[llvm] [AMDGPU] Update cost model gfx950 min/max tests. NFC. (PR #139310)

[Matt Arsenault via llvm-commits]

================
@@ -35,6 +36,15 @@ define void @maximum_f16() {
 ; SLOWF64-NEXT:  Cost Model: Found an estimated cost of 176 for instruction: %v16f16 = call <16 x half> @llvm.maximum.v16f16(<16 x half> undef, <16 x half> undef)
 ; SLOWF64-NEXT:  Cost Model: Found an estimated cost of 10 for instruction: ret void
 ;
+; GFX950-SIZE-LABEL: 'maximum_f16'
+; GFX950-SIZE-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %f16 = call half @llvm.maximum.f16(half undef, half undef)
+; GFX950-SIZE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v2f16 = call <2 x half> @llvm.maximum.v2f16(<2 x half> undef, <2 x half> undef)
+; GFX950-SIZE-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v3f16 = call <3 x half> @llvm.maximum.v3f16(<3 x half> undef, <3 x half> undef)
+; GFX950-SIZE-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v4f16 = call <4 x half> @llvm.maximum.v4f16(<4 x half> undef, <4 x half> undef)
+; GFX950-SIZE-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v8f16 = call <8 x half> @llvm.maximum.v8f16(<8 x half> undef, <8 x half> undef)
+; GFX950-SIZE-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v16f16 = call <16 x half> @llvm.maximum.v16f16(<16 x half> undef, <16 x half> undef)
----------------
arsenm wrote:

These values look broken. 1 element is more expensive than 2, and every other vector size is also size 2 

https://github.com/llvm/llvm-project/pull/139310