Recognize inline asm 'rev /bin/bash, ' as a bswap intrinsic call.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123048 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARMBaseInstrInfo.cpp

@@ -2071,7 +2071,6 @@ ARMBaseInstrInfo::getOperandLatency(const InstrItineraryData *ItinData,
   if (!ItinData || ItinData->isEmpty())
     return DefTID.mayLoad() ? 3 : 1;
 
-
   const TargetInstrDesc &UseTID = UseMI->getDesc();
   const MachineOperand &DefMO = DefMI->getOperand(DefIdx);
   if (DefMO.getReg() == ARM::CPSR) {

lib/Target/ARM/ARMISelLowering.cpp

@@ -33,6 +33,7 @@
 #include "llvm/Intrinsics.h"
 #include "llvm/Type.h"
 #include "llvm/CodeGen/CallingConvLower.h"
+#include "llvm/CodeGen/IntrinsicLowering.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
@@ -43,6 +44,7 @@
 #include "llvm/MC/MCSectionMachO.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/ADT/VectorExtras.h"
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -6092,6 +6094,37 @@ void ARMTargetLowering::computeMaskedBitsForTargetNode(const SDValue Op,
 //                           ARM Inline Assembly Support
 //===----------------------------------------------------------------------===//
 
+bool ARMTargetLowering::ExpandInlineAsm(CallInst *CI) const {
+  // Looking for "rev" which is V6+.
+  if (!Subtarget->hasV6Ops())
+    return false;
+
+  InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
+  std::string AsmStr = IA->getAsmString();
+  SmallVector<StringRef, 4> AsmPieces;
+  SplitString(AsmStr, AsmPieces, ";\n");
+
+  switch (AsmPieces.size()) {
+  default: return false;
+  case 1:
+    AsmStr = AsmPieces[0];
+    AsmPieces.clear();
+    SplitString(AsmStr, AsmPieces, " \t,");
+
+    // rev $0, $1
+    if (AsmPieces.size() == 3 &&
+        AsmPieces[0] == "rev" && AsmPieces[1] == "$0" && AsmPieces[2] == "$1" &&
+        IA->getConstraintString().compare(0, 4, "=l,l") == 0) {
+      const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
+      if (Ty && Ty->getBitWidth() == 32)
+        return IntrinsicLowering::LowerToByteSwap(CI);
+    }
+    break;
+  }
+
+  return false;
+}
+
 /// getConstraintType - Given a constraint letter, return the type of
 /// constraint it is for this target.
 ARMTargetLowering::ConstraintType

lib/Target/ARM/ARMISelLowering.h

@@ -257,6 +257,8 @@ namespace llvm {
                                                 unsigned Depth) const;
 
 
+    virtual bool ExpandInlineAsm(CallInst *CI) const;
+
     ConstraintType getConstraintType(const std::string &Constraint) const;
 
     /// Examine constraint string and operand type and determine a weight value.