[llvm] [AMDGPU][MC][True16] VOP3dot instruction update for true16/fake16 (PR #113474)

[Joe Nash via llvm-commits]

================
@@ -3395,32 +3395,92 @@
 # W64-FAKE16: v_sub_nc_u16_e64_dpp v255, v255, v255 op_sel:[0,0,1] clamp dpp8:[0,0,0,0,0,0,0,0] fi:1 ; encoding: [0xff,0xc0,0x04,0xd7,0xea,0xfe,0x03,0x00,0xff,0x00,0x00,0x00]
 0xff,0xc0,0x04,0xd7,0xea,0xfe,0x03,0x00,0xff,0x00,0x00,0x00
 
-# GFX12: v_dot2_f16_f16_e64_dpp v0, v1, v2, v3 dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x00,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W32-REAL16: v_dot2_f16_f16_e64_dpp v0.l, v1, v2, v3.l dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x00,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W32-FAKE16: v_dot2_f16_f16_e64_dpp v0, v1, v2, v3 dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x00,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W64-REAL16: v_dot2_f16_f16_e64_dpp v0.l, v1, v2, v3.l dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x00,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W64-FAKE16: v_dot2_f16_f16_e64_dpp v0, v1, v2, v3 dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x00,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
 0x00,0x00,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92
 
-# op_sel[1:0] are ignored
-# GFX12: v_dot2_f16_f16_e64_dpp v0, v1, v2, v3 op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x60,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W32-REAL16: v_dot2_f16_f16_e64_dpp v0.h, v1, v2, v3.h op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x60,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W32-FAKE16: v_dot2_f16_f16_e64_dpp v0, v1, v2, v3 op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x60,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W64-REAL16: v_dot2_f16_f16_e64_dpp v0.h, v1, v2, v3.h op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x60,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W64-FAKE16: v_dot2_f16_f16_e64_dpp v0, v1, v2, v3 op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x60,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
 0x00,0x78,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92
 
-# GFX12: v_dot2_f16_f16_e64_dpp v0, v1, v2, v3 op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x60,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W32-REAL16: v_dot2_f16_f16_e64_dpp v0.h, v1, v2, v3.h op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x60,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W32-FAKE16: v_dot2_f16_f16_e64_dpp v0, v1, v2, v3 op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x60,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W64-REAL16: v_dot2_f16_f16_e64_dpp v0.h, v1, v2, v3.h op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x60,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
+# W64-FAKE16: v_dot2_f16_f16_e64_dpp v0, v1, v2, v3 op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x60,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
 0x00,0x60,0x66,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92
 
-# GFX12: v_dot2_f16_f16_e64_dpp v0, |v1|, -v2, -|s3| op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x65,0x66,0xd6,0xe9,0x04,0x0e,0xc0,0x01,0x88,0x46,0x92]
+# W32-REAL16: v_dot2_f16_f16_e64_dpp v0.h, |v1|, -v2, -|s3| op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x65,0x66,0xd6,0xe9,0x04,0x0e,0xc0,0x01,0x88,0x46,0x92]
+# W32-FAKE16: v_dot2_f16_f16_e64_dpp v0, |v1|, -v2, -|s3| op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x65,0x66,0xd6,0xe9,0x04,0x0e,0xc0,0x01,0x88,0x46,0x92]
+# W64-REAL16: v_dot2_f16_f16_e64_dpp v0.h, |v1|, -v2, -|s3| op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x65,0x66,0xd6,0xe9,0x04,0x0e,0xc0,0x01,0x88,0x46,0x92]
+# W64-FAKE16: v_dot2_f16_f16_e64_dpp v0, |v1|, -v2, -|s3| op_sel:[0,0,1,1] dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x65,0x66,0xd6,0xe9,0x04,0x0e,0xc0,0x01,0x88,0x46,0x92]
 0x00,0x65,0x66,0xd6,0xe9,0x04,0x0e,0xc0,0x01,0x88,0x46,0x92
 
-# GFX12: v_dot2_bf16_bf16_e64_dpp v0, v1, v2, v3 dpp8:[0,1,2,3,4,4,4,4] ; encoding: [0x00,0x00,0x67,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92]
-0x00,0x00,0x67,0xd6,0xe9,0x04,0x0e,0x04,0x01,0x88,0x46,0x92
+# W32-REAL16: v_dot2_f16_f16_e64_dpp v5.l, v1, v2, v255.h op_sel:[0,0,1,0] dpp8:[7,6,5,4,3,2,1,0] ; encoding: [0x05,0x20,0x66,0xd6,0xe9,0x04,0xfe,0x07,0x01,0x77,0x39,0x05]
+# W32-FAKE16: v_dot2_f16_f16_e64_dpp v5, v1, v2, v255 op_sel:[0,0,1,0] dpp8:[7,6,5,4,3,2,1,0] ; encoding: [0x05,0x20,0x66,0xd6,0xe9,0x04,0xfe,0x07,0x01,0x77,0x39,0x05]
+# W64-REAL16: v_dot2_f16_f16_e64_dpp v5.l, v1, v2, v255.h op_sel:[0,0,1,0] dpp8:[7,6,5,4,3,2,1,0] ; encoding: [0x05,0x20,0x66,0xd6,0xe9,0x04,0xfe,0x07,0x01,0x77,0x39,0x05]
+# W64-FAKE16: v_dot2_f16_f16_e64_dpp v5, v1, v2, v255 op_sel:[0,0,1,0] dpp8:[7,6,5,4,3,2,1,0] ; encoding: [0x05,0x20,0x66,0xd6,0xe9,0x04,0xfe,0x07,0x01,0x77,0x39,0x05]
+0x05,0x20,0x66,0xd6,0xe9,0x04,0xfe,0x07,0x01,0x77,0x39,0x05
+
+# W32-REAL16: v_dot2_f16_f16_e64_dpp v255.h, -|v255|, -|v255|, -|src_scc| op_sel:[0,0,0,1] dpp8:[0,0,0,0,0,0,0,0] fi:1 ; encoding: [0xff,0x47,0x66,0xd6,0xea,0xfe,0xf7,0xe3,0xff,0x00,0x00,0x00]
+# W32-FAKE16: v_dot2_f16_f16_e64_dpp v255, -|v255|, -|v255|, -|src_scc| op_sel:[0,0,0,1] dpp8:[0,0,0,0,0,0,0,0] fi:1 ; encoding: [0xff,0x47,0x66,0xd6,0xea,0xfe,0xf7,0xe3,0xff,0x00,0x00,0x00]
+# W64-REAL16: v_dot2_f16_f16_e64_dpp v255.h, -|v255|, -|v255|, -|src_scc| op_sel:[0,0,0,1] dpp8:[0,0,0,0,0,0,0,0] fi:1 ; encoding: [0xff,0x47,0x66,0xd6,0xea,0xfe,0xf7,0xe3,0xff,0x00,0x00,0x00]
+# W64-FAKE16: v_dot2_f16_f16_e64_dpp v255, -|v255|, -|v255|, -|src_scc| op_sel:[0,0,0,1] dpp8:[0,0,0,0,0,0,0,0] fi:1 ; encoding: [0xff,0x47,0x66,0xd6,0xea,0xfe,0xf7,0xe3,0xff,0x00,0x00,0x00]
+0xff,0x47,0x66,0xd6,0xea,0xfe,0xf7,0xe3,0xff,0x00,0x00,0x00
+
+# GFX11: v_dot2_f16_f16_e64_dpp v5.l, v1, v2, v255.h op_sel:[0,0,1,0] dpp8:[7,6,5,4,3,2,1,0] ; encoding: [0x05,0x20,0x66,0xd6,0xe9,0x04,0xfe,0x07,0x01,0x77,0x39,0x05]
+0x05,0x20,0x66,0xd6,0xe9,0x04,0xfe,0x07,0x01,0x77,0x39,0x05
+
+# GFX11: v_dot2_f16_f16_e64_dpp v255.h, -|v255|, -|v255|, -|src_scc| op_sel:[0,0,0,1] dpp8:[0,0,0,0,0,0,0,0] fi:1 ; encoding: [0xff,0x47,0x66,0xd6,0xea,0xfe,0xf7,0xe3,0xff,0x00,0x00,0x00]
+0xff,0x47,0x66,0xd6,0xea,0xfe,0xf7,0xe3,0xff,0x00,0x00,0x00
 
 # op_sel[1:0] are ignored
----------------
Sisyph wrote:

The comment refers to the actual semantics of the instructions, in that the opsel bit for src0 and src1 is ignored by hardware. And we can see from the test those opsel bits are also stripped out by the disassembler. The input bytes set those bits, and the output disassembly does not set them. Yes this is a problem for round tripping. It looks like a problem with the script moving comments around, and they should be put back on the instructions they pertain to (it looks like those where the second byte of input is 0x78).

https://github.com/llvm/llvm-project/pull/113474