[X86] Classify the AVX512 rounding control operand as X86::OPERAND_ROUNDING_CONTROL instead of MCOI::OPERAND_IMMEDIATE. Add an assert on legal values of rounding control in the encoder and remove an explicit mask.

This should allow llvm-exegesis to intelligently constrain the rounding mode.

The mask in the encoder shouldn't be necessary any more. We used to allow codegen to use 8-11 for rounding mode and the assembler would use 0-3 to mean the same thing so we masked here and in the printer. Codegen now matches the assembler and the printer was updated, but I forgot to update the encoder.

llvm-svn: 357419

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp
index fd95387b076..353f52a8c20 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp
@@ -879,7 +879,8 @@ void X86MCCodeEmitter::EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
       if (HasEVEX_RC) {
         unsigned RcOperand = NumOps-1;
         assert(RcOperand >= CurOp);
-        EVEX_rc = MI.getOperand(RcOperand).getImm() & 0x3;
+        EVEX_rc = MI.getOperand(RcOperand).getImm();
+        assert(EVEX_rc <= 3 && "Invalid rounding control!");
       }
       EncodeRC = true;
     }