Asm "p" constraint rejected

[llvmbot]

Bugzilla Link	9688
Version	2.9
OS	Linux
Blocks	llvm/llvm-bugzilla-archive#10988
Reporter	LLVM Bugzilla Contributor
CC	@RKSimon

Extended Description

From gcc testcase asm-4.c:

int main()
{
  int z;
  asm volatile ("test2 X%a0Y%a[arg]Z" : : [arg] "p" (&z));
}

Both clang and dragonegg reject this. See #8704 for discussion.

[arsenm]

clang still rejects this today while gcc accepts it:

	#APP
/tmp/issue10060.c:4:15: error: invalid operand in inline asm: 'test2 X${0:a}Y${0:a}Z'
    4 | asm volatile ("test2 X%a0Y%a[arg]Z" : : [arg] "p" (&z));
      |               ^
/tmp/issue10060.c:4:15: error: invalid operand in inline asm: 'test2 X${0:a}Y${0:a}Z'
/tmp/issue10060.c:4:15: error: invalid instruction mnemonic 'test2'
<inline asm>:1:2: note: instantiated into assembly here
    1 |         test2 XYZ
      |         ^~~~~
	#NO_APP

[shafik]

CC @AaronBallman do you have any opinions on whether we should accept this or not?

[AaronBallman]

I don't have strong opinions; assembly constraints are handled by the backend:

llvm-project/llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp

Line 316 in 1b74459

Msg << "invalid operand in inline asm: '" << AsmStr << "'";