AArch64: add 'a' inline asm operand modifier

This is used in the Linux kernel, and effectively just means "print an
address".

llvm-svn: 193593

llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp

@@ -230,6 +230,8 @@ bool AArch64AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
     // Output bits 23:12 of symbolic address with appropriate :hi12: relocation
     // modifier (currently only for TLS local exec).
     return printSymbolicAddress(MI->getOperand(OpNum), true, "hi12", O);
+  case 'a':
+    return PrintAsmMemoryOperand(MI, OpNum, AsmVariant, ExtraCode, O);
   }
 
 

llvm/test/CodeGen/AArch64/inline-asm-modifiers.ll

@@ -107,3 +107,12 @@ define void @test_inline_modifier_c() nounwind {
 
   ret void
 }
+
+define void @test_inline_modifier_a() nounwind {
+; CHECK-LABEL: test_inline_modifier_a:
+  call void asm sideeffect "prfm pldl1keep, ${0:a}", "r"(i32* @var_simple)
+; CHECK: adrp [[VARHI:x[0-9]+]], var_simple
+; CHECK: add x[[VARADDR:[0-9]+]], [[VARHI]], #:lo12:var_simple
+; CHECK: prfm pldl1keep, [x[[VARADDR]]]
+  ret void
+}