[llvm] [AMDGPU][GlobalISel] Improve combining on v_ldexp (PR #190236)

[Petar Avramovic via llvm-commits]

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@@ -71,34 +57,19 @@ define amdgpu_cs half @v_s_amdgcn_exp_f16(half inreg %src) {
 }
 
 define amdgpu_cs float @v_s_log_f32(float inreg %src) {
-; GFX12-SDAG-LABEL: v_s_log_f32:
-; GFX12-SDAG:       ; %bb.0:
-; GFX12-SDAG-NEXT:    s_cmp_lt_f32 s0, 0x800000
-; GFX12-SDAG-NEXT:    s_cselect_b32 s1, 0x4f800000, 1.0
-; GFX12-SDAG-NEXT:    s_delay_alu instid0(SALU_CYCLE_1) | instskip(SKIP_1) | instid1(SALU_CYCLE_2)
-; GFX12-SDAG-NEXT:    s_mul_f32 s0, s0, s1
-; GFX12-SDAG-NEXT:    s_cselect_b32 s1, 0x42000000, 0
-; GFX12-SDAG-NEXT:    v_s_log_f32 s0, s0
-; GFX12-SDAG-NEXT:    s_delay_alu instid0(TRANS32_DEP_1) | instskip(SKIP_1) | instid1(SALU_CYCLE_2)
-; GFX12-SDAG-NEXT:    s_sub_f32 s0, s0, s1
-; GFX12-SDAG-NEXT:    s_wait_alu depctr_sa_sdst(0)
-; GFX12-SDAG-NEXT:    v_mov_b32_e32 v0, s0
-; GFX12-SDAG-NEXT:    ; return to shader part epilog
-;
-; GFX12-GISEL-LABEL: v_s_log_f32:
-; GFX12-GISEL:       ; %bb.0:
-; GFX12-GISEL-NEXT:    s_cmp_lt_f32 s0, 0x800000
-; GFX12-GISEL-NEXT:    s_cselect_b32 s1, 1, 0
-; GFX12-GISEL-NEXT:    s_delay_alu instid0(SALU_CYCLE_1) | instskip(SKIP_3) | instid1(VALU_DEP_1)
-; GFX12-GISEL-NEXT:    s_lshl_b32 s2, s1, 5
-; GFX12-GISEL-NEXT:    s_cmp_lg_u32 s1, 0
-; GFX12-GISEL-NEXT:    v_ldexp_f32 v0, s0, s2
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petar-avramovic wrote:

like here v_ldexp_f32 -> s_mul_f32

https://github.com/llvm/llvm-project/pull/190236