Add TEST8ri_NOREX pseudo to constrain sub_8bit_hi copies.

In 64-bit mode, sub_8bit_hi sub-registers can only be used by NOREX
instructions. The COPY created from the EXTRACT_SUBREG DAG node cannot
target all GR8 registers, only those in GR8_NOREX.

TO enforce this, we ensure that all instructions using the
EXTRACT_SUBREG are GR8_NOREX constrained.

This fixes PR11088.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141499 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/Target/X86/X86InstrArithmetic.td b/lib/Target/X86/X86InstrArithmetic.td
index 6d2c53495c..f6ed722c07 100644
--- a/lib/Target/X86/X86InstrArithmetic.td
+++ b/lib/Target/X86/X86InstrArithmetic.td
@@ -1145,5 +1145,11 @@ let Defs = [EFLAGS] in {
                            "{$src, %eax|EAX, $src}">;
   def TEST64i32  : BinOpAI<0xA8, "test", Xi64, RAX,
                            "{$src, %rax|RAX, $src}">;
+
+  // When testing the result of EXTRACT_SUBREG sub_8bit_hi, make sure the
+  // register class is constrained to GR8_NOREX.
+  let isPseudo = 1 in
+  def TEST8ri_NOREX : I<0, Pseudo, (outs), (ins GR8_NOREX:$src, i8imm:$mask),
+                        "", []>;
 }