[llvm] [llvm][GISel] Use computeKnownFPClass (PR #141484)

[Matt Arsenault via llvm-commits]

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@@ -84,7 +85,9 @@ define float @test_fmed3_maybe_SNaN_input_zero_third_operand_ieee_true_dx10clamp
 ; GFX12-NEXT:    s_wait_samplecnt 0x0
 ; GFX12-NEXT:    s_wait_bvhcnt 0x0
 ; GFX12-NEXT:    s_wait_kmcnt 0x0
-; GFX12-NEXT:    v_mul_f32_e64 v0, v0, 2.0 clamp
+; GFX12-NEXT:    v_mul_f32_e32 v0, 2.0, v0
+; GFX12-NEXT:    s_delay_alu instid0(VALU_DEP_1)
+; GFX12-NEXT:    v_med3_num_f32 v0, v0, 1.0, 0
 ; GFX12-NEXT:    s_setpc_b64 s[30:31]
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arsenm wrote:

Regression 

https://github.com/llvm/llvm-project/pull/141484