Doubleword Shift Left Logical Plus 32

Mips shift instructions DSLL, DSRL and DSRA are transformed into
DSLL32, DSRL32 and DSRA32 respectively if the shift amount is between
32 and 63

Here is a description of DSLL:

Purpose: Doubleword Shift Left Logical Plus 32
To execute a left-shift of a doubleword by a fixed amount--32 to 63 bits

Description: GPR[rd] <- GPR[rt] << (sa+32)

The 64-bit doubleword contents of GPR rt are shifted left, inserting
 zeros into the emptied bits; the result is placed in
GPR rd. The bit-shift amount in the range 0 to 31 is specified by sa.

This patch implements the direct object output of these instructions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160277 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 57 insertions, 1 deletions

diff --git a/lib/Target/Mips/Mips64InstrInfo.td b/lib/Target/Mips/Mips64InstrInfo.td
index 7a9d41b..cceee24 100644
--- a/lib/Target/Mips/Mips64InstrInfo.td
+++ b/lib/Target/Mips/Mips64InstrInfo.td
@@ -109,6 +109,11 @@ def DSRA     : shift_rotate_imm64<0x3b, 0x00, "dsra", sra>;
 def DSLLV    : shift_rotate_reg<0x14, 0x00, "dsllv", shl, CPU64Regs>;
 def DSRLV    : shift_rotate_reg<0x16, 0x00, "dsrlv", srl, CPU64Regs>;
 def DSRAV    : shift_rotate_reg<0x17, 0x00, "dsrav", sra, CPU64Regs>;
+let Pattern = []<dag> in {
+def DSLL32   : shift_rotate_imm64<0x3c, 0x00, "dsll32", shl>;
+def DSRL32   : shift_rotate_imm64<0x3e, 0x00, "dsrl32", srl>;
+def DSRA32   : shift_rotate_imm64<0x3f, 0x00, "dsra32", sra>;
+}
 }
 // Rotate Instructions
 let Predicates = [HasMips64r2, HasStandardEncoding],
diff --git a/lib/Target/Mips/MipsAsmPrinter.cpp b/lib/Target/Mips/MipsAsmPrinter.cpp
index 4dac591..914a204 100644
--- a/lib/Target/Mips/MipsAsmPrinter.cpp
+++ b/lib/Target/Mips/MipsAsmPrinter.cpp
@@ -13,9 +13,10 @@
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "mips-asm-printer"
-#include "MipsAsmPrinter.h"
 #include "Mips.h"
+#include "MipsAsmPrinter.h"
 #include "MipsInstrInfo.h"
+#include "MipsMCInstLower.h"
 #include "InstPrinter/MipsInstPrinter.h"
 #include "MCTargetDesc/MipsBaseInfo.h"
 #include "llvm/ADT/SmallString.h"
@@ -57,6 +58,25 @@ void MipsAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     return;
   }
 
+  // Direct object specific instruction lowering
+  if (!OutStreamer.hasRawTextSupport())
+    switch (MI->getOpcode()) {
+    case Mips::DSLL:
+    case Mips::DSRL:
+    case Mips::DSRA:
+      assert(MI->getNumOperands() == 3 &&
+             "Invalid no. of machine operands for shift!");
+      assert(MI->getOperand(2).isImm());
+      int64_t Shift = MI->getOperand(2).getImm();
+      if (Shift > 31) {
+        MCInst TmpInst0;
+        MCInstLowering.LowerLargeShift(MI, TmpInst0, Shift - 32);
+        OutStreamer.EmitInstruction(TmpInst0);
+        return;
+      }
+      break;
+    }
+
   MachineBasicBlock::const_instr_iterator I = MI;
   MachineBasicBlock::const_instr_iterator E = MI->getParent()->instr_end();
 
diff --git a/lib/Target/Mips/MipsMCInstLower.cpp b/lib/Target/Mips/MipsMCInstLower.cpp
index b6042af..c49d530 100644
--- a/lib/Target/Mips/MipsMCInstLower.cpp
+++ b/lib/Target/Mips/MipsMCInstLower.cpp
@@ -158,3 +158,32 @@ void MipsMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
       OutMI.addOperand(MCOp);
   }
 }
+
+// If the D<shift> instruction has a shift amount that is greater
+// than 31 (checked in calling routine), lower it to a D<shift>32 instruction
+void MipsMCInstLower::LowerLargeShift(const MachineInstr *MI,
+                                      MCInst& Inst,
+                                      int64_t Shift) {
+  // rt
+  Inst.addOperand(LowerOperand(MI->getOperand(0)));
+  // rd
+  Inst.addOperand(LowerOperand(MI->getOperand(1)));
+  // saminus32
+  Inst.addOperand(MCOperand::CreateImm(Shift));
+
+  switch (MI->getOpcode()) {
+  default:
+    // Calling function is not synchronized
+    llvm_unreachable("Unexpected shift instruction");
+    break;
+  case Mips::DSLL:
+    Inst.setOpcode(Mips::DSLL32);
+    break;
+  case Mips::DSRL:
+    Inst.setOpcode(Mips::DSRL32);
+    break;
+  case Mips::DSRA:
+    Inst.setOpcode(Mips::DSRA32);
+    break;
+  }
+}
diff --git a/lib/Target/Mips/MipsMCInstLower.h b/lib/Target/Mips/MipsMCInstLower.h
index 314420a..0abb996 100644
--- a/lib/Target/Mips/MipsMCInstLower.h
+++ b/lib/Target/Mips/MipsMCInstLower.h
@@ -33,6 +33,8 @@ public:
   MipsMCInstLower(MipsAsmPrinter &asmprinter);
   void Initialize(Mangler *mang, MCContext *C);
   void Lower(const MachineInstr *MI, MCInst &OutMI) const;
+  void LowerLargeShift(const MachineInstr *MI, MCInst &Inst, int64_t Shift);
+
 private:
   MCOperand LowerSymbolOperand(const MachineOperand &MO,
                                MachineOperandType MOTy, unsigned Offset) const;