[PATCH] D109357: [GlobalISel] Add a combine for and(load , mask) -> zextload

[Jay Foad via Phabricator via llvm-commits]

foad added inline comments.


================
Comment at: llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp:668
+  Register PtrReg = LoadMI->getPointerReg();
+  unsigned NewSize = std::min((uint64_t)MaskVal.countTrailingOnes(),
+                              LoadMI->getMemSizeInBits());
----------------
This looks like it will combine:
```
    %1:_(s32) = G_CONSTANT i32 65535
    %2:_(s32) = G_SEXTLOAD %0 :: (load (s8))
    %3:_(s32) = G_AND %2, %1
```
into:
```
    %2:_(s32) = G_ZEXTLOAD %0 :: (load (s8))
```
which would be wrong.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D109357/new/

https://reviews.llvm.org/D109357