[llvm] [X86][GlobalIsel] support G_FABS for f80 (PR #136718)

[Evgenii Kudriashov via llvm-commits]

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@@ -466,6 +466,11 @@ X86LegalizerInfo::X86LegalizerInfo(const X86Subtarget &STI,
                (UseX87 && typeInSet(0, {s80})(Query));
       });
 
+  //TODO: f32 and f64 FABS require xmm support
+  getActionDefinitionsBuilder(G_FABS)
+      .legalFor(UseX87, {s8, s80})
+      .lower();
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e-kud wrote:

Does `lower` generate the selectable code? Then we probably can add tests for `float` and `double` as well.

https://github.com/llvm/llvm-project/pull/136718