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[AMDGPU] SIInsertHardClause: add configurable clause length limit #142343

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Merged
merged 2 commits into from
Jun 4, 2025

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perlfu
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@perlfu perlfu commented Jun 2, 2025

Add command line and function attribute configuration of hard clause length limit (within hardware maximum).
This allows performance tuning for shaders which benefit from smaller clauses.

Add command line and function attribute configuration of hard
clause length limit (within hardware maximum).
@llvmbot
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llvmbot commented Jun 2, 2025

@llvm/pr-subscribers-backend-amdgpu

Author: Carl Ritson (perlfu)

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Add command line and function attribute configuration of hard clause length limit (within hardware maximum).


Patch is 53.44 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/142343.diff

3 Files Affected:

  • (modified) llvm/lib/Target/AMDGPU/SIInsertHardClauses.cpp (+15-2)
  • (added) llvm/test/CodeGen/AMDGPU/hard-clause-limit-attr.mir (+178)
  • (added) llvm/test/CodeGen/AMDGPU/hard-clause-limit.mir (+233)
diff --git a/llvm/lib/Target/AMDGPU/SIInsertHardClauses.cpp b/llvm/lib/Target/AMDGPU/SIInsertHardClauses.cpp
index eb0977b92d5ab..0741ae0bda55e 100644
--- a/llvm/lib/Target/AMDGPU/SIInsertHardClauses.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInsertHardClauses.cpp
@@ -42,6 +42,12 @@ using namespace llvm;
 
 #define DEBUG_TYPE "si-insert-hard-clauses"
 
+static cl::opt<unsigned>
+    HardClauseLengthLimit("amdgpu-hard-clause-length-limit",
+                          cl::desc("Maximum number of memory instructions to "
+                                   "place in the same hard clause"),
+                          cl::init(255), cl::Hidden);
+
 namespace {
 
 enum HardClauseType {
@@ -185,11 +191,18 @@ class SIInsertHardClauses {
   }
 
   bool run(MachineFunction &MF) {
-
     ST = &MF.getSubtarget<GCNSubtarget>();
     if (!ST->hasHardClauses())
       return false;
 
+    unsigned MaxClauseLength = MF.getFunction().getFnAttributeAsParsedInteger(
+        "amdgpu-hard-clause-length-limit", HardClauseLengthLimit);
+    if (HardClauseLengthLimit.getNumOccurrences())
+      MaxClauseLength = HardClauseLengthLimit;
+    MaxClauseLength = std::min(MaxClauseLength, ST->maxHardClauseLength());
+    if (!MaxClauseLength)
+      return false;
+
     const SIInstrInfo *SII = ST->getInstrInfo();
     const TargetRegisterInfo *TRI = ST->getRegisterInfo();
 
@@ -212,7 +225,7 @@ class SIInsertHardClauses {
           }
         }
 
-        if (CI.Length == ST->maxHardClauseLength() ||
+        if (CI.Length == MaxClauseLength ||
             (CI.Length && Type != HARDCLAUSE_INTERNAL &&
              Type != HARDCLAUSE_IGNORE &&
              (Type != CI.Type ||
diff --git a/llvm/test/CodeGen/AMDGPU/hard-clause-limit-attr.mir b/llvm/test/CodeGen/AMDGPU/hard-clause-limit-attr.mir
new file mode 100644
index 0000000000000..cfd4ea155316a
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/hard-clause-limit-attr.mir
@@ -0,0 +1,178 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -mtriple=amdgcn -mcpu=gfx1100 -verify-machineinstrs -run-pass si-insert-hard-clauses %s -o - | FileCheck %s -check-prefix=GFX11
+
+--- |
+  define void @long_clause_32() "amdgpu-hard-clause-length-limit"="32" {
+    ret void
+  }
+  define void @long_clause_7() "amdgpu-hard-clause-length-limit"="7" {
+    ret void
+  }
+
+---
+name: long_clause_32
+tracksRegLiveness: true
+body: |
+  bb.0:
+    liveins: $sgpr0_sgpr1_sgpr2_sgpr3, $vgpr0
+    ; GFX11-LABEL: name: long_clause_32
+    ; GFX11: liveins: $sgpr0_sgpr1_sgpr2_sgpr3, $vgpr0
+    ; GFX11-NEXT: {{  $}}
+    ; GFX11-NEXT: BUNDLE implicit-def $vgpr1, implicit-def $vgpr1_lo16, implicit-def $vgpr1_hi16, implicit-def $vgpr2, implicit-def $vgpr2_lo16, implicit-def $vgpr2_hi16, implicit-def $vgpr3, implicit-def $vgpr3_lo16, implicit-def $vgpr3_hi16, implicit-def $vgpr4, implicit-def $vgpr4_lo16, implicit-def $vgpr4_hi16, implicit-def $vgpr5, implicit-def $vgpr5_lo16, implicit-def $vgpr5_hi16, implicit-def $vgpr6, implicit-def $vgpr6_lo16, implicit-def $vgpr6_hi16, implicit-def $vgpr7, implicit-def $vgpr7_lo16, implicit-def $vgpr7_hi16, implicit-def $vgpr8, implicit-def $vgpr8_lo16, implicit-def $vgpr8_hi16, implicit-def $vgpr9, implicit-def $vgpr9_lo16, implicit-def $vgpr9_hi16, implicit-def $vgpr10, implicit-def $vgpr10_lo16, implicit-def $vgpr10_hi16, implicit-def $vgpr11, implicit-def $vgpr11_lo16, implicit-def $vgpr11_hi16, implicit-def $vgpr12, implicit-def $vgpr12_lo16, implicit-def $vgpr12_hi16, implicit-def $vgpr13, implicit-def $vgpr13_lo16, implicit-def $vgpr13_hi16, implicit-def $vgpr14, implicit-def $vgpr14_lo16, implicit-def $vgpr14_hi16, implicit-def $vgpr15, implicit-def $vgpr15_lo16, implicit-def $vgpr15_hi16, implicit-def $vgpr16, implicit-def $vgpr16_lo16, implicit-def $vgpr16_hi16, implicit-def $vgpr17, implicit-def $vgpr17_lo16, implicit-def $vgpr17_hi16, implicit-def $vgpr18, implicit-def $vgpr18_lo16, implicit-def $vgpr18_hi16, implicit-def $vgpr19, implicit-def $vgpr19_lo16, implicit-def $vgpr19_hi16, implicit-def $vgpr20, implicit-def $vgpr20_lo16, implicit-def $vgpr20_hi16, implicit-def $vgpr21, implicit-def $vgpr21_lo16, implicit-def $vgpr21_hi16, implicit-def $vgpr22, implicit-def $vgpr22_lo16, implicit-def $vgpr22_hi16, implicit-def $vgpr23, implicit-def $vgpr23_lo16, implicit-def $vgpr23_hi16, implicit-def $vgpr24, implicit-def $vgpr24_lo16, implicit-def $vgpr24_hi16, implicit-def $vgpr25, implicit-def $vgpr25_lo16, implicit-def $vgpr25_hi16, implicit-def $vgpr26, implicit-def $vgpr26_lo16, implicit-def $vgpr26_hi16, implicit-def $vgpr27, implicit-def $vgpr27_lo16, implicit-def $vgpr27_hi16, implicit-def $vgpr28, implicit-def $vgpr28_lo16, implicit-def $vgpr28_hi16, implicit-def $vgpr29, implicit-def $vgpr29_lo16, implicit-def $vgpr29_hi16, implicit-def $vgpr30, implicit-def $vgpr30_lo16, implicit-def $vgpr30_hi16, implicit-def $vgpr31, implicit-def $vgpr31_lo16, implicit-def $vgpr31_hi16, implicit-def $vgpr32, implicit-def $vgpr32_lo16, implicit-def $vgpr32_hi16, implicit $vgpr0, implicit $sgpr0_sgpr1_sgpr2_sgpr3, implicit $exec {
+    ; GFX11-NEXT:   S_CLAUSE 31
+    ; GFX11-NEXT:   $vgpr1 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 4, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr2 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 8, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr3 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 12, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr4 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 16, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr5 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 20, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr6 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 24, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr7 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 28, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr8 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 32, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr9 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 36, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr10 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 40, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr11 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 44, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr12 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 48, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr13 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 52, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr14 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 56, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr15 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 60, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr16 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 64, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr17 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 68, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr18 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 72, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr19 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 76, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr20 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 80, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr21 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 84, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr22 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 88, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr23 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 92, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr24 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 96, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr25 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 100, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr26 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 104, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr27 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 108, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr28 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 112, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr29 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 116, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr30 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 120, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr31 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 124, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr32 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 128, 0, 0, implicit $exec
+    ; GFX11-NEXT: }
+    $vgpr1 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 4, 0, 0, implicit $exec
+    $vgpr2 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 8, 0, 0, implicit $exec
+    $vgpr3 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 12, 0, 0, implicit $exec
+    $vgpr4 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 16, 0, 0, implicit $exec
+    $vgpr5 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 20, 0, 0, implicit $exec
+    $vgpr6 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 24, 0, 0, implicit $exec
+    $vgpr7 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 28, 0, 0, implicit $exec
+    $vgpr8 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 32, 0, 0, implicit $exec
+    $vgpr9 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 36, 0, 0, implicit $exec
+    $vgpr10 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 40, 0, 0, implicit $exec
+    $vgpr11 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 44, 0, 0, implicit $exec
+    $vgpr12 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 48, 0, 0, implicit $exec
+    $vgpr13 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 52, 0, 0, implicit $exec
+    $vgpr14 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 56, 0, 0, implicit $exec
+    $vgpr15 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 60, 0, 0, implicit $exec
+    $vgpr16 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 64, 0, 0, implicit $exec
+    $vgpr17 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 68, 0, 0, implicit $exec
+    $vgpr18 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 72, 0, 0, implicit $exec
+    $vgpr19 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 76, 0, 0, implicit $exec
+    $vgpr20 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 80, 0, 0, implicit $exec
+    $vgpr21 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 84, 0, 0, implicit $exec
+    $vgpr22 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 88, 0, 0, implicit $exec
+    $vgpr23 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 92, 0, 0, implicit $exec
+    $vgpr24 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 96, 0, 0, implicit $exec
+    $vgpr25 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 100, 0, 0, implicit $exec
+    $vgpr26 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 104, 0, 0, implicit $exec
+    $vgpr27 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 108, 0, 0, implicit $exec
+    $vgpr28 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 112, 0, 0, implicit $exec
+    $vgpr29 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 116, 0, 0, implicit $exec
+    $vgpr30 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 120, 0, 0, implicit $exec
+    $vgpr31 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 124, 0, 0, implicit $exec
+    $vgpr32 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 128, 0, 0, implicit $exec
+...
+
+---
+name: long_clause_7
+tracksRegLiveness: true
+body: |
+  bb.0:
+    liveins: $sgpr0_sgpr1_sgpr2_sgpr3, $vgpr0
+    ; GFX11-LABEL: name: long_clause_7
+    ; GFX11: liveins: $sgpr0_sgpr1_sgpr2_sgpr3, $vgpr0
+    ; GFX11-NEXT: {{  $}}
+    ; GFX11-NEXT: BUNDLE implicit-def $vgpr1, implicit-def $vgpr1_lo16, implicit-def $vgpr1_hi16, implicit-def $vgpr2, implicit-def $vgpr2_lo16, implicit-def $vgpr2_hi16, implicit-def $vgpr3, implicit-def $vgpr3_lo16, implicit-def $vgpr3_hi16, implicit-def $vgpr4, implicit-def $vgpr4_lo16, implicit-def $vgpr4_hi16, implicit-def $vgpr5, implicit-def $vgpr5_lo16, implicit-def $vgpr5_hi16, implicit-def $vgpr6, implicit-def $vgpr6_lo16, implicit-def $vgpr6_hi16, implicit-def $vgpr7, implicit-def $vgpr7_lo16, implicit-def $vgpr7_hi16, implicit $vgpr0, implicit $sgpr0_sgpr1_sgpr2_sgpr3, implicit $exec {
+    ; GFX11-NEXT:   S_CLAUSE 6
+    ; GFX11-NEXT:   $vgpr1 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 4, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr2 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 8, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr3 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 12, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr4 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 16, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr5 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 20, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr6 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 24, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr7 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 28, 0, 0, implicit $exec
+    ; GFX11-NEXT: }
+    ; GFX11-NEXT: BUNDLE implicit-def $vgpr8, implicit-def $vgpr8_lo16, implicit-def $vgpr8_hi16, implicit-def $vgpr9, implicit-def $vgpr9_lo16, implicit-def $vgpr9_hi16, implicit-def $vgpr10, implicit-def $vgpr10_lo16, implicit-def $vgpr10_hi16, implicit-def $vgpr11, implicit-def $vgpr11_lo16, implicit-def $vgpr11_hi16, implicit-def $vgpr12, implicit-def $vgpr12_lo16, implicit-def $vgpr12_hi16, implicit-def $vgpr13, implicit-def $vgpr13_lo16, implicit-def $vgpr13_hi16, implicit-def $vgpr14, implicit-def $vgpr14_lo16, implicit-def $vgpr14_hi16, implicit $vgpr0, implicit $sgpr0_sgpr1_sgpr2_sgpr3, implicit $exec {
+    ; GFX11-NEXT:   S_CLAUSE 6
+    ; GFX11-NEXT:   $vgpr8 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 32, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr9 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 36, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr10 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 40, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr11 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 44, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr12 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 48, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr13 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 52, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr14 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 56, 0, 0, implicit $exec
+    ; GFX11-NEXT: }
+    ; GFX11-NEXT: BUNDLE implicit-def $vgpr15, implicit-def $vgpr15_lo16, implicit-def $vgpr15_hi16, implicit-def $vgpr16, implicit-def $vgpr16_lo16, implicit-def $vgpr16_hi16, implicit-def $vgpr17, implicit-def $vgpr17_lo16, implicit-def $vgpr17_hi16, implicit-def $vgpr18, implicit-def $vgpr18_lo16, implicit-def $vgpr18_hi16, implicit-def $vgpr19, implicit-def $vgpr19_lo16, implicit-def $vgpr19_hi16, implicit-def $vgpr20, implicit-def $vgpr20_lo16, implicit-def $vgpr20_hi16, implicit-def $vgpr21, implicit-def $vgpr21_lo16, implicit-def $vgpr21_hi16, implicit $vgpr0, implicit $sgpr0_sgpr1_sgpr2_sgpr3, implicit $exec {
+    ; GFX11-NEXT:   S_CLAUSE 6
+    ; GFX11-NEXT:   $vgpr15 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 60, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr16 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 64, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr17 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 68, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr18 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 72, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr19 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 76, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr20 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 80, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr21 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 84, 0, 0, implicit $exec
+    ; GFX11-NEXT: }
+    ; GFX11-NEXT: BUNDLE implicit-def $vgpr22, implicit-def $vgpr22_lo16, implicit-def $vgpr22_hi16, implicit-def $vgpr23, implicit-def $vgpr23_lo16, implicit-def $vgpr23_hi16, implicit-def $vgpr24, implicit-def $vgpr24_lo16, implicit-def $vgpr24_hi16, implicit-def $vgpr25, implicit-def $vgpr25_lo16, implicit-def $vgpr25_hi16, implicit-def $vgpr26, implicit-def $vgpr26_lo16, implicit-def $vgpr26_hi16, implicit-def $vgpr27, implicit-def $vgpr27_lo16, implicit-def $vgpr27_hi16, implicit-def $vgpr28, implicit-def $vgpr28_lo16, implicit-def $vgpr28_hi16, implicit $vgpr0, implicit $sgpr0_sgpr1_sgpr2_sgpr3, implicit $exec {
+    ; GFX11-NEXT:   S_CLAUSE 6
+    ; GFX11-NEXT:   $vgpr22 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 88, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr23 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 92, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr24 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 96, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr25 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 100, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr26 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 104, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr27 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 108, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr28 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 112, 0, 0, implicit $exec
+    ; GFX11-NEXT: }
+    ; GFX11-NEXT: BUNDLE implicit-def $vgpr29, implicit-def $vgpr29_lo16, implicit-def $vgpr29_hi16, implicit-def $vgpr30, implicit-def $vgpr30_lo16, implicit-def $vgpr30_hi16, implicit-def $vgpr31, implicit-def $vgpr31_lo16, implicit-def $vgpr31_hi16, implicit-def $vgpr32, implicit-def $vgpr32_lo16, implicit-def $vgpr32_hi16, implicit $vgpr0, implicit $sgpr0_sgpr1_sgpr2_sgpr3, implicit $exec {
+    ; GFX11-NEXT:   S_CLAUSE 3
+    ; GFX11-NEXT:   $vgpr29 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 116, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr30 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 120, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr31 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 124, 0, 0, implicit $exec
+    ; GFX11-NEXT:   $vgpr32 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 128, 0, 0, implicit $exec
+    ; GFX11-NEXT: }
+    $vgpr1 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 4, 0, 0, implicit $exec
+    $vgpr2 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 8, 0, 0, implicit $exec
+    $vgpr3 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 12, 0, 0, implicit $exec
+    $vgpr4 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 16, 0, 0, implicit $exec
+    $vgpr5 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 20, 0, 0, implicit $exec
+    $vgpr6 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 24, 0, 0, implicit $exec
+    $vgpr7 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 28, 0, 0, implicit $exec
+    $vgpr8 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 32, 0, 0, implicit $exec
+    $vgpr9 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 36, 0, 0, implicit $exec
+    $vgpr10 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 40, 0, 0, implicit $exec
+    $vgpr11 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 44, 0, 0, implicit $exec
+    $vgpr12 = BUFFER_LOAD_DWORD_OFFEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, 0, 48, 0, 0, implicit $exec
+    $vgpr13...
[truncated]

@jayfoad
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jayfoad commented Jun 2, 2025

Add command line and function attribute configuration of hard clause length limit (within hardware maximum).

Why?

@perlfu
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perlfu commented Jun 2, 2025

Why?

In certain applications I am seeing large clauses to have a negative impact on performance.
For these cases using small clauses (e.g. 4 operations) boosts performance 1-2%.
(Disabling clausing entirely does not yield this benefit.)
I assume these cases have improved cache efficiency from interleaving lock-stepped waves rather than issuing long sequences of uninterrupted memory requests from each wave in turn.

I am gather data to see if a lower (than hardware maximum) limit might be beneficial overall.

@jayfoad
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jayfoad commented Jun 2, 2025

Why?

In certain applications I am seeing large clauses to have a negative impact on performance. For these cases using small clauses (e.g. 4 operations) boosts performance 1-2%. (Disabling clausing entirely does not yield this benefit.) I assume these cases have improved cache efficiency from interleaving lock-stepped waves rather than issuing long sequences of uninterrupted memory requests from each wave in turn.

I am gather data to see if a lower (than hardware maximum) limit might be beneficial overall.

Fair enough. Should mention in the commit description that it's for performance tuning.

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Seems reasonable

@perlfu perlfu merged commit e47e4d8 into llvm:main Jun 4, 2025
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3 participants