[llvm] [RISCV] Add a pass to remove ADDI by reassociating to fold into load/store address. (PR #127151)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ml-opt-dev-x86-64` running on `ml-opt-dev-x86-64-b2` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/137/builds/13630

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/RISCV/fold-mem-offset.ll' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: sed 's/iXLen/i32/g' /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/fold-mem-offset.ll | /b/ml-opt-dev-x86-64-b1/build/bin/llc -mtriple=riscv32 | /b/ml-opt-dev-x86-64-b1/build/bin/FileCheck /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/fold-mem-offset.ll --check-prefixes=CHECK,RV32I
+ sed s/iXLen/i32/g /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/fold-mem-offset.ll
+ /b/ml-opt-dev-x86-64-b1/build/bin/FileCheck /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/fold-mem-offset.ll --check-prefixes=CHECK,RV32I
+ /b/ml-opt-dev-x86-64-b1/build/bin/llc -mtriple=riscv32
/b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/fold-mem-offset.ll:16:15: error: RV32I-NEXT: expected string not found in input
; RV32I-NEXT: lw a3, 400(a0)
              ^
<stdin>:16:16: note: scanning from here
 lw a1, 484(a1)
               ^
<stdin>:17:2: note: possible intended match here
 lw a3, 404(a0)
 ^
/b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/fold-mem-offset.ll:216:15: error: RV32I-NEXT: expected string not found in input
; RV32I-NEXT: lw a2, 400(a1)
              ^
<stdin>:92:16: note: scanning from here
 add a0, a0, a2
               ^
<stdin>:94:2: note: possible intended match here
 lw a3, 400(a1)
 ^

Input file: <stdin>
Check file: /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/fold-mem-offset.ll

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            .
            .
            .
           11:  slli a1, a1, 3 
           12:  slli a2, a2, 3 
           13:  add a1, a1, a0 
           14:  add a0, a0, a2 
           15:  lw a2, 480(a1) 
           16:  lw a1, 484(a1) 
next:16'0                     X error: no match found
           17:  lw a3, 404(a0) 
next:16'0      ~~~~~~~~~~~~~~~~
next:16'1       ?               possible intended match
           18:  lw a4, 400(a0) 
next:16'0      ~~~~~~~~~~~~~~~~
...

```

</details>

https://github.com/llvm/llvm-project/pull/127151