[llvm] [AMDGPU] Add some more GFX12 test coverage (PR #120581)

[Jay Foad via llvm-commits]

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@@ -3766,3 +3766,69 @@ define <2 x double> @v_no_fmaximum3_f64__multi_use(double %a, double %b, double
   %insert.1 = insertelement <2 x double> %insert.0, double %max1, i32 1
   ret <2 x double> %insert.1
 }
+
+; Checks whether the test passes; performMinMaxCombine() should not optimize vector patterns of maximum3
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jayfoad wrote:

Good point. This had been removed upstream but for some reason lived on in our downstream branch.

https://github.com/llvm/llvm-project/pull/120581