AArch64: Simplify logic in deciding whether bfi is valid

Previous code had a confusing comment which was mostly an implementation
detail. This condition corresponds to "lsb up to register width" and "width not
ridiculous".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174877 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp b/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
index bab7d849d058f44ea83449f90914a7d870066d4c..1cdeafb4dc29b85f156d6c48c734ada2713f2c0a 100644 (file)
--- a/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
+++ b/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -1725,12 +1725,7 @@ validateInstruction(MCInst &Inst,
     int64_t ImmR = Inst.getOperand(ImmOps).getImm();
     int64_t ImmS = Inst.getOperand(ImmOps+1).getImm();
 
-    if (ImmR == 0) {
-      // Bitfield inserts are preferred disassembly if ImmS < ImmR. However,
-      // there is this one case where insert is valid syntax but the bfx
-      // disassembly should be used: e.g. "sbfiz w0, w0, #0, #1".
-      return false;
-    } else if (ImmS >= ImmR) {
+    if (ImmR != 0 && ImmS >= ImmR) {
       return Error(Operands[4]->getStartLoc(),
                    "requested insert overflows register");
     }