +262,11 @@ bool LanaiSetflagAluCombiner::CombineSetflagAluInBasicBlock(
}
}
// Erase the setflag instruction if merged.
if (Replaced) {
if (Replaced)
BB->erase(SetflagIter++);
}
}
Modified |= Replaced;
if (SetflagIter == End)
break;
if (!Replaced)
++SetflagIter;
}