diff options
| author | 2015-11-20 15:08:11 +0000 | |
|---|---|---|
| committer | 2015-11-20 16:18:39 +0000 | |
| commit | f9d741e32c6f1629ce70eefc68d3363fa1cfd696 (patch) | |
| tree | 409005e5b1d01d2830c20421f8466125e110d6af /compiler/optimizing | |
| parent | beb709a2607a00b5df33f0235f22ccdd876cee22 (diff) | |
Optimizing/ARM: Improve long shifts by 1.
Implement long
Shl(x,1) as LSLS+ADC,
Shr(x,1) as ASR+RRX and
UShr(x,1) as LSR+RRX.
Remove the simplification substituting Shl(x,1) with
ADD(x,x) as it interferes with some other optimizations
instead of helping them. And since it didn't help 64-bit
architectures anyway, codegen is the correct place for it.
This is now implemented for ARM and x86, so only mips32 can
be improved.
Change-Id: Idd14f23292198b2260189e1497ca5411b21743b3
Diffstat (limited to 'compiler/optimizing')
| -rw-r--r-- | compiler/optimizing/code_generator_arm.cc | 14 | ||||
| -rw-r--r-- | compiler/optimizing/instruction_simplifier.cc | 10 |
2 files changed, 13 insertions, 11 deletions
diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc index 12ab68e8cd..c7e412c8e3 100644 --- a/compiler/optimizing/code_generator_arm.cc +++ b/compiler/optimizing/code_generator_arm.cc @@ -3361,7 +3361,19 @@ void InstructionCodeGeneratorARM::HandleShift(HBinaryOperation* op) { __ mov(o_l, ShifterOperand(high)); __ LoadImmediate(o_h, 0); } - } else { // shift_value < 32 + } else if (shift_value == 1) { + if (op->IsShl()) { + __ Lsls(o_l, low, 1); + __ adc(o_h, high, ShifterOperand(high)); + } else if (op->IsShr()) { + __ Asrs(o_h, high, 1); + __ Rrx(o_l, low); + } else { + __ Lsrs(o_h, high, 1); + __ Rrx(o_l, low); + } + } else { + DCHECK(2 <= shift_value && shift_value < 32) << shift_value; if (op->IsShl()) { __ Lsl(o_h, high, shift_value); __ orr(o_h, o_h, ShifterOperand(low, LSR, 32 - shift_value)); diff --git a/compiler/optimizing/instruction_simplifier.cc b/compiler/optimizing/instruction_simplifier.cc index b97dc1a511..b36870cf59 100644 --- a/compiler/optimizing/instruction_simplifier.cc +++ b/compiler/optimizing/instruction_simplifier.cc @@ -169,16 +169,6 @@ void InstructionSimplifierVisitor::VisitShift(HBinaryOperation* instruction) { // src instruction->ReplaceWith(input_other); instruction->GetBlock()->RemoveInstruction(instruction); - } else if (instruction->IsShl() && input_cst->IsOne()) { - // Replace Shl looking like - // SHL dst, src, 1 - // with - // ADD dst, src, src - HAdd *add = new(GetGraph()->GetArena()) HAdd(instruction->GetType(), - input_other, - input_other); - instruction->GetBlock()->ReplaceAndRemoveInstructionWith(instruction, add); - RecordSimplification(); } } } |