-m32 inline asm: Do not know how to expand the result of this operator

[edwintorok]

Bugzilla Link	3390
Resolution	WONTFIX
Resolved on	Apr 17, 2019 16:56
Version	unspecified
OS	Linux
Depends On	llvm/llvm-bugzilla-archive#3391

Extended Description

After my attempt to fix the kernel to use same types for input/output regs, I get a failure on 32-bit:

Am I doing something wrong?

$ llvm-gcc testcase-min.i -m32
ExpandIntegerResult #​0: 0x28ce838: i64 = Register RCX
cc1: /home/edwin/llvm-bootstrap/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp:930: void llvm::DAGTypeLegalizer::ExpandIntegerResult(llvm::SDNode*, unsigned int): Assertion `0 && "Do not know how to expand the result of this operator!"' failed.
testcase-min.i:17: internal compiler error: Aborted
Please submit a full bug report,
with preprocessed source if appropriate.
See URL:http://developer.apple.com/bugreporter for instructions.

C reduced testcase below, bytecode attached:
/* testcase /
typedef unsigned int __kernel_size_t;
typedef long long __kernel_loff_t;
typedef __kernel_loff_t loff_t;
typedef __kernel_size_t size_t;
attribute ((regparm (0)))
long sys_sendfile64 (int out_fd, int in_fd, loff_t * offset,
size_t count)
{
if (offset)
{
if (__builtin_expect (!!((
{
typeof ((offset)) __ret_pu;
typeof ((offset)) __pu_val;
switch (sizeof ((offset)))
{
case 8:
asm volatile ("call __put_user_8": "=a" (__ret_pu): "A" ((typeof (*(offset))) (__pu_val)), "c" (offset):"ebx");}
(int) __ret_pu;}
)), 0))
return -14;
}
}

[edwintorok]

  asm volatile ("call __put_user_8": "=a" (__ret_pu): "A" ((typeof

(*(offset))) (__pu_val)), "c" (offset):"ebx");}

I guess problem is that output is 64-bit (A), but input is 32-bit, but __ret_pu is 64-bit due to my changes.

[llvmbot]

It looks like you are doing something wrong: "Register" is not
allowed to have an illegal type.

[edwintorok]

It looks like you are doing something wrong: "Register" is not
allowed to have an illegal type.

I've changed the code to use =A for the output too, and that seems to compile.

[edwintorok]

It looks like you are doing something wrong: "Register" is not
allowed to have an illegal type.

I've changed the code to use =A for the output too, and that seems to compile.

Correction: the reduced testcase compiles, the original file gets killed with out-of-memory, reducing a new testcase.

[edwintorok]

It looks like you are doing something wrong: "Register" is not
allowed to have an illegal type.

I've changed the code to use =A for the output too, and that seems to compile.

Correction: the reduced testcase compiles, the original file gets killed with
out-of-memory, reducing a new testcase.

#​3391 occured when I tried to fix the code to not use invalid "=a" constraint.

[llvmbot]

I believe, this isn't relevant any more.

[edwintorok]

mentioned in issue llvm/llvm-bugzilla-archive#3391