[llvm] [AMDGPU] Remove s_cmpk_* for GFX12 (PR #75497)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: Jay Foad (jayfoad)

<details>
<summary>Changes</summary>

No GFX12 encoding was added for these. This patch adds tests that they
are not recognized by the assembler and defends against generating them
in codegen.


---
Full diff: https://github.com/llvm/llvm-project/pull/75497.diff


3 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/GCNSubtarget.h (+3) 
- (modified) llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp (+3) 
- (modified) llvm/test/MC/AMDGPU/gfx12_unsupported.s (+36) 


``````````diff
diff --git a/llvm/lib/Target/AMDGPU/GCNSubtarget.h b/llvm/lib/Target/AMDGPU/GCNSubtarget.h
index 8e1350be8b45fc..f017b809dae620 100644
--- a/llvm/lib/Target/AMDGPU/GCNSubtarget.h
+++ b/llvm/lib/Target/AMDGPU/GCNSubtarget.h
@@ -830,6 +830,9 @@ class GCNSubtarget final : public AMDGPUGenSubtargetInfo,
 
   bool hasInstPrefetch() const { return getGeneration() >= GFX10; }
 
+  // Has s_cmpk_* instructions.
+  bool hasSCmpK() const { return getGeneration() < GFX12; }
+
   // Scratch is allocated in 256 dword per wave blocks for the entire
   // wavefront. When viewed from the perspective of an arbitrary workitem, this
   // is 4-byte aligned.
diff --git a/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp b/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
index 856121be78031d..d290dd82b76058 100644
--- a/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
+++ b/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
@@ -211,6 +211,9 @@ void SIShrinkInstructions::copyExtraImplicitOps(MachineInstr &NewMI,
 }
 
 void SIShrinkInstructions::shrinkScalarCompare(MachineInstr &MI) const {
+  if (!ST->hasSCmpK())
+    return;
+
   // cmpk instructions do scc = dst <cc op> imm16, so commute the instruction to
   // get constants on the RHS.
   if (!MI.getOperand(0).isReg())
diff --git a/llvm/test/MC/AMDGPU/gfx12_unsupported.s b/llvm/test/MC/AMDGPU/gfx12_unsupported.s
index e835710a69fe85..7e455d1d83a3d4 100644
--- a/llvm/test/MC/AMDGPU/gfx12_unsupported.s
+++ b/llvm/test/MC/AMDGPU/gfx12_unsupported.s
@@ -31,6 +31,42 @@ ds_sub_gs_reg_rtn v[0:1], v2 gds
 ds_wrap_rtn_b32 v0, v1, v2, v3
 // CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
 
+s_cmpk_eq_i32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_cmpk_lg_i32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_cmpk_gt_i32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_cmpk_ge_i32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_cmpk_lt_i32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_cmpk_le_i32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_cmpk_eq_u32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_cmpk_lg_u32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_cmpk_gt_u32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_cmpk_ge_u32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_cmpk_lt_u32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_cmpk_le_u32 s0, 0
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
 ds_gws_sema_release_all gds
 // CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/75497