[llvm] [AMDGPU] Fix crash due to assertion failure (PR #123627)

Chinmay Deshpande via llvm-commits llvm-commits at lists.llvm.org
Tue Jan 21 04:35:32 PST 2025


https://github.com/chinmaydd updated https://github.com/llvm/llvm-project/pull/123627

>From 741b26037cd949df395ecd35a4d46fe79653488d Mon Sep 17 00:00:00 2001
From: Chinmay Deshpande <ChinmayDiwakar.Deshpande at amd.com>
Date: Mon, 20 Jan 2025 09:28:13 -0500
Subject: [PATCH 1/2] [AMDGPU] Fix crash due to assertion failure

Add check for FLAT instructions that dont use vector registers when computing VALU hazard.

Change-Id: I558aed17b109047bdc64f8a7e5f419d4d37577cf
---
 .../lib/Target/AMDGPU/GCNHazardRecognizer.cpp |  9 ++-
 .../CodeGen/AMDGPU/fix-crash-valu-hazard.ll   | 67 +++++++++++++++++++
 llvm/test/CodeGen/AMDGPU/hazards-gfx950.mir   | 18 +++++
 3 files changed, 91 insertions(+), 3 deletions(-)
 create mode 100644 llvm/test/CodeGen/AMDGPU/fix-crash-valu-hazard.ll

diff --git a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
index 6baef137df5e16..873d18e30a430a 100644
--- a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
@@ -858,9 +858,12 @@ int GCNHazardRecognizer::createsVALUHazard(const MachineInstr &MI) {
   }
 
   if (TII->isFLAT(MI)) {
-    int DataIdx = AMDGPU::getNamedOperandIdx(Opcode, AMDGPU::OpName::vdata);
-    if (AMDGPU::getRegBitWidth(Desc.operands()[DataIdx].RegClass) > 64)
-      return DataIdx;
+    // There is no hazard if the instruction does not use vector regs
+    if (VDataIdx == -1)
+      return -1;
+
+    if (AMDGPU::getRegBitWidth(VDataRCID) > 64)
+      return VDataIdx;
   }
 
   return -1;
diff --git a/llvm/test/CodeGen/AMDGPU/fix-crash-valu-hazard.ll b/llvm/test/CodeGen/AMDGPU/fix-crash-valu-hazard.ll
new file mode 100644
index 00000000000000..87811968c78711
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/fix-crash-valu-hazard.ll
@@ -0,0 +1,67 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=amdgcn -mcpu=gfx942 < %s | FileCheck -check-prefix=GFX942 %s
+; RUN: llc -mtriple=amdgcn -mcpu=gfx90a -O0 < %s | FileCheck -check-prefix=GFX90A %s
+
+ at G = addrspace(1) global <2 x i32> splat (i32 5)
+
+define amdgpu_ps void @global_load_lds_dword_saddr(ptr addrspace(1) inreg nocapture %gptr, ptr addrspace(3) nocapture %lptr) {
+; GFX942-LABEL: global_load_lds_dword_saddr:
+; GFX942:       ; %bb.0: ; %main_body
+; GFX942-NEXT:    v_readfirstlane_b32 s2, v0
+; GFX942-NEXT:    v_mov_b32_e32 v2, 0
+; GFX942-NEXT:    s_mov_b32 m0, s2
+; GFX942-NEXT:    s_nop 0
+; GFX942-NEXT:    global_load_lds_dword v2, s[0:1] offset:32 nt
+; GFX942-NEXT:    s_getpc_b64 s[0:1]
+; GFX942-NEXT:    s_add_u32 s0, s0, G at gotpcrel32@lo+4
+; GFX942-NEXT:    s_addc_u32 s1, s1, G at gotpcrel32@hi+12
+; GFX942-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x0
+; GFX942-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX942-NEXT:    s_load_dwordx2 s[2:3], s[0:1], 0x0
+; GFX942-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX942-NEXT:    s_mul_i32 s3, s3, 10
+; GFX942-NEXT:    s_mul_i32 s2, s2, 10
+; GFX942-NEXT:    v_mov_b32_e32 v0, s2
+; GFX942-NEXT:    v_mov_b32_e32 v1, s3
+; GFX942-NEXT:    global_store_dwordx2 v2, v[0:1], s[0:1]
+; GFX942-NEXT:    s_endpgm
+;
+; GFX90A-LABEL: global_load_lds_dword_saddr:
+; GFX90A:       ; %bb.0: ; %main_body
+; GFX90A-NEXT:    v_mov_b32_e32 v1, v0
+; GFX90A-NEXT:    s_mov_b32 s2, s0
+; GFX90A-NEXT:    ; kill: def $sgpr2 killed $sgpr2 def $sgpr2_sgpr3
+; GFX90A-NEXT:    s_mov_b32 s3, s1
+; GFX90A-NEXT:    ; kill: def $sgpr0_sgpr1 killed $sgpr2_sgpr3
+; GFX90A-NEXT:    s_getpc_b64 s[0:1]
+; GFX90A-NEXT:    s_add_u32 s0, s0, G at gotpcrel32@lo+4
+; GFX90A-NEXT:    s_addc_u32 s1, s1, G at gotpcrel32@hi+12
+; GFX90A-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    s_load_dwordx2 s[8:9], s[0:1], 0x0
+; GFX90A-NEXT:    v_mov_b32_e32 v0, 0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    s_mov_b32 s4, s9
+; GFX90A-NEXT:    s_mov_b32 s6, 10
+; GFX90A-NEXT:    s_mul_i32 s4, s4, s6
+; GFX90A-NEXT:    s_mov_b32 s5, s8
+; GFX90A-NEXT:    s_mul_i32 s5, s5, s6
+; GFX90A-NEXT:    v_mov_b32_e32 v2, s5
+; GFX90A-NEXT:    v_mov_b32_e32 v4, s4
+; GFX90A-NEXT:    ; kill: def $vgpr2 killed $vgpr2 def $vgpr2_vgpr3 killed $exec
+; GFX90A-NEXT:    v_mov_b32_e32 v3, v4
+; GFX90A-NEXT:    ; implicit-def: $sgpr4
+; GFX90A-NEXT:    v_readfirstlane_b32 s4, v1
+; GFX90A-NEXT:    s_mov_b32 m0, s4
+; GFX90A-NEXT:    s_nop 0
+; GFX90A-NEXT:    global_load_dword v0, s[2:3] offset:32 slc lds
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    global_store_dwordx2 v0, v[2:3], s[0:1]
+; GFX90A-NEXT:    s_endpgm
+main_body:
+  %LGV = load <2 x i32>, ptr addrspace(1) @G, align 8
+  %B = mul <2 x i32> %LGV, splat (i32 10)
+  call void @llvm.amdgcn.global.load.lds(ptr addrspace(1) %gptr, ptr addrspace(3) %lptr, i32 4, i32 32, i32 2)
+  store <2 x i32> %B, ptr addrspace(1) @G, align 8
+  ret void
+}
diff --git a/llvm/test/CodeGen/AMDGPU/hazards-gfx950.mir b/llvm/test/CodeGen/AMDGPU/hazards-gfx950.mir
index 49576433ab54da..d50442a7cd4bdf 100644
--- a/llvm/test/CodeGen/AMDGPU/hazards-gfx950.mir
+++ b/llvm/test/CodeGen/AMDGPU/hazards-gfx950.mir
@@ -1223,3 +1223,21 @@ body:             |
     early-clobber renamable $vgpr2 = V_CVT_SCALEF32_SR_PK_FP4_F16_e64 8, killed $vgpr0, 0, killed $vgpr3, 4, killed $vgpr1, killed $vgpr1, 0, implicit $mode, implicit $exec
     S_SETPC_B64_return undef $sgpr30_sgpr31, implicit killed $vgpr0
 ...
+
+---
+name:            test_flat_valu_hazard
+noVRegs:         true
+body:             |
+  bb.0:
+    liveins: $vgpr0, $vgpr1
+
+    ; GCN-LABEL: name: test_flat_valu_hazard
+    ; GCN: liveins: $vgpr0, $vgpr1
+    ; GCN-NEXT: {{  $}}
+    ; GCN-NEXT: GLOBAL_LOAD_LDS_DWORD_SADDR killed $sgpr0_sgpr1, killed $vgpr0, 32, 2, implicit $m0, implicit $exec
+    ; GCN-NEXT: $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec, implicit $exec
+    ; GCN-NEXT: FLAT_STORE_DWORDX2 killed renamable $vgpr2_vgpr3, killed renamable $vgpr0_vgpr1, 0, 0, implicit $exec, implicit $flat_scr
+    GLOBAL_LOAD_LDS_DWORD_SADDR killed $sgpr0_sgpr1, killed $vgpr0, 32, 2, implicit $m0, implicit $exec
+    $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec, implicit $exec
+    FLAT_STORE_DWORDX2 killed renamable $vgpr2_vgpr3, killed renamable $vgpr0_vgpr1, 0, 0, implicit $exec, implicit $flat_scr
+...

>From 85487392388ba0045df25b824e4ca11c2924f8f9 Mon Sep 17 00:00:00 2001
From: Chinmay Deshpande <ChinmayDiwakar.Deshpande at amd.com>
Date: Tue, 21 Jan 2025 07:35:13 -0500
Subject: [PATCH 2/2] [AMDGPU] Address review comments

Change-Id: I08607cabfdc2bf1018c03ffcca745b99c1f82174
---
 .../hazard-flat-instruction-valu-check.mir    | 20 +++++++++++++++++++
 llvm/test/CodeGen/AMDGPU/hazards-gfx950.mir   | 18 -----------------
 2 files changed, 20 insertions(+), 18 deletions(-)
 create mode 100644 llvm/test/CodeGen/AMDGPU/hazard-flat-instruction-valu-check.mir

diff --git a/llvm/test/CodeGen/AMDGPU/hazard-flat-instruction-valu-check.mir b/llvm/test/CodeGen/AMDGPU/hazard-flat-instruction-valu-check.mir
new file mode 100644
index 00000000000000..9a284258bc9f9f
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/hazard-flat-instruction-valu-check.mir
@@ -0,0 +1,20 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -mtriple=amdgcn -mcpu=gfx942 -verify-machineinstrs -run-pass=post-RA-hazard-rec %s -o - | FileCheck -check-prefix=GCN %s
+
+---
+name:            test_flat_valu_hazard
+noVRegs:         true
+body:             |
+  bb.0:
+    liveins: $vgpr0, $vgpr1
+
+    ; GCN-LABEL: name: test_flat_valu_hazard
+    ; GCN: liveins: $vgpr0, $vgpr1
+    ; GCN-NEXT: {{  $}}
+    ; GCN-NEXT: GLOBAL_LOAD_LDS_DWORD_SADDR killed $sgpr0_sgpr1, killed $vgpr0, 32, 2, implicit $m0, implicit $exec
+    ; GCN-NEXT: $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec, implicit $exec
+    ; GCN-NEXT: FLAT_STORE_DWORDX2 killed renamable $vgpr2_vgpr3, killed renamable $vgpr0_vgpr1, 0, 0, implicit $exec, implicit $flat_scr
+    GLOBAL_LOAD_LDS_DWORD_SADDR killed $sgpr0_sgpr1, killed $vgpr0, 32, 2, implicit $m0, implicit $exec
+    $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec, implicit $exec
+    FLAT_STORE_DWORDX2 killed renamable $vgpr2_vgpr3, killed renamable $vgpr0_vgpr1, 0, 0, implicit $exec, implicit $flat_scr
+...
diff --git a/llvm/test/CodeGen/AMDGPU/hazards-gfx950.mir b/llvm/test/CodeGen/AMDGPU/hazards-gfx950.mir
index d50442a7cd4bdf..49576433ab54da 100644
--- a/llvm/test/CodeGen/AMDGPU/hazards-gfx950.mir
+++ b/llvm/test/CodeGen/AMDGPU/hazards-gfx950.mir
@@ -1223,21 +1223,3 @@ body:             |
     early-clobber renamable $vgpr2 = V_CVT_SCALEF32_SR_PK_FP4_F16_e64 8, killed $vgpr0, 0, killed $vgpr3, 4, killed $vgpr1, killed $vgpr1, 0, implicit $mode, implicit $exec
     S_SETPC_B64_return undef $sgpr30_sgpr31, implicit killed $vgpr0
 ...
-
----
-name:            test_flat_valu_hazard
-noVRegs:         true
-body:             |
-  bb.0:
-    liveins: $vgpr0, $vgpr1
-
-    ; GCN-LABEL: name: test_flat_valu_hazard
-    ; GCN: liveins: $vgpr0, $vgpr1
-    ; GCN-NEXT: {{  $}}
-    ; GCN-NEXT: GLOBAL_LOAD_LDS_DWORD_SADDR killed $sgpr0_sgpr1, killed $vgpr0, 32, 2, implicit $m0, implicit $exec
-    ; GCN-NEXT: $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec, implicit $exec
-    ; GCN-NEXT: FLAT_STORE_DWORDX2 killed renamable $vgpr2_vgpr3, killed renamable $vgpr0_vgpr1, 0, 0, implicit $exec, implicit $flat_scr
-    GLOBAL_LOAD_LDS_DWORD_SADDR killed $sgpr0_sgpr1, killed $vgpr0, 32, 2, implicit $m0, implicit $exec
-    $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec, implicit $exec
-    FLAT_STORE_DWORDX2 killed renamable $vgpr2_vgpr3, killed renamable $vgpr0_vgpr1, 0, 0, implicit $exec, implicit $flat_scr
-...



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