[all-commits] [llvm/llvm-project] 77434c: [DAGCombiner] Teach `reduceLoadWidth` to look past...

[Henry Jiang via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 77434ce19a48c519f8c90043e94fc602d6f86de9
      https://github.com/llvm/llvm-project/commit/77434ce19a48c519f8c90043e94fc602d6f86de9
  Author: Henry Jiang <henry_jiang2 at apple.com>
  Date:   2026-04-30 (Thu, 30 Apr 2026)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    M llvm/test/CodeGen/AArch64/load-store-forwarding.ll
    A llvm/test/CodeGen/AArch64/reduce-load-width-freeze.ll
    M llvm/test/CodeGen/PowerPC/widen-vec-correctly-be.ll
    M llvm/test/CodeGen/RISCV/bitint-fp-conv-200.ll
    M llvm/test/CodeGen/X86/and-mask-variable.ll
    M llvm/test/CodeGen/X86/bit-manip-i256.ll
    M llvm/test/CodeGen/X86/bit-manip-i512.ll
    M llvm/test/CodeGen/X86/freeze-vector.ll
    A llvm/test/CodeGen/X86/reduce-load-width-freeze.ll
    M llvm/test/CodeGen/X86/select.ll
    M llvm/test/CodeGen/X86/shift-i128.ll
    M llvm/test/CodeGen/X86/shift-i256.ll
    M llvm/test/CodeGen/X86/shift-i512.ll

  Log Message:
  -----------
  [DAGCombiner] Teach `reduceLoadWidth` to look past `ISD:FREEZE` (#189317)

Teach `DAGCombiner::reduceLoadWidth` to look through freeze SDNodes when
narrowing loads. The narrowed result is then wrapped in freeze to
preserve the original semantics. Currently, several folds were blocked
by the freeze:
```
and(freeze(load), 0xff) -> AssertZext(freeze(zextload, i8))
trunc(freeze(load i32), i8) -> freeze(load i8)
sext_inreg(freeze(load), i8) -> AssertSext(freeze(sextload, i8))
```
and many other patterns due to legalizer or upstream IR passes inserting
freeze. This generally has the positive effects of narrowing the load
type.



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