Fixed the arm disassembly of invalid BFI instructions to not build a bad MCInst
which would then cause an assert when printed. rdar://11437956
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168960 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index f00142d..5de50d5 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -1281,7 +1281,13 @@
unsigned lsb = fieldFromInstruction(Val, 0, 5);
DecodeStatus S = MCDisassembler::Success;
- if (lsb > msb) Check(S, MCDisassembler::SoftFail);
+ if (lsb > msb) {
+ Check(S, MCDisassembler::SoftFail);
+ // The check above will cause the warning for the "potentially undefined
+ // instruction encoding" but we can't build a bad MCOperand value here
+ // with a lsb > msb or else printing the MCInst will cause a crash.
+ lsb = msb;
+ }
uint32_t msb_mask = 0xFFFFFFFF;
if (msb != 31) msb_mask = (1U << (msb+1)) - 1;