Refactor IT handling not to store the bottom bit of the condition code in the mask operand in the MCInst.

llvm-svn: 155700

3 files changed, 7 insertions, 14 deletions

diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 69c9d45b128..fdefe43bb88 100644
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -7214,9 +7214,7 @@ processInstruction(MCInst &Inst,
     // The mask bits for all but the first condition are represented as
     // the low bit of the condition code value implies 't'. We currently
     // always have 1 implies 't', so XOR toggle the bits if the low bit
-    // of the condition code is zero. The encoding also expects the low
-    // bit of the condition to be encoded as bit 4 of the mask operand,
-    // so mask that in if needed
+    // of the condition code is zero. 
     MCOperand &MO = Inst.getOperand(1);
     unsigned Mask = MO.getImm();
     unsigned OrigMask = Mask;
@@ -7225,8 +7223,7 @@ processInstruction(MCInst &Inst,
       assert(Mask && TZ <= 3 && "illegal IT mask value!");
       for (unsigned i = 3; i != TZ; --i)
         Mask ^= 1 << i;
-    } else
-      Mask |= 0x10;
+    }
     MO.setImm(Mask);
 
     // Set up the IT block state according to the IT instruction we just
diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 81a61fe9646..49260bbbf28 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -63,7 +63,7 @@ namespace {
       // fields in the IT instruction encoding.
       void setITState(char Firstcond, char Mask) {
         // (3 - the number of trailing zeros) is the number of then / else.
-        unsigned CondBit0 = Mask >> 4 & 1;
+        unsigned CondBit0 = Firstcond & 1;
         unsigned NumTZ = CountTrailingZeros_32(Mask);
         unsigned char CCBits = static_cast<unsigned char>(Firstcond & 0xf);
         assert(NumTZ <= 3 && "Invalid IT mask!");
@@ -4217,19 +4217,14 @@ static DecodeStatus DecodeIT(MCInst &Inst, unsigned Insn,
                              uint64_t Address, const void *Decoder) {
   DecodeStatus S = MCDisassembler::Success;
   unsigned pred = fieldFromInstruction16(Insn, 4, 4);
-  // The InstPrinter needs to have the low bit of the predicate in
-  // the mask operand to be able to print it properly.
-  unsigned mask = fieldFromInstruction16(Insn, 0, 5);
+  unsigned mask = fieldFromInstruction16(Insn, 0, 4);
 
   if (pred == 0xF) {
     pred = 0xE;
     S = MCDisassembler::SoftFail;
   }
 
-  if ((mask & 0xF) == 0) {
-    // Preserve the high bit of the mask, which is the low bit of
-    // the predicate.
-    mask &= 0x10;
+  if (mask == 0x0) {
     mask |= 0x8;
     S = MCDisassembler::SoftFail;
   }
diff --git a/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp b/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
index cbd81c11a45..34a76b27ea5 100644
--- a/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
+++ b/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
@@ -754,7 +754,8 @@ void ARMInstPrinter::printThumbITMask(const MCInst *MI, unsigned OpNum,
                                       raw_ostream &O) {
   // (3 - the number of trailing zeros) is the number of then / else.
   unsigned Mask = MI->getOperand(OpNum).getImm();
-  unsigned CondBit0 = Mask >> 4 & 1;
+  unsigned Firstcond = MI->getOperand(OpNum-1).getImm();
+  unsigned CondBit0 = Firstcond & 1;
   unsigned NumTZ = CountTrailingZeros_32(Mask);
   assert(NumTZ <= 3 && "Invalid IT mask!");
   for (unsigned Pos = 3, e = NumTZ; Pos > e; --Pos) {