[llvm] [AArch64][GlobalISel] Push ADD/SUB through Extend Instructions (PR #90964)

[Thorsten Schütt via llvm-commits]

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@@ -52,14 +52,31 @@ def ext_uaddv_to_uaddlv : GICombineRule<
   (apply [{ applyExtUaddvToUaddlv(*${root}, MRI, B, Observer, ${matchinfo}); }])
 >;
 
+class push_opcode_through_ext<Instruction opcode, Instruction extOpcode> : GICombineRule <
+  (defs root:$root),
+  (match (extOpcode $ext1, $src1):$ExtMI,
+         (extOpcode $ext2, $src2),
+         (opcode $dst, $ext1, $ext2):$root,
+         [{ return matchPushAddSubExt(*${root}, MRI, ${dst}.getReg(), ${src1}.getReg(), ${src2}.getReg()); }]),
+  (apply [{ applyPushAddSubExt(*${root}, MRI, B, ${ExtMI}->getOpcode() == TargetOpcode::G_SEXT, ${dst}.getReg(), ${src1}.getReg(), ${src2}.getReg()); }])>;
+
+def push_sub_through_zext : push_opcode_through_ext<G_SUB, G_ZEXT>;
+def push_add_through_zext : push_opcode_through_ext<G_ADD, G_ZEXT>;
+def push_sub_through_sext : push_opcode_through_ext<G_SUB, G_SEXT>;
+def push_add_through_sext : push_opcode_through_ext<G_ADD, G_SEXT>;
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tschuett wrote:

Nice!

https://github.com/llvm/llvm-project/pull/90964