[PATCH] D66057: [InstCombine] Shift amount reassociation in bittest: trunc-of-shl (PR42399)

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp:3315-3321
+  Instruction *XShift, *MaybeTruncation, *YShift;
+  if (!match(
+          I.getOperand(0),
+          m_c_And(m_CombineAnd(m_AnyLogicalShift, m_Instruction(XShift)),
+                  m_CombineAnd(m_TruncOrSelf(m_CombineAnd(
+                                   m_AnyLogicalShift, m_Instruction(YShift))),
+                               m_Instruction(MaybeTruncation)))))
----------------
spatel wrote:
> Can we make the change to use Instruction*/m_Instruction independently (ie as a pre-commit) of this patch?
> (I'd be fine without requiring a weird ConstExpr test to prove the diff if that was a possibility.)
I actually already did that in rL368554 to fix https://bugs.llvm.org/show_bug.cgi?id=42962
I just need to rebase this, hold on..


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D66057/new/

https://reviews.llvm.org/D66057