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[ARM] Refactor converting Thumb1 from 3 to 2 operand (nfc) 

Also adds some test cases.

Differential Revision: http://reviews.llvm.org/D11054

llvm-svn: 241799
This commit is contained in:
Scott Douglass 2015-07-09 14:13:34 +00:00
parent 5d3075a6bf
commit 8c7803f4c1
2 changed files with 64 additions and 42 deletions
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87
llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
View File

@ -242,6 +242,8 @@ class ARMAsmParser : public MCTargetAsmParser {
bool &CanAcceptCarrySet,
bool &CanAcceptPredicationCode);
void tryConvertingToTwoOperandForm(StringRef Mnemonic, bool CarrySetting,
OperandVector &Operands);
bool isThumb() const {
// FIXME: Can tablegen auto-generate this?
return STI.getFeatureBits()[ARM::ModeThumb];
@ -5465,6 +5467,47 @@ void ARMAsmParser::getMnemonicAcceptInfo(StringRef Mnemonic, StringRef FullInst,
CanAcceptPredicationCode = true;
}
// \brief Some Thumb1 instructions have two operand forms that are not
// available as three operand, convert to two operand form if possible.
//
// FIXME: We would really like to be able to tablegen'erate this.
void ARMAsmParser::tryConvertingToTwoOperandForm(StringRef Mnemonic,
bool CarrySetting,
OperandVector &Operands) {
if (Operands.size() != 6 || !isThumbOne())
return;
ARMOperand &Op3 = static_cast<ARMOperand &>(*Operands[3]);
ARMOperand &Op4 = static_cast<ARMOperand &>(*Operands[4]);
if (!Op3.isReg() || !Op4.isReg())
return;
ARMOperand &Op5 = static_cast<ARMOperand &>(*Operands[5]);
if (!(Mnemonic == "add" || Mnemonic == "sub" || Mnemonic == "and" ||
Mnemonic == "eor" || Mnemonic == "lsl" || Mnemonic == "lsr" ||
Mnemonic == "asr" || Mnemonic == "adc" || Mnemonic == "sbc" ||
Mnemonic == "ror" || Mnemonic == "orr" || Mnemonic == "bic"))
return;
// If first 2 operands of a 3 operand instruction are the same
// then transform to 2 operand version of the same instruction
// e.g. 'adds r0, r0, #1' transforms to 'adds r0, #1'
bool Transform = Op3.getReg() == Op4.getReg();
// If both registers are the same then remove one of them from
// the operand list, with certain exceptions.
if (Transform) {
// Don't transform 'adds Rd, Rd, Rm' or 'sub{s} Rd, Rd, Rm' because the
// 2 operand forms don't exist.
if (((Mnemonic == "add" && CarrySetting) || Mnemonic == "sub") &&
Op5.isReg())
Transform = false;
}
if (Transform)
Operands.erase(Operands.begin() + 3);
}
bool ARMAsmParser::shouldOmitCCOutOperand(StringRef Mnemonic,
OperandVector &Operands) {
// FIXME: This is all horribly hacky. We really need a better way to deal
@ -5838,6 +5881,8 @@ bool ARMAsmParser::ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
"VFP/Neon double precision register expected");
}
tryConvertingToTwoOperandForm(Mnemonic, CarrySetting, Operands);
// Some instructions, mostly Thumb, have forms for the same mnemonic that
// do and don't have a cc_out optional-def operand. With some spot-checks
// of the operand list, we can figure out which variant we're trying to
@ -5901,48 +5946,6 @@ bool ARMAsmParser::ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
}
}
// If first 2 operands of a 3 operand instruction are the same
// then transform to 2 operand version of the same instruction
// e.g. 'adds r0, r0, #1' transforms to 'adds r0, #1'
// FIXME: We would really like to be able to tablegen'erate this.
if (isThumbOne() && Operands.size() == 6 &&
(Mnemonic == "add" || Mnemonic == "sub" || Mnemonic == "and" ||
Mnemonic == "eor" || Mnemonic == "lsl" || Mnemonic == "lsr" ||
Mnemonic == "asr" || Mnemonic == "adc" || Mnemonic == "sbc" ||
Mnemonic == "ror" || Mnemonic == "orr" || Mnemonic == "bic")) {
ARMOperand &Op3 = static_cast<ARMOperand &>(*Operands[3]);
ARMOperand &Op4 = static_cast<ARMOperand &>(*Operands[4]);
ARMOperand &Op5 = static_cast<ARMOperand &>(*Operands[5]);
// If both registers are the same then remove one of them from
// the operand list.
if (Op3.isReg() && Op4.isReg() && Op3.getReg() == Op4.getReg()) {
// If 3rd operand (variable Op5) is a register and the instruction is adds/sub
// then do not transform as the backend already handles this instruction
// correctly.
if (!Op5.isReg() || !((Mnemonic == "add" && CarrySetting) || Mnemonic == "sub")) {
Operands.erase(Operands.begin() + 3);
if (Mnemonic == "add" && !CarrySetting) {
// Special case for 'add' (not 'adds') instruction must
// remove the CCOut operand as well.
Operands.erase(Operands.begin() + 1);
}
}
}
}
// If instruction is 'add' and first two register operands
// use SP register, then remove one of the SP registers from
// the instruction.
// FIXME: We would really like to be able to tablegen'erate this.
if (isThumbOne() && Operands.size() == 5 && Mnemonic == "add" && !CarrySetting) {
ARMOperand &Op2 = static_cast<ARMOperand &>(*Operands[2]);
ARMOperand &Op3 = static_cast<ARMOperand &>(*Operands[3]);
if (Op2.isReg() && Op3.isReg() && Op2.getReg() == ARM::SP && Op3.getReg() == ARM::SP) {
Operands.erase(Operands.begin() + 2);
}
}
// GNU Assembler extension (compatibility)
if ((Mnemonic == "ldrd" || Mnemonic == "strd")) {
ARMOperand &Op2 = static_cast<ARMOperand &>(*Operands[2]);

19
llvm/test/MC/ARM/thumb_rewrites.s
View File

@ -12,6 +12,19 @@
add sp, sp, r0
@ CHECK: add sp, r0 @ encoding: [0x85,0x44]
add r4, sp, r4
@ CHECK: add r4, sp, r4 @ encoding: [0x6c,0x44]
add r4, r4, sp
@ CHECK: add r4, sp @ encoding: [0x6c,0x44]
add sp, sp, #32
@ FIXME: ARMARM says 'add sp, sp, #32'
@ CHECK: add sp, #32 @ encoding: [0x08,0xb0]
add r5, sp, #1016
@ CHECK: add r5, sp, #1016 @ encoding: [0xfe,0xad]
add r0, r0, r1
@ CHECK: add r0, r1 @ encoding: [0x08,0x44]
@ -21,6 +34,12 @@
subs r0, r0, r0
@ CHECK: subs r0, r0, r0 @ encoding: [0x00,0x1a]
subs r2, r2, #8
@ CHECK: subs r2, #8 @ encoding: [0x08,0x3a]
sub sp, sp, #16
@ CHECK: sub sp, #16 @ encoding: [0x84,0xb0]
ands r0, r0, r1
@ CHECK: ands r0, r1 @ encoding: [0x08,0x40]