X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTarget%2FPowerPC%2FMCTargetDesc%2FPPCMCTargetDesc.h;h=8ff7e6c6f29582a467e8f75c27a124e70b2a08c8;hb=c16fc548515f2fd01bc2cbe4befd822a636cc154;hp=8b1e3b452a00d40643bf25a3f86c05209dae56a3;hpb=57849e3bb48269d8005ccd9939404ac7c4b072c4;p=oota-llvm.git

diff --git a/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.h b/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.h
index 8b1e3b452a0..8ff7e6c6f29 100644
--- a/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.h
+++ b/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.h
@@ -18,6 +18,7 @@
 #undef PPC
 
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/MathExtras.h"
 
 namespace llvm {
 class MCAsmBackend;
@@ -42,15 +43,44 @@ MCCodeEmitter *createPPCMCCodeEmitter(const MCInstrInfo &MCII,
 MCAsmBackend *createPPCAsmBackend(const Target &T, const MCRegisterInfo &MRI,
                                   StringRef TT, StringRef CPU);
 
-/// createPPCELFObjectWriter - Construct an PPC ELF object writer.
+/// Construct an PPC ELF object writer.
 MCObjectWriter *createPPCELFObjectWriter(raw_ostream &OS,
                                          bool Is64Bit,
                                          bool IsLittleEndian,
                                          uint8_t OSABI);
-/// createPPCELFObjectWriter - Construct a PPC Mach-O object writer.
+/// Construct a PPC Mach-O object writer.
 MCObjectWriter *createPPCMachObjectWriter(raw_ostream &OS, bool Is64Bit,
                                           uint32_t CPUType,
                                           uint32_t CPUSubtype);
+
+/// Returns true iff Val consists of one contiguous run of 1s with any number of
+/// 0s on either side.  The 1s are allowed to wrap from LSB to MSB, so
+/// 0x000FFF0, 0x0000FFFF, and 0xFF0000FF are all runs.  0x0F0F0000 is not,
+/// since all 1s are not contiguous.
+static inline bool isRunOfOnes(unsigned Val, unsigned &MB, unsigned &ME) {
+  if (!Val)
+    return false;
+
+  if (isShiftedMask_32(Val)) {
+    // look for the first non-zero bit
+    MB = countLeadingZeros(Val);
+    // look for the first zero bit after the run of ones
+    ME = countLeadingZeros((Val - 1) ^ Val);
+    return true;
+  } else {
+    Val = ~Val; // invert mask
+    if (isShiftedMask_32(Val)) {
+      // effectively look for the first zero bit
+      ME = countLeadingZeros(Val) - 1;
+      // effectively look for the first one bit after the run of zeros
+      MB = countLeadingZeros((Val - 1) ^ Val) + 1;
+      return true;
+    }
+  }
+  // no run present
+  return false;
+}
+
 } // End llvm namespace
 
 // Generated files will use "namespace PPC". To avoid symbol clash,