[llvm] [AMDGPU] Add verifier for flat_scr_base_hi read hazard (PR #170550)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: Stanislav Mekhanoshin (rampitec)

<details>
<summary>Changes</summary>

Also excludes S_MOV_B64 from the prohibited instructions as
this is not required by the original ticket. We cannot fold
it though anyway because of the RC mismatch, but we have some
mir tests with such use.


---
Full diff: https://github.com/llvm/llvm-project/pull/170550.diff


2 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/SIInstrInfo.cpp (+14-1) 
- (added) llvm/test/MachineVerifier/AMDGPU/hazard-gfx1250-flat-src-hi.mir (+66) 


``````````diff
diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
index 7535407741f1f..3943560078ce2 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -5808,6 +5808,18 @@ bool SIInstrInfo::verifyInstruction(const MachineInstr &MI,
     }
   }
 
+  if (ST.hasFlatScratchHiInB64InstHazard() && isSALU(MI) &&
+      MI.readsRegister(AMDGPU::SRC_FLAT_SCRATCH_BASE_HI, &RI) &&
+      Opcode != AMDGPU::S_MOV_B64) {
+    const MachineOperand *Dst = getNamedOperand(MI, AMDGPU::OpName::sdst);
+    if ((Dst && AMDGPU::getRegBitWidth(
+                    *RI.getRegClassForReg(MRI, Dst->getReg())) == 64) ||
+        Opcode == AMDGPU::S_BITCMP0_B64 || Opcode == AMDGPU::S_BITCMP1_B64) {
+      ErrInfo = "Instruction cannot read flat_scratch_base_hi";
+      return false;
+    }
+  }
+
   return true;
 }
 
@@ -6259,7 +6271,8 @@ bool SIInstrInfo::isLegalRegOperand(const MachineInstr &MI, unsigned OpIdx,
     return false;
 
   if (ST.hasFlatScratchHiInB64InstHazard() &&
-      MO.getReg() == AMDGPU::SRC_FLAT_SCRATCH_BASE_HI && isSALU(MI)) {
+      MO.getReg() == AMDGPU::SRC_FLAT_SCRATCH_BASE_HI && isSALU(MI) &&
+      Opc != AMDGPU::S_MOV_B64) {
     if (const MachineOperand *Dst = getNamedOperand(MI, AMDGPU::OpName::sdst)) {
       if (AMDGPU::getRegBitWidth(*RI.getRegClassForReg(MRI, Dst->getReg())) ==
           64)
diff --git a/llvm/test/MachineVerifier/AMDGPU/hazard-gfx1250-flat-src-hi.mir b/llvm/test/MachineVerifier/AMDGPU/hazard-gfx1250-flat-src-hi.mir
new file mode 100644
index 0000000000000..3b9b40c52d1ed
--- /dev/null
+++ b/llvm/test/MachineVerifier/AMDGPU/hazard-gfx1250-flat-src-hi.mir
@@ -0,0 +1,66 @@
+# RUN: not --crash llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx1250 -verify-machineinstrs -run-pass=none -filetype=null %s 2>&1 | FileCheck %s
+
+---
+name:            salu_64_bit_inst_reads_flat_scratch_base_hi
+tracksRegLiveness: true
+body:             |
+  bb.0:
+
+    %0:sreg_64 = IMPLICIT_DEF
+    $sgpr0_sgpr1 = IMPLICIT_DEF
+
+    ; CHECK: *** Bad machine code: Instruction cannot read flat_scratch_base_hi ***
+    ; CHECK: S_ASHR_I64
+
+    %1:sreg_64 = S_ASHR_I64 %0:sreg_64, $src_flat_scratch_base_hi, implicit-def $scc
+
+    ; CHECK: *** Bad machine code: Instruction cannot read flat_scratch_base_hi ***
+    ; CHECK: S_LSHL_B64
+
+    %2:sreg_64 = S_LSHL_B64 %0:sreg_64, $src_flat_scratch_base_hi, implicit-def $scc
+
+    ; CHECK: *** Bad machine code: Instruction cannot read flat_scratch_base_hi ***
+    ; CHECK: S_LSHR_B64
+
+    %3:sreg_64 = S_LSHR_B64 %0:sreg_64, $src_flat_scratch_base_hi, implicit-def $scc
+
+    ; CHECK: *** Bad machine code: Instruction cannot read flat_scratch_base_hi ***
+    ; CHECK: S_BFE_I64
+
+    %4:sreg_64 = S_BFE_I64 %0:sreg_64, $src_flat_scratch_base_hi, implicit-def $scc
+
+    ; CHECK: *** Bad machine code: Instruction cannot read flat_scratch_base_hi ***
+    ; CHECK: S_BFE_U64
+
+    %5:sreg_64 = S_BFE_U64 %0:sreg_64, $src_flat_scratch_base_hi, implicit-def $scc
+
+    ; CHECK: *** Bad machine code: Instruction cannot read flat_scratch_base_hi ***
+    ; CHECK: S_BFM_B64
+
+    %6:sreg_64 = S_BFM_B64 $src_flat_scratch_base_hi, 1, implicit-def $scc
+
+    ; CHECK: *** Bad machine code: Instruction cannot read flat_scratch_base_hi ***
+    ; CHECK: S_BITCMP0_B64
+
+    S_BITCMP0_B64 %0:sreg_64, $src_flat_scratch_base_hi, implicit $scc, implicit-def $scc
+
+    ; CHECK: *** Bad machine code: Instruction cannot read flat_scratch_base_hi ***
+    ; CHECK: S_BITCMP1_B64
+
+    S_BITCMP1_B64 %0:sreg_64, $src_flat_scratch_base_hi, implicit $scc, implicit-def $scc
+
+    ; CHECK: *** Bad machine code: Instruction cannot read flat_scratch_base_hi ***
+    ; CHECK: S_BITREPLICATE_B64_B32
+
+    %7:sreg_64 = S_BITREPLICATE_B64_B32 $src_flat_scratch_base_hi, implicit-def $scc
+
+    ; CHECK: *** Bad machine code: Instruction cannot read flat_scratch_base_hi ***
+    ; CHECK: S_BITSET0_B64
+
+    $sgpr0_sgpr1 = S_BITSET0_B64 $src_flat_scratch_base_hi, $sgpr0_sgpr1, implicit-def $scc
+
+    ; CHECK: *** Bad machine code: Instruction cannot read flat_scratch_base_hi ***
+    ; CHECK: S_BITSET1_B64
+
+    $sgpr0_sgpr1 = S_BITSET1_B64 $src_flat_scratch_base_hi, $sgpr0_sgpr1, implicit-def $scc
+...

``````````

</details>


https://github.com/llvm/llvm-project/pull/170550