Change ARM PKHTB and PKHBT instructions to use a shift_imm operand to avoid

printing "lsl #0".  This fixes the remaining parts of pr7792.  Make
corresponding changes for encoding/decoding these instructions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111251 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 69 insertions, 39 deletions

diff --git a/lib/Target/ARM/ARMCodeEmitter.cpp b/lib/Target/ARM/ARMCodeEmitter.cpp
index 5ccba1cedb..0d9b1a1e65 100644
--- a/lib/Target/ARM/ARMCodeEmitter.cpp
+++ b/lib/Target/ARM/ARMCodeEmitter.cpp
@@ -1227,6 +1227,11 @@ void ARMCodeEmitter::emitMiscArithInstruction(const MachineInstr &MI) {
 
   // Encode shift_imm.
   unsigned ShiftAmt = MI.getOperand(OpIdx).getImm();
+  if (TID.Opcode == ARM::PKHTB) {
+    assert(ShiftAmt != 0 && "PKHTB shift_imm is 0!");
+    if (ShiftAmt == 32)
+      ShiftAmt = 0;
+  }
   assert(ShiftAmt < 32 && "shift_imm range is 0 to 31!");
   Binary |= ShiftAmt << ARMII::ShiftShift;
 
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 09ce5528c5..c0724f5064 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -2240,11 +2240,20 @@ def REVSH : AMiscA1I<0b01101111, (outs GPR:$dst), (ins GPR:$src), IIC_iUNAr,
   let Inst{19-16} = 0b1111;
 }
 
+def lsl_shift_imm : SDNodeXForm<imm, [{
+  unsigned Sh = ARM_AM::getSORegOpc(ARM_AM::lsl, N->getZExtValue());
+  return CurDAG->getTargetConstant(Sh, MVT::i32);
+}]>;
+
+def lsl_amt : PatLeaf<(i32 imm), [{
+  return (N->getZExtValue() < 32);
+}], lsl_shift_imm>;
+
 def PKHBT : AMiscA1I<0b01101000, (outs GPR:$dst),
-                                 (ins GPR:$src1, GPR:$src2, i32imm:$shamt),
-               IIC_iALUsi, "pkhbt", "\t$dst, $src1, $src2, lsl $shamt",
+                                 (ins GPR:$src1, GPR:$src2, shift_imm:$sh),
+               IIC_iALUsi, "pkhbt", "\t$dst, $src1, $src2$sh",
                [(set GPR:$dst, (or (and GPR:$src1, 0xFFFF),
-                                   (and (shl GPR:$src2, (i32 imm:$shamt)),
+                                   (and (shl GPR:$src2, lsl_amt:$sh),
                                         0xFFFF0000)))]>,
                Requires<[IsARM, HasV6]> {
   let Inst{6-4} = 0b001;
@@ -2253,28 +2262,37 @@ def PKHBT : AMiscA1I<0b01101000, (outs GPR:$dst),
 // Alternate cases for PKHBT where identities eliminate some nodes.
 def : ARMV6Pat<(or (and GPR:$src1, 0xFFFF), (and GPR:$src2, 0xFFFF0000)),
                (PKHBT GPR:$src1, GPR:$src2, 0)>;
-def : ARMV6Pat<(or (and GPR:$src1, 0xFFFF), (shl GPR:$src2, imm16_31:$shamt)),
-               (PKHBT GPR:$src1, GPR:$src2, imm16_31:$shamt)>;
+def : ARMV6Pat<(or (and GPR:$src1, 0xFFFF), (shl GPR:$src2, imm16_31:$sh)),
+               (PKHBT GPR:$src1, GPR:$src2, (lsl_shift_imm imm16_31:$sh))>;
 
+def asr_shift_imm : SDNodeXForm<imm, [{
+  unsigned Sh = ARM_AM::getSORegOpc(ARM_AM::asr, N->getZExtValue());
+  return CurDAG->getTargetConstant(Sh, MVT::i32);
+}]>;
+
+def asr_amt : PatLeaf<(i32 imm), [{
+  return (N->getZExtValue() <= 32);
+}], asr_shift_imm>;
 
 // Note: Shifts of 1-15 bits will be transformed to srl instead of sra and
 // will match the pattern below.
 def PKHTB : AMiscA1I<0b01101000, (outs GPR:$dst),
-                                 (ins GPR:$src1, GPR:$src2, i32imm:$shamt),
-               IIC_iALUsi, "pkhtb", "\t$dst, $src1, $src2, asr $shamt",
+                                 (ins GPR:$src1, GPR:$src2, shift_imm:$sh),
+               IIC_iALUsi, "pkhtb", "\t$dst, $src1, $src2$sh",
                [(set GPR:$dst, (or (and GPR:$src1, 0xFFFF0000),
-                                   (and (sra GPR:$src2, imm16_31:$shamt),
-                                        0xFFFF)))]>, Requires<[IsARM, HasV6]> {
+                                   (and (sra GPR:$src2, asr_amt:$sh),
+                                        0xFFFF)))]>,
+               Requires<[IsARM, HasV6]> {
   let Inst{6-4} = 0b101;
 }
 
 // Alternate cases for PKHTB where identities eliminate some nodes.  Note that
 // a shift amount of 0 is *not legal* here, it is PKHBT instead.
 def : ARMV6Pat<(or (and GPR:$src1, 0xFFFF0000), (srl GPR:$src2, imm16_31:$sh)),
-               (PKHTB GPR:$src1, GPR:$src2, imm16_31:$sh)>;
+               (PKHTB GPR:$src1, GPR:$src2, (asr_shift_imm imm16_31:$sh))>;
 def : ARMV6Pat<(or (and GPR:$src1, 0xFFFF0000),
-                   (and (srl GPR:$src2, imm1_15:$shamt), 0xFFFF)),
-               (PKHTB GPR:$src1, GPR:$src2, imm1_15:$shamt)>;
+                   (and (srl GPR:$src2, imm1_15:$sh), 0xFFFF)),
+               (PKHTB GPR:$src1, GPR:$src2, (asr_shift_imm imm1_15:$sh))>;
 
 //===----------------------------------------------------------------------===//
 //  Comparison Instructions...
diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index 26bfcae697..712593df50 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -2085,10 +2085,10 @@ def t2REVSH : T2I_misc<0b01, 0b11, (outs rGPR:$dst), (ins rGPR:$src), IIC_iUNAr,
                       (or (srl (and rGPR:$src, 0xFF00), (i32 8)),
                           (shl rGPR:$src, (i32 8))), i16))]>;
 
-def t2PKHBT : T2I<(outs rGPR:$dst), (ins rGPR:$src1, rGPR:$src2, i32imm:$shamt),
-                  IIC_iALUsi, "pkhbt", "\t$dst, $src1, $src2, lsl $shamt",
+def t2PKHBT : T2I<(outs rGPR:$dst), (ins rGPR:$src1, rGPR:$src2, shift_imm:$sh),
+                  IIC_iALUsi, "pkhbt", "\t$dst, $src1, $src2$sh",
                   [(set rGPR:$dst, (or (and rGPR:$src1, 0xFFFF),
-                                      (and (shl rGPR:$src2, (i32 imm:$shamt)),
+                                      (and (shl rGPR:$src2, lsl_amt:$sh),
                                            0xFFFF0000)))]>,
                   Requires<[HasT2ExtractPack]> {
   let Inst{31-27} = 0b11101;
@@ -2102,17 +2102,17 @@ def t2PKHBT : T2I<(outs rGPR:$dst), (ins rGPR:$src1, rGPR:$src2, i32imm:$shamt),
 def : T2Pat<(or (and rGPR:$src1, 0xFFFF), (and rGPR:$src2, 0xFFFF0000)),
             (t2PKHBT rGPR:$src1, rGPR:$src2, 0)>,
             Requires<[HasT2ExtractPack]>;
-def : T2Pat<(or (and rGPR:$src1, 0xFFFF), (shl rGPR:$src2, imm16_31:$shamt)),
-            (t2PKHBT rGPR:$src1, rGPR:$src2, imm16_31:$shamt)>,
+def : T2Pat<(or (and rGPR:$src1, 0xFFFF), (shl rGPR:$src2, imm16_31:$sh)),
+            (t2PKHBT rGPR:$src1, rGPR:$src2, (lsl_shift_imm imm16_31:$sh))>,
             Requires<[HasT2ExtractPack]>;
 
 // Note: Shifts of 1-15 bits will be transformed to srl instead of sra and
 // will match the pattern below.
-def t2PKHTB : T2I<(outs rGPR:$dst), (ins rGPR:$src1, rGPR:$src2, i32imm:$shamt),
-                  IIC_iALUsi, "pkhtb", "\t$dst, $src1, $src2, asr $shamt",
+def t2PKHTB : T2I<(outs rGPR:$dst), (ins rGPR:$src1, rGPR:$src2, shift_imm:$sh),
+                  IIC_iALUsi, "pkhtb", "\t$dst, $src1, $src2$sh",
                   [(set rGPR:$dst, (or (and rGPR:$src1, 0xFFFF0000),
-                                      (and (sra rGPR:$src2, imm16_31:$shamt),
-                                           0xFFFF)))]>,
+                                       (and (sra rGPR:$src2, asr_amt:$sh),
+                                            0xFFFF)))]>,
                   Requires<[HasT2ExtractPack]> {
   let Inst{31-27} = 0b11101;
   let Inst{26-25} = 0b01;
@@ -2124,11 +2124,11 @@ def t2PKHTB : T2I<(outs rGPR:$dst), (ins rGPR:$src1, rGPR:$src2, i32imm:$shamt),
 // Alternate cases for PKHTB where identities eliminate some nodes.  Note that
 // a shift amount of 0 is *not legal* here, it is PKHBT instead.
 def : T2Pat<(or (and rGPR:$src1, 0xFFFF0000), (srl rGPR:$src2, imm16_31:$sh)),
-            (t2PKHTB rGPR:$src1, rGPR:$src2, imm16_31:$sh)>,
+            (t2PKHTB rGPR:$src1, rGPR:$src2, (asr_shift_imm imm16_31:$sh))>,
             Requires<[HasT2ExtractPack]>;
 def : T2Pat<(or (and rGPR:$src1, 0xFFFF0000),
-                     (and (srl rGPR:$src2, imm1_15:$shamt), 0xFFFF)),
-            (t2PKHTB rGPR:$src1, rGPR:$src2, imm1_15:$shamt)>,
+                (and (srl rGPR:$src2, imm1_15:$sh), 0xFFFF)),
+            (t2PKHTB rGPR:$src1, rGPR:$src2, (asr_shift_imm imm1_15:$sh))>,
             Requires<[HasT2ExtractPack]>;
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp b/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
index 9637caaa57..e36935ac28 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
@@ -456,12 +456,20 @@ static inline ARM_AM::ShiftOpc getShiftOpcForBits(unsigned bits) {
 //
 // A8-11: DecodeImmShift()
 static inline void getImmShiftSE(ARM_AM::ShiftOpc &ShOp, unsigned &ShImm) {
-  // If type == 0b11 and imm5 == 0, we have an rrx, instead.
-  if (ShOp == ARM_AM::ror && ShImm == 0)
-    ShOp = ARM_AM::rrx;
-  // If (lsr or asr) and imm5 == 0, shift amount is 32.
-  if ((ShOp == ARM_AM::lsr || ShOp == ARM_AM::asr) && ShImm == 0)
+  if (ShImm != 0)
+    return;
+  switch (ShOp) {
+  case ARM_AM::lsl:
+    ShOp = ARM_AM::no_shift;
+    break;
+  case ARM_AM::lsr:
+  case ARM_AM::asr:
     ShImm = 32;
+    break;
+  case ARM_AM::ror:
+    ShOp = ARM_AM::rrx;
+    break;
+  }
 }
 
 // getAMSubModeForBits - getAMSubModeForBits translates from the ARM encoding
@@ -1445,7 +1453,13 @@ static bool DisassembleArithMiscFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
       && !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
     // Extract the 5-bit immediate field Inst{11-7}.
     unsigned ShiftAmt = (insn >> ARMII::ShiftShift) & 0x1F;
-    MI.addOperand(MCOperand::CreateImm(ShiftAmt));
+    ARM_AM::ShiftOpc Opc = ARM_AM::no_shift;
+    if (Opcode == ARM::PKHBT)
+      Opc = ARM_AM::lsl;
+    else if (Opcode == ARM::PKHBT)
+      Opc = ARM_AM::asr;
+    getImmShiftSE(Opc, ShiftAmt);
+    MI.addOperand(MCOperand::CreateImm(ARM_AM::getSORegOpc(Opc, ShiftAmt)));
     ++OpIdx;
   }
 
diff --git a/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h b/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
index 701c32a43c..112817b13c 100644
--- a/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
+++ b/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
@@ -220,7 +220,7 @@ static inline unsigned decodeImmShift(unsigned bits2, unsigned imm5,
   switch (bits2) {
   default: assert(0 && "No such value");
   case 0:
-    ShOp = ARM_AM::lsl;
+    ShOp = (imm5 == 0 ? ARM_AM::no_shift : ARM_AM::lsl);
     return imm5;
   case 1:
     ShOp = ARM_AM::lsr;
@@ -1389,14 +1389,7 @@ static bool DisassembleThumb2DPSoReg(MCInst &MI, unsigned Opcode, uint32_t insn,
       unsigned imm5 = getShiftAmtBits(insn);
       ARM_AM::ShiftOpc ShOp = ARM_AM::no_shift;
       unsigned ShAmt = decodeImmShift(bits2, imm5, ShOp);
-
-      // PKHBT/PKHTB are special in that we need the decodeImmShift() call to
-      // decode the shift amount from raw imm5 and bits2, but we DO NOT need
-      // to encode the ShOp, as it's in the asm string already.
-      if (Opcode == ARM::t2PKHBT || Opcode == ARM::t2PKHTB)
-        MI.addOperand(MCOperand::CreateImm(ShAmt));
-      else
-        MI.addOperand(MCOperand::CreateImm(ARM_AM::getSORegOpc(ShOp, ShAmt)));
+      MI.addOperand(MCOperand::CreateImm(ARM_AM::getSORegOpc(ShOp, ShAmt)));
     }
     ++OpIdx;
   }