[mlir] Inconsistent results for arith.ceildivsi

[AnonymousBugreporter1]

I have the following MLIR program:
test.mlir:

module {
  func.func @func1() -> f32 {
    %c1189465982_i64 = arith.constant 1189465982 : i64
    %c-9223372036854775808_i64 = arith.constant -9223372036854775808 : i64
    %156 = arith.ceildivsi %c-9223372036854775808_i64, %c1189465982_i64 : i64
    vector.print %156 : i64
    %0 = arith.sitofp %156 : i64 to f32
    return %0 : f32
  }
}

When I ran /data/tmp/v1107/llvm-project/build/bin/mlir-opt --int-range-optimizations --arith-expand --convert-arith-to-llvm --convert-vector-to-llvm --convert-func-to-llvm --reconcile-unrealized-casts test.mlir | /data/tmp/v1107/llvm-project/build/bin/mlir-cpu-runner -e func1 --shared-libs=/data/tmp/v1107/llvm-project/build/lib/libmlir_runner_utils.so,/data/tmp/v1107/llvm-project/build/lib/libmlir_c_runner_utils.so on the program, I got the result of:

-7754212542
-7.754212e+09

However, when I ran /data/tmp/v1107/llvm-project/build/bin/mlir-opt --arith-expand --convert-arith-to-llvm --convert-vector-to-llvm --convert-func-to-llvm --reconcile-unrealized-casts test.mlir | /data/tmp/v1107/llvm-project/build/bin/mlir-cpu-runner -e func1 --shared-libs=/data/tmp/v1107/llvm-project/build/lib/libmlir_runner_utils.so,/data/tmp/v1107/llvm-project/build/lib/libmlir_c_runner_utils.so on the program, I got the result of:

7754212542
7.754212e+09

The above two results seem to be inconsistent. I'm not sure if there is any bug in my program or if the wrong usage of the above passes caused these results.

My git version is 1469d82.

[AnonymousBugreporter1]

I tried to reproduce this issue on history commit versions, and I found these inconsistence results can be reproduced on commit 4722911, and cannot be reproduced on the previous commit 3e39328. Hi @krzysz00, sorry to disturb but I was wondering if you would mind taking a look at this problem?

[krzysz00]

@Mogball @River707 Having stared at this (and noticed that --arith-expand-ops --canonicalize on the input gives a simpler reproducer), I think the expansion of CeilDivSI is incorrect - a negative number divided by a positive number, rounded up, should still be negative.

[krzysz00]

On further investigation, the issue is that --arith-expand isn't lowering to logic that handles a ceildiv b where a = INT_MIN , which overflows.

From where I'm standing:

1. In arbitrary precision, the negative result is correct
2. The positive result isn't unreasonable for some of the usual ceil_div functions you can find out there

I suspect that, since it looks like this is defined behavior, I need to go add some cases to integer range analysis

[llvmbot]

@llvm/issue-subscribers-mlir

Author: None (wangyongj1a)

I have the following MLIR program: test.mlir: ``` module { func.func @func1() -> f32 { %c1189465982_i64 = arith.constant 1189465982 : i64 %c-9223372036854775808_i64 = arith.constant -9223372036854775808 : i64 %156 = arith.ceildivsi %c-9223372036854775808_i64, %c1189465982_i64 : i64 vector.print %156 : i64 %0 = arith.sitofp %156 : i64 to f32 return %0 : f32 } } ``` When I ran ```/data/tmp/v1107/llvm-project/build/bin/mlir-opt --int-range-optimizations --arith-expand --convert-arith-to-llvm --convert-vector-to-llvm --convert-func-to-llvm --reconcile-unrealized-casts test.mlir | /data/tmp/v1107/llvm-project/build/bin/mlir-cpu-runner -e func1 --shared-libs=/data/tmp/v1107/llvm-project/build/lib/libmlir_runner_utils.so,/data/tmp/v1107/llvm-project/build/lib/libmlir_c_runner_utils.so``` on the program, I got the result of: ``` -7754212542 -7.754212e+09 ``` However, when I ran ```/data/tmp/v1107/llvm-project/build/bin/mlir-opt --arith-expand --convert-arith-to-llvm --convert-vector-to-llvm --convert-func-to-llvm --reconcile-unrealized-casts test.mlir | /data/tmp/v1107/llvm-project/build/bin/mlir-cpu-runner -e func1 --shared-libs=/data/tmp/v1107/llvm-project/build/lib/libmlir_runner_utils.so,/data/tmp/v1107/llvm-project/build/lib/libmlir_c_runner_utils.so``` on the program, I got the result of: ``` 7754212542 7.754212e+09 ```

The above two results seem to be inconsistent. I'm not sure if there is any bug in my program or if the wrong usage of the above passes caused these results.

My git version is 1469d82.