[AMDGPU][GlobalISel] Assertion failure in constant folding in buildPtrAdd

[jayfoad]

On this test case I get:

$ llc -mtriple=amdgcn -mcpu=gfx1030 -global-isel r.ll
llc: lib/Support/APInt.cpp:198: llvm::APInt &llvm::APInt::operator+=(const llvm::APInt &): Assertion `BitWidth == RHS.BitWidth && "Bit widths must be the same"' failed.

[llvmbot]

@llvm/issue-subscribers-backend-amdgpu

Author: Jay Foad (jayfoad)

On this [test case](https://github.com/llvm/llvm-project/files/14237614/r.txt) I get: ``` $ llc -mtriple=amdgcn -mcpu=gfx1030 -global-isel r.ll llc: lib/Support/APInt.cpp:198: llvm::APInt &llvm::APInt::operator+=(const llvm::APInt &): Assertion `BitWidth == RHS.BitWidth && "Bit widths must be the same"' failed. ```

[tschuett]

You are probably the next one hitting:

llvm-project/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp

Line 1170 in b726a81

bool CombinerHelper::matchCombineExtractedVectorLoad(MachineInstr &MI,

Differences: address spaces and nullptr.