Replace some bit operations with simpler ones. No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182226 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 9 insertions, 12 deletions

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 479fb77..c9ee5fb 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -10434,17 +10434,15 @@ ARMTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
 
 bool ARM::isBitFieldInvertedMask(unsigned v) {
   if (v == 0xffffffff)
-    return 0;
+    return false;
+
   // there can be 1's on either or both "outsides", all the "inside"
   // bits must be 0's
-  unsigned int lsb = 0, msb = 31;
-  while (v & (1 << msb)) --msb;
-  while (v & (1 << lsb)) ++lsb;
-  for (unsigned int i = lsb; i <= msb; ++i) {
-    if (v & (1 << i))
-      return 0;
-  }
-  return 1;
+  unsigned TO = CountTrailingOnes_32(v);
+  unsigned LO = CountLeadingOnes_32(v);
+  v = (v >> TO) << TO;
+  v = (v << LO) >> LO;
+  return v == 0;
 }
 
 /// isFPImmLegal - Returns true if the target can instruction select the
diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 4d3bf34..b6b1d4d 100644
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -7423,8 +7423,7 @@ processInstruction(MCInst &Inst,
     unsigned TZ = CountTrailingZeros_32(Mask);
     if ((Inst.getOperand(0).getImm() & 1) == 0) {
       assert(Mask && TZ <= 3 && "illegal IT mask value!");
-      for (unsigned i = 3; i != TZ; --i)
-        Mask ^= 1 << i;
+      Mask ^= (0xE << TZ) & 0xF;
     }
     MO.setImm(Mask);
 
diff --git a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index d289637..c562cf7 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -1224,7 +1224,7 @@ static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
   }
 
   // Empty register lists are not allowed.
-  if (CountPopulation_32(Val) == 0) return MCDisassembler::Fail;
+  if (Val == 0) return MCDisassembler::Fail;
   for (unsigned i = 0; i < 16; ++i) {
     if (Val & (1 << i)) {
       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))