[PATCH] D77453: [GlobalISel] Simplify G_ADD when it has (0-X) on the LHS or RHS

[Matt Arsenault via Phabricator via llvm-commits]

arsenm accepted this revision.
arsenm added a comment.
This revision is now accepted and ready to land.
Herald added a project: LLVM.

LGTM. InstCombine seems to not preserve flags in this case



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Comment at: llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp:1619-1620
+    int64_t Cst;
+    if (!mi_match(MaybeSub, MRI, m_GSub(m_ICst(Cst), m_Reg(NewRHS))) ||
+        Cst != 0)
+      return false;
----------------
We should add an m_Zero() at some point


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  https://reviews.llvm.org/D77453/new/

https://reviews.llvm.org/D77453