[llvm] AMDGPU: Remove floating point dot4 and dot2 from gfx1250 support (PR #145751)

[Changpeng Fang via llvm-commits]

https://github.com/changpeng created https://github.com/llvm/llvm-project/pull/145751

   We have FeatureDot9Insts for dot2 and FeatureDot11Insts for dot4. And gfx1250 does not support these two features. So everything was in place except that we need to copy SubtargetPredicate from pseudo to real for VOP3_DPP8_t16.

>From 6f97d005e842545493163740efb133f3f28b954f Mon Sep 17 00:00:00 2001
From: Changpeng Fang <changpeng.fang at amd.com>
Date: Wed, 25 Jun 2025 10:54:57 -0700
Subject: [PATCH] AMDGPU: Remove floating point dot4 and dot2 from gfx1250
 support

   We have FeatureDot9Insts for dot2 and FeatureDot11Insts for dot4.
And gfx1250 does not support these two features. So everthing was in
place except that we need to copy SubtargetPredicate from pseudo to
real for VOP3_DPP8_t16.
---
 llvm/lib/Target/AMDGPU/VOPInstructions.td     |  1 +
 llvm/test/MC/AMDGPU/gfx1250_asm_unsupported.s | 62 +++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/llvm/lib/Target/AMDGPU/VOPInstructions.td b/llvm/lib/Target/AMDGPU/VOPInstructions.td
index 0b64b504466c8..1e47acb5fde4f 100644
--- a/llvm/lib/Target/AMDGPU/VOPInstructions.td
+++ b/llvm/lib/Target/AMDGPU/VOPInstructions.td
@@ -1679,6 +1679,7 @@ class Base_VOP3_DPP8_t16<bits<10> op, VOP_Pseudo ps, string opName = ps.OpName>
   let SchedRW = ps.SchedRW;
   let Uses = ps.Uses;
 
+  let SubtargetPredicate = ps.SubtargetPredicate;
   let OtherPredicates = ps.OtherPredicates;
   let True16Predicate = ps.True16Predicate;
 }
diff --git a/llvm/test/MC/AMDGPU/gfx1250_asm_unsupported.s b/llvm/test/MC/AMDGPU/gfx1250_asm_unsupported.s
index 55cb9dab3c048..2111e91cd5ef2 100644
--- a/llvm/test/MC/AMDGPU/gfx1250_asm_unsupported.s
+++ b/llvm/test/MC/AMDGPU/gfx1250_asm_unsupported.s
@@ -1,5 +1,67 @@
 ; RUN: not llvm-mc -triple=amdgcn -mcpu=gfx1250 -show-encoding %s 2>&1 | FileCheck --check-prefix=GFX1250-ERR --implicit-check-not=error: --strict-whitespace %s
 
+;; DOT4_F32_*, DOT2_F32_*, DOT2_F16 and DOT2_BF16
+
+v_dot4_f32_fp8_fp8 v0, v1, v2, v3
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot4_f32_fp8_fp8 v0, v1, v2, v3 row_mirror
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot4_f32_fp8_fp8 v0, v1, v2, v3 dpp8:[0,1,2,3,4,5,6,7]
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot4_f32_fp8_bf8 v0, v1, v2, v3
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot4_f32_fp8_bf8 v0, v1, v2, v3 quad_perm:[3,2,1,0]
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot4_f32_fp8_bf8 v0, v1, v2, v3 dpp8:[0,1,2,3,4,5,6,7]
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot4_f32_bf8_fp8 v0, v1, v2, v3
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot4_f32_bf8_fp8 v0, v1, v2, v3 row_shl:15
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot4_f32_bf8_fp8 v0, v1, v2, v3 dpp8:[0,1,2,3,4,5,6,7]
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot4_f32_bf8_bf8 v0, v1, v2, v3
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot4_f32_bf8_bf8 v0, v1, v2, v3 row_share:15
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot4_f32_bf8_bf8 v0, v1, v2, v3 dpp8:[0,1,2,3,4,5,6,7]
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot2_f16_f16 v5, v1, v2, s3
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot2_f16_f16_e64_dpp v0, v1, v2, v3 quad_perm:[0,1,2,3] row_mask:0x0 bank_mask:0x0 fi:1
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot2_f16_f16_e64_dpp v0, v1, v2, v3 dpp8:[0,1,2,3,4,4,4,4]
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot2_bf16_bf16 v5, v1, v2, s3
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot2_bf16_bf16_e64_dpp v0, v1, v2, v3 quad_perm:[0,1,2,3] row_mask:0x0 bank_mask:0x0 fi:1
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot2_bf16_bf16_e64_dpp v0, v1, v2, v3 dpp8:[0,1,2,3,4,4,4,4]
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot2_f32_bf16 v5, v1, v2, v3
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+v_dot2_f32_f16 v5, v1, v2, s3
+// GFX1250-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
 ;; LDS-direct and parameter-load, VINTERP
 
 ds_direct_load v1 wait_va_vdst:15