[llvm] [AMDGPU] Extend zero initialization of return values for TFE (PR #85759)

[Jay Foad via llvm-commits]

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@@ -22,18 +22,36 @@ main_body:
 define amdgpu_ps <4 x float> @load_2dmsaa_both(<8 x i32> inreg %rsrc, ptr addrspace(1) inreg %out, i32 %s, i32 %t, i32 %fragid) {
 ; GFX11-LABEL: load_2dmsaa_both:
 ; GFX11:       ; %bb.0: ; %main_body
-; GFX11-NEXT:    image_msaa_load v[0:4], v[0:2], s[0:7] dmask:0x2 dim:SQ_RSRC_IMG_2D_MSAA unorm tfe lwe ; encoding: [0x98,0x02,0x60,0xf0,0x00,0x00,0x60,0x00]
-; GFX11-NEXT:    v_mov_b32_e32 v5, 0 ; encoding: [0x80,0x02,0x0a,0x7e]
+; GFX11-NEXT:    v_dual_mov_b32 v5, v0 :: v_dual_mov_b32 v8, 0 ; encoding: [0x00,0x01,0x10,0xca,0x80,0x00,0x08,0x05]
+; GFX11-NEXT:    v_dual_mov_b32 v7, v2 :: v_dual_mov_b32 v6, v1 ; encoding: [0x02,0x01,0x10,0xca,0x01,0x01,0x06,0x07]
+; GFX11-NEXT:    s_delay_alu instid0(VALU_DEP_2) | instskip(SKIP_3) | instid1(VALU_DEP_4) ; encoding: [0x42,0x02,0x87,0xbf]
+; GFX11-NEXT:    v_mov_b32_e32 v9, v8 ; encoding: [0x08,0x03,0x12,0x7e]
+; GFX11-NEXT:    v_mov_b32_e32 v10, v8 ; encoding: [0x08,0x03,0x14,0x7e]
+; GFX11-NEXT:    v_mov_b32_e32 v11, v8 ; encoding: [0x08,0x03,0x16,0x7e]
+; GFX11-NEXT:    v_mov_b32_e32 v12, v8 ; encoding: [0x08,0x03,0x18,0x7e]
+; GFX11-NEXT:    v_dual_mov_b32 v0, v8 :: v_dual_mov_b32 v1, v9 ; encoding: [0x08,0x01,0x10,0xca,0x09,0x01,0x00,0x00]
+; GFX11-NEXT:    s_delay_alu instid0(VALU_DEP_3) | instskip(NEXT) | instid1(VALU_DEP_3) ; encoding: [0x93,0x01,0x87,0xbf]
+; GFX11-NEXT:    v_dual_mov_b32 v2, v10 :: v_dual_mov_b32 v3, v11 ; encoding: [0x0a,0x01,0x10,0xca,0x0b,0x01,0x02,0x02]
+; GFX11-NEXT:    v_mov_b32_e32 v4, v12 ; encoding: [0x0c,0x03,0x08,0x7e]
+; GFX11-NEXT:    image_msaa_load v[0:4], v[5:7], s[0:7] dmask:0x2 dim:SQ_RSRC_IMG_2D_MSAA unorm tfe lwe ; encoding: [0x98,0x02,0x60,0xf0,0x05,0x00,0x60,0x00]
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jayfoad wrote:

Not your fault, but this code is terrible. It's zeroing v[8:12] and then copying that into v[0:4].

https://github.com/llvm/llvm-project/pull/85759