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-rw-r--r--lib/Target/ARM/ARMFastISel.cpp209
1 files changed, 146 insertions, 63 deletions
diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 5d45f64..a4de941 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -20,6 +20,7 @@
#include "ARMSubtarget.h"
#include "ARMTargetMachine.h"
#include "MCTargetDesc/ARMAddressingModes.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/FastISel.h"
#include "llvm/CodeGen/FunctionLoweringInfo.h"
@@ -41,6 +42,7 @@
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
+#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
@@ -1025,7 +1027,7 @@ bool ARMFastISel::ARMEmitLoad(MVT VT, unsigned &ResultReg, Address &Addr,
useAM3 = true;
}
}
- RC = &ARM::GPRRegClass;
+ RC = isThumb2 ? &ARM::rGPRRegClass : &ARM::GPRnopcRegClass;
break;
case MVT::i16:
if (Alignment && Alignment < 2 && !Subtarget->allowsUnalignedMem())
@@ -1040,7 +1042,7 @@ bool ARMFastISel::ARMEmitLoad(MVT VT, unsigned &ResultReg, Address &Addr,
Opc = isZExt ? ARM::LDRH : ARM::LDRSH;
useAM3 = true;
}
- RC = &ARM::GPRRegClass;
+ RC = isThumb2 ? &ARM::rGPRRegClass : &ARM::GPRnopcRegClass;
break;
case MVT::i32:
if (Alignment && Alignment < 4 && !Subtarget->allowsUnalignedMem())
@@ -1054,7 +1056,7 @@ bool ARMFastISel::ARMEmitLoad(MVT VT, unsigned &ResultReg, Address &Addr,
} else {
Opc = ARM::LDRi12;
}
- RC = &ARM::GPRRegClass;
+ RC = isThumb2 ? &ARM::rGPRRegClass : &ARM::GPRnopcRegClass;
break;
case MVT::f32:
if (!Subtarget->hasVFP2()) return false;
@@ -1063,7 +1065,7 @@ bool ARMFastISel::ARMEmitLoad(MVT VT, unsigned &ResultReg, Address &Addr,
needVMOV = true;
VT = MVT::i32;
Opc = isThumb2 ? ARM::t2LDRi12 : ARM::LDRi12;
- RC = &ARM::GPRRegClass;
+ RC = isThumb2 ? &ARM::rGPRRegClass : &ARM::GPRnopcRegClass;
} else {
Opc = ARM::VLDRS;
RC = TLI.getRegClassFor(VT);
@@ -1802,7 +1804,7 @@ bool ARMFastISel::SelectBinaryIntOp(const Instruction *I, unsigned ISDOpcode) {
unsigned SrcReg2 = getRegForValue(I->getOperand(1));
if (SrcReg2 == 0) return false;
- unsigned ResultReg = createResultReg(TLI.getRegClassFor(MVT::i32));
+ unsigned ResultReg = createResultReg(&ARM::GPRnopcRegClass);
AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
TII.get(Opc), ResultReg)
.addReg(SrcReg1).addReg(SrcReg2));
@@ -1985,7 +1987,7 @@ bool ARMFastISel::ProcessCallArgs(SmallVectorImpl<Value*> &Args,
case CCValAssign::ZExt: {
MVT DestVT = VA.getLocVT();
Arg = ARMEmitIntExt(ArgVT, Arg, DestVT, /*isZExt*/true);
- assert (Arg != 0 && "Failed to emit a sext");
+ assert (Arg != 0 && "Failed to emit a zext");
ArgVT = DestVT;
break;
}
@@ -2602,47 +2604,112 @@ unsigned ARMFastISel::ARMEmitIntExt(MVT SrcVT, unsigned SrcReg, MVT DestVT,
bool isZExt) {
if (DestVT != MVT::i32 && DestVT != MVT::i16 && DestVT != MVT::i8)
return 0;
+ if (SrcVT != MVT::i16 && SrcVT != MVT::i8 && SrcVT != MVT::i1)
+ return 0;
- unsigned Opc;
- bool isBoolZext = false;
- const TargetRegisterClass *RC;
- switch (SrcVT.SimpleTy) {
- default: return 0;
- case MVT::i16:
- if (!Subtarget->hasV6Ops()) return 0;
- RC = isThumb2 ? &ARM::rGPRRegClass : &ARM::GPRnopcRegClass;
- if (isZExt)
- Opc = isThumb2 ? ARM::t2UXTH : ARM::UXTH;
- else
- Opc = isThumb2 ? ARM::t2SXTH : ARM::SXTH;
- break;
- case MVT::i8:
- if (!Subtarget->hasV6Ops()) return 0;
- RC = isThumb2 ? &ARM::rGPRRegClass : &ARM::GPRnopcRegClass;
- if (isZExt)
- Opc = isThumb2 ? ARM::t2UXTB : ARM::UXTB;
- else
- Opc = isThumb2 ? ARM::t2SXTB : ARM::SXTB;
- break;
- case MVT::i1:
- if (isZExt) {
- RC = isThumb2 ? &ARM::rGPRRegClass : &ARM::GPRRegClass;
- Opc = isThumb2 ? ARM::t2ANDri : ARM::ANDri;
- isBoolZext = true;
- break;
+ // Table of which combinations can be emitted as a single instruction,
+ // and which will require two.
+ static const uint8_t isSingleInstrTbl[3][2][2][2] = {
+ // ARM Thumb
+ // !hasV6Ops hasV6Ops !hasV6Ops hasV6Ops
+ // ext: s z s z s z s z
+ /* 1 */ { { { 0, 1 }, { 0, 1 } }, { { 0, 0 }, { 0, 1 } } },
+ /* 8 */ { { { 0, 1 }, { 1, 1 } }, { { 0, 0 }, { 1, 1 } } },
+ /* 16 */ { { { 0, 0 }, { 1, 1 } }, { { 0, 0 }, { 1, 1 } } }
+ };
+
+ // Target registers for:
+ // - For ARM can never be PC.
+ // - For 16-bit Thumb are restricted to lower 8 registers.
+ // - For 32-bit Thumb are restricted to non-SP and non-PC.
+ static const TargetRegisterClass *RCTbl[2][2] = {
+ // Instructions: Two Single
+ /* ARM */ { &ARM::GPRnopcRegClass, &ARM::GPRnopcRegClass },
+ /* Thumb */ { &ARM::tGPRRegClass, &ARM::rGPRRegClass }
+ };
+
+ // Table governing the instruction(s) to be emitted.
+ static const struct {
+ // First entry for each of the following is sext, second zext.
+ uint16_t Opc[2];
+ uint8_t Imm[2]; // All instructions have either a shift or a mask.
+ uint8_t hasS[2]; // Some instructions have an S bit, always set it to 0.
+ } OpcTbl[2][2][3] = {
+ { // Two instructions (first is left shift, second is in this table).
+ { // ARM
+ /* 1 */ { { ARM::ASRi, ARM::LSRi }, { 31, 31 }, { 1, 1 } },
+ /* 8 */ { { ARM::ASRi, ARM::LSRi }, { 24, 24 }, { 1, 1 } },
+ /* 16 */ { { ARM::ASRi, ARM::LSRi }, { 16, 16 }, { 1, 1 } }
+ },
+ { // Thumb
+ /* 1 */ { { ARM::tASRri, ARM::tLSRri }, { 31, 31 }, { 0, 0 } },
+ /* 8 */ { { ARM::tASRri, ARM::tLSRri }, { 24, 24 }, { 0, 0 } },
+ /* 16 */ { { ARM::tASRri, ARM::tLSRri }, { 16, 16 }, { 0, 0 } }
+ }
+ },
+ { // Single instruction.
+ { // ARM
+ /* 1 */ { { ARM::KILL, ARM::ANDri }, { 0, 1 }, { 0, 1 } },
+ /* 8 */ { { ARM::SXTB, ARM::ANDri }, { 0, 255 }, { 0, 1 } },
+ /* 16 */ { { ARM::SXTH, ARM::UXTH }, { 0, 0 }, { 0, 0 } }
+ },
+ { // Thumb
+ /* 1 */ { { ARM::KILL, ARM::t2ANDri }, { 0, 1 }, { 0, 1 } },
+ /* 8 */ { { ARM::t2SXTB, ARM::t2ANDri }, { 0, 255 }, { 0, 1 } },
+ /* 16 */ { { ARM::t2SXTH, ARM::t2UXTH }, { 0, 0 }, { 0, 0 } }
+ }
}
- return 0;
+ };
+
+ unsigned SrcBits = SrcVT.getSizeInBits();
+ unsigned DestBits = DestVT.getSizeInBits();
+ (void) DestBits;
+ assert((SrcBits < DestBits) && "can only extend to larger types");
+ assert((DestBits == 32 || DestBits == 16 || DestBits == 8) &&
+ "other sizes unimplemented");
+ assert((SrcBits == 16 || SrcBits == 8 || SrcBits == 1) &&
+ "other sizes unimplemented");
+
+ bool hasV6Ops = Subtarget->hasV6Ops();
+ unsigned Bitness = countTrailingZeros(SrcBits) >> 1; // {1,8,16}=>{0,1,2}
+ assert((Bitness < 3) && "sanity-check table bounds");
+
+ bool isSingleInstr = isSingleInstrTbl[Bitness][isThumb2][hasV6Ops][isZExt];
+ const TargetRegisterClass *RC = RCTbl[isThumb2][isSingleInstr];
+ unsigned Opc = OpcTbl[isSingleInstr][isThumb2][Bitness].Opc[isZExt];
+ assert(ARM::KILL != Opc && "Invalid table entry");
+ unsigned Imm = OpcTbl[isSingleInstr][isThumb2][Bitness].Imm[isZExt];
+ unsigned hasS = OpcTbl[isSingleInstr][isThumb2][Bitness].hasS[isZExt];
+
+ // 16-bit Thumb instructions always set CPSR (unless they're in an IT block).
+ bool setsCPSR = &ARM::tGPRRegClass == RC;
+ unsigned LSLOpc = isThumb2 ? ARM::tLSLri : ARM::LSLi;
+ unsigned ResultReg;
+
+ // Either one or two instructions are emitted.
+ // They're always of the form:
+ // dst = in OP imm
+ // CPSR is set only by 16-bit Thumb instructions.
+ // Predicate, if any, is AL.
+ // S bit, if available, is always 0.
+ // When two are emitted the first's result will feed as the second's input,
+ // that value is then dead.
+ unsigned NumInstrsEmitted = isSingleInstr ? 1 : 2;
+ for (unsigned Instr = 0; Instr != NumInstrsEmitted; ++Instr) {
+ ResultReg = createResultReg(RC);
+ unsigned Opcode = ((0 == Instr) && !isSingleInstr) ? LSLOpc : Opc;
+ bool isKill = 1 == Instr;
+ MachineInstrBuilder MIB = BuildMI(
+ *FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(Opcode), ResultReg);
+ if (setsCPSR)
+ MIB.addReg(ARM::CPSR, RegState::Define);
+ AddDefaultPred(MIB.addReg(SrcReg, isKill * RegState::Kill).addImm(Imm));
+ if (hasS)
+ AddDefaultCC(MIB);
+ // Second instruction consumes the first's result.
+ SrcReg = ResultReg;
}
- unsigned ResultReg = createResultReg(RC);
- MachineInstrBuilder MIB;
- MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(Opc), ResultReg)
- .addReg(SrcReg);
- if (isBoolZext)
- MIB.addImm(1);
- else
- MIB.addImm(0);
- AddOptionalDefs(MIB);
return ResultReg;
}
@@ -2707,7 +2774,7 @@ bool ARMFastISel::SelectShift(const Instruction *I,
if (Reg2 == 0) return false;
}
- unsigned ResultReg = createResultReg(TLI.getRegClassFor(MVT::i32));
+ unsigned ResultReg = createResultReg(&ARM::GPRnopcRegClass);
if(ResultReg == 0) return false;
MachineInstrBuilder MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
@@ -2797,6 +2864,25 @@ bool ARMFastISel::TargetSelectInstruction(const Instruction *I) {
return false;
}
+namespace {
+// This table describes sign- and zero-extend instructions which can be
+// folded into a preceding load. All of these extends have an immediate
+// (sometimes a mask and sometimes a shift) that's applied after
+// extension.
+const struct FoldableLoadExtendsStruct {
+ uint16_t Opc[2]; // ARM, Thumb.
+ uint8_t ExpectedImm;
+ uint8_t isZExt : 1;
+ uint8_t ExpectedVT : 7;
+} FoldableLoadExtends[] = {
+ { { ARM::SXTH, ARM::t2SXTH }, 0, 0, MVT::i16 },
+ { { ARM::UXTH, ARM::t2UXTH }, 0, 1, MVT::i16 },
+ { { ARM::ANDri, ARM::t2ANDri }, 255, 1, MVT::i8 },
+ { { ARM::SXTB, ARM::t2SXTB }, 0, 0, MVT::i8 },
+ { { ARM::UXTB, ARM::t2UXTB }, 0, 1, MVT::i8 }
+};
+}
+
/// \brief The specified machine instr operand is a vreg, and that
/// vreg is being provided by the specified load instruction. If possible,
/// try to fold the load as an operand to the instruction, returning true if
@@ -2812,26 +2898,23 @@ bool ARMFastISel::tryToFoldLoadIntoMI(MachineInstr *MI, unsigned OpNo,
// ldrb r1, [r0] ldrb r1, [r0]
// uxtb r2, r1 =>
// mov r3, r2 mov r3, r1
- bool isZExt = true;
- switch(MI->getOpcode()) {
- default: return false;
- case ARM::SXTH:
- case ARM::t2SXTH:
- isZExt = false;
- case ARM::UXTH:
- case ARM::t2UXTH:
- if (VT != MVT::i16)
- return false;
- break;
- case ARM::SXTB:
- case ARM::t2SXTB:
- isZExt = false;
- case ARM::UXTB:
- case ARM::t2UXTB:
- if (VT != MVT::i8)
- return false;
- break;
+ if (MI->getNumOperands() < 3 || !MI->getOperand(2).isImm())
+ return false;
+ const uint64_t Imm = MI->getOperand(2).getImm();
+
+ bool Found = false;
+ bool isZExt;
+ for (unsigned i = 0, e = array_lengthof(FoldableLoadExtends);
+ i != e; ++i) {
+ if (FoldableLoadExtends[i].Opc[isThumb2] == MI->getOpcode() &&
+ (uint64_t)FoldableLoadExtends[i].ExpectedImm == Imm &&
+ MVT((MVT::SimpleValueType)FoldableLoadExtends[i].ExpectedVT) == VT) {
+ Found = true;
+ isZExt = FoldableLoadExtends[i].isZExt;
+ }
}
+ if (!Found) return false;
+
// See if we can handle this address.
Address Addr;
if (!ARMComputeAddress(LI->getOperand(0), Addr)) return false;
generated by cgit v1.1 at 2025-08-18 02:36:38 +0000