[llvm] [AArch64][InstCombine] xor(cmpne) -> cmpeq (PR #207007)

[Paul Walker via llvm-commits]

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@@ -2142,10 +2142,43 @@ static std::optional<Instruction *> instCombineSVEDupX(InstCombiner &IC,
   return IC.replaceInstUsesWith(II, Splat);
 }
 
+static std::optional<Instruction *> instCombineXorSVECmpNE(InstCombiner &IC,
+                                                           IntrinsicInst &II) {
+  if (!match(II.getOperand(2), m_Zero()) || !II.hasOneUse())
+    return std::nullopt;
+
+  auto *User = cast<Instruction>(*II.user_begin());
+  if (!match(User, m_c_Xor(m_Specific(&II), m_Specific(II.getOperand(0)))))
+    return std::nullopt;
+
+  Intrinsic::ID IID;
+  switch ((II.getIntrinsicID())) {
+  case Intrinsic::aarch64_sve_cmpne:
+    IID = Intrinsic::aarch64_sve_cmpeq;
+    break;
+  case Intrinsic::aarch64_sve_cmpne_wide:
+    IID = Intrinsic::aarch64_sve_cmpeq_wide;
----------------
paulwalker-arm wrote:

I'm happy to defer the work, but presumably this transformation is applicable across all integer comparisons?

https://github.com/llvm/llvm-project/pull/207007