[clang] [llvm] [ValueTracking] use KnownBits to compute fpclass from bitcast (PR #97762)

[Alex MacLean via cfe-commits]

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@@ -1549,30 +1549,10 @@ define amdgpu_kernel void @multiple_uses_fneg_select_f64(double %x, double %y, i
 define amdgpu_kernel void @fnge_select_f32_multi_use_regression(float %.i2369) {
 ; GCN-LABEL: fnge_select_f32_multi_use_regression:
 ; GCN:       ; %bb.0: ; %.entry
-; GCN-NEXT:    s_load_dword s0, s[4:5], 0x0
-; GCN-NEXT:    s_waitcnt lgkmcnt(0)
-; GCN-NEXT:    v_cmp_nlt_f32_e64 s[0:1], s0, 0
-; GCN-NEXT:    v_cndmask_b32_e64 v0, 0, 1, s[0:1]
-; GCN-NEXT:    v_cmp_ngt_f32_e32 vcc, 0, v0
-; GCN-NEXT:    v_cndmask_b32_e32 v1, 0, v0, vcc
-; GCN-NEXT:    v_mul_f32_e64 v0, -v0, v1
-; GCN-NEXT:    v_cmp_lt_f32_e32 vcc, 0, v0
-; GCN-NEXT:    s_and_b64 vcc, exec, vcc
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AlexMaclean wrote:

https://github.com/llvm/llvm-project/pull/106268 slightly adjusts this test to ensure it doesn't get DCE'd away after this change. 

https://github.com/llvm/llvm-project/pull/97762