[llvm] [AArch64] Put legal action first for G_ATOMIC_CMPXCHG (PR #74613)

[Thomas Preud'homme via llvm-commits]

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@@ -758,11 +758,11 @@ AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST)
           all(typeInSet(0, {s8, s16, s32, s64, s128}), typeIs(2, p0)));
 
   getActionDefinitionsBuilder(G_ATOMIC_CMPXCHG)
+      .clampScalar(0, s32, s128)
+      .legalIf(all(typeInSet(0, {s32, s64}), typeIs(1, p0)))
       .customIf([](const LegalityQuery &Query) {
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RoboTux wrote:

As pointed by Pavel, typeIs(0, s128) is not the same as testing that the size in bits is 128 due to vector. Although the intent is probably to former, keeping the existing check makes this more of an NFC.

https://github.com/llvm/llvm-project/pull/74613