Would it be better to change the common CHECK to RV32 in rv32 tests, and RV64 in rv64 tests ?

It is my mistake. I should add --author=Ping Deng <Ping.Deng@streamcomputing.com> when doing git commit.

Change the title to [clang][Driver] Add more tests for riscv

It is hard to make a test for my change, since operand memspi is used only by the STDSPQRr and STDWSPQRr pseudo instructions. Adding PrintMethod is just for debug purpose, and we should see no pseudo instruction in the final assembly file.

@Patryk27 Could you please have a look at this change? I find this bug when debugging your https://reviews.llvm.org/D123528. The STDSPQRr & STDWSPQRr are printed with the offset vaule.

In D125077#3496592, @aykevl wrote:

Looks good to me. It might be possible to optimize these functions a bit more but that can happen at a later time.

Corresponding tests

The new implementation of __mulhi3 and __mulqi3 strictly follow libgcc's special ABI.

In D123200#3495356, @aykevl wrote:

@benshi001 I have been looking through the GCC code and I think avr-gcc also has a special calling convention for many other functions, including __mulqi3 and __mulhi3.

Source:

1. I think this is where the ABI is specified in the compiler: https://github.com/gcc-mirror/gcc/blob/releases/gcc-5.4.0/gcc/config/avr/avr.md#L1543-L1549 You can see that it multiplies R24 with R22 and stores the result in R24, and clobbers R22 in the process. But no other registers.
2. In this code sample, avr-gcc doesn't save char c (r20) across the __mulqi3 and __mulhi3 calls, which is normally call-clobbered.

Therefore, I think we need to be a bit more careful with defining these AVR builtins and check the ABI in avr-gcc first.
Also, we can make use of this and optimize the AVR backend more (you can see that the Clang generated code is much worse than avr-gcc in the above examples).

The variable STI is only used in assert, so there will be 'used variable' warnings when doing release build.

.

In D124600#3492627, @aykevl wrote:

The following code produces __divmodqi4, so I think it is still needed:

define i8 @divqi4(i8 %a, i8 %b) addrspace(1) {
  %result = sdiv i8 %a, %b
  ret i8 %result
}

See: https://llvm.godbolt.org/z/nTbcTfbb7