[clang] [llvm] [AMDGPU] Improve selection of ballot.i64 intrinsic in wave32 mode. (PR #71556)

Valery Pykhtin via cfe-commits cfe-commits at lists.llvm.org
Mon Nov 20 23:41:25 PST 2023


https://github.com/vpykhtin updated https://github.com/llvm/llvm-project/pull/71556

>From f4ff530d27334a8ba8c986d321efd4ab751b6476 Mon Sep 17 00:00:00 2001
From: Valery Pykhtin <valery.pykhtin at gmail.com>
Date: Mon, 20 Nov 2023 15:22:16 +0100
Subject: [PATCH 1/2] run opt instcombine pass in the test

---
 .../AMDGPU/llvm.amdgcn.ballot.i64.wave32.ll   | 44 ++++++++++---------
 1 file changed, 23 insertions(+), 21 deletions(-)

diff --git a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ballot.i64.wave32.ll b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ballot.i64.wave32.ll
index 04a993eac82cd5e..bd319c6fc39ce62 100644
--- a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ballot.i64.wave32.ll
+++ b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ballot.i64.wave32.ll
@@ -1,8 +1,8 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc -march=amdgcn -global-isel=0 -mcpu=gfx1010 < %s | FileCheck %s --check-prefixes=CHECK,DAGISEL
-; RUN: llc -march=amdgcn -global-isel=0 -mcpu=gfx1100 -amdgpu-enable-delay-alu=0 < %s | FileCheck %s --check-prefixes=CHECK,DAGISEL
-; RUN: llc -march=amdgcn -global-isel -mcpu=gfx1010 < %s | FileCheck %s --check-prefixes=CHECK,GISEL
-; RUN: llc -march=amdgcn -global-isel -mcpu=gfx1100 -amdgpu-enable-delay-alu=0 < %s | FileCheck %s --check-prefixes=CHECK,GISEL
+; RUN: opt -mtriple=amdgcn-- -mcpu=gfx1010 -mattr=+wavefrontsize32,-wavefrontsize64 -passes=instcombine -o - < %s | llc -march=amdgcn -global-isel=0 -mcpu=gfx1010 - | FileCheck %s --check-prefixes=CHECK,DAGISEL
+; RUN: opt -mtriple=amdgcn-- -mcpu=gfx1100 -mattr=+wavefrontsize32,-wavefrontsize64 -passes=instcombine -o - < %s | llc -march=amdgcn -global-isel=0 -mcpu=gfx1100 -amdgpu-enable-delay-alu=0 - | FileCheck %s --check-prefixes=CHECK,DAGISEL
+; RUN: opt -mtriple=amdgcn-- -mcpu=gfx1010 -mattr=+wavefrontsize32,-wavefrontsize64 -passes=instcombine -o - < %s | llc -march=amdgcn -global-isel -mcpu=gfx1010 - | FileCheck %s --check-prefixes=CHECK,GISEL
+; RUN: opt -mtriple=amdgcn-- -mcpu=gfx1100 -mattr=+wavefrontsize32,-wavefrontsize64 -passes=instcombine -o - < %s | llc -march=amdgcn -global-isel -mcpu=gfx1100 -amdgpu-enable-delay-alu=0 - | FileCheck %s --check-prefixes=CHECK,GISEL
 
 declare i64 @llvm.amdgcn.ballot.i64(i1)
 declare i64 @llvm.ctpop.i64(i64)
@@ -40,12 +40,20 @@ define amdgpu_cs i64 @constant_true() {
 ; Test ballot of a non-comparison operation
 
 define amdgpu_cs i64 @non_compare(i32 %x) {
-; CHECK-LABEL: non_compare:
-; CHECK:       ; %bb.0:
-; CHECK-NEXT:    v_and_b32_e32 v0, 1, v0
-; CHECK-NEXT:    s_mov_b32 s1, 0
-; CHECK-NEXT:    v_cmp_ne_u32_e64 s0, 0, v0
-; CHECK-NEXT:    ; return to shader part epilog
+; DAGISEL-LABEL: non_compare:
+; DAGISEL:       ; %bb.0:
+; DAGISEL-NEXT:    v_and_b32_e32 v0, 1, v0
+; DAGISEL-NEXT:    s_mov_b32 s1, 0
+; DAGISEL-NEXT:    v_cmp_ne_u32_e64 s0, 0, v0
+; DAGISEL-NEXT:    ; return to shader part epilog
+;
+; GISEL-LABEL: non_compare:
+; GISEL:       ; %bb.0:
+; GISEL-NEXT:    v_and_b32_e32 v0, 1, v0
+; GISEL-NEXT:    s_mov_b32 s1, 0
+; GISEL-NEXT:    v_and_b32_e32 v0, 1, v0
+; GISEL-NEXT:    v_cmp_ne_u32_e64 s0, 0, v0
+; GISEL-NEXT:    ; return to shader part epilog
   %trunc = trunc i32 %x to i1
   %ballot = call i64 @llvm.amdgcn.ballot.i64(i1 %trunc)
   ret i64 %ballot
@@ -65,17 +73,11 @@ define amdgpu_cs i64 @compare_ints(i32 %x, i32 %y) {
 }
 
 define amdgpu_cs i64 @compare_int_with_constant(i32 %x) {
-; DAGISEL-LABEL: compare_int_with_constant:
-; DAGISEL:       ; %bb.0:
-; DAGISEL-NEXT:    v_cmp_lt_i32_e64 s0, 0x62, v0
-; DAGISEL-NEXT:    s_mov_b32 s1, 0
-; DAGISEL-NEXT:    ; return to shader part epilog
-;
-; GISEL-LABEL: compare_int_with_constant:
-; GISEL:       ; %bb.0:
-; GISEL-NEXT:    v_cmp_le_i32_e64 s0, 0x63, v0
-; GISEL-NEXT:    s_mov_b32 s1, 0
-; GISEL-NEXT:    ; return to shader part epilog
+; CHECK-LABEL: compare_int_with_constant:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    v_cmp_lt_i32_e64 s0, 0x62, v0
+; CHECK-NEXT:    s_mov_b32 s1, 0
+; CHECK-NEXT:    ; return to shader part epilog
   %cmp = icmp sge i32 %x, 99
   %ballot = call i64 @llvm.amdgcn.ballot.i64(i1 %cmp)
   ret i64 %ballot

>From e97e128f39639ab278a83f6aec99b0d7a8753bd7 Mon Sep 17 00:00:00 2001
From: Valery Pykhtin <valery.pykhtin at gmail.com>
Date: Mon, 20 Nov 2023 15:29:31 +0100
Subject: [PATCH 2/2] add instcombine rule

---
 .../CodeGenOpenCL/builtins-amdgcn-wave32.cl   |  8 +--
 llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp |  5 +-
 .../AMDGPU/AMDGPUInstCombineIntrinsic.cpp     | 12 ++++
 .../AMDGPU/llvm.amdgcn.ballot.i64.wave32.ll   | 68 +++++++++----------
 .../InstCombine/AMDGPU/amdgcn-intrinsics.ll   |  6 +-
 5 files changed, 54 insertions(+), 45 deletions(-)

diff --git a/clang/test/CodeGenOpenCL/builtins-amdgcn-wave32.cl b/clang/test/CodeGenOpenCL/builtins-amdgcn-wave32.cl
index 43553131f63c549..a0e27ce22fe7d9c 100644
--- a/clang/test/CodeGenOpenCL/builtins-amdgcn-wave32.cl
+++ b/clang/test/CodeGenOpenCL/builtins-amdgcn-wave32.cl
@@ -24,13 +24,11 @@ void test_ballot_wave32_target_attr(global uint* out, int a, int b)
 }
 
 // CHECK-LABEL: @test_read_exec(
-// CHECK: call i64 @llvm.amdgcn.ballot.i64(i1 true)
+// CHECK: call i32 @llvm.amdgcn.ballot.i32(i1 true)
 void test_read_exec(global uint* out) {
   *out = __builtin_amdgcn_read_exec();
 }
 
-// CHECK: declare i64 @llvm.amdgcn.ballot.i64(i1) #[[$NOUNWIND_READONLY:[0-9]+]]
-
 // CHECK-LABEL: @test_read_exec_lo(
 // CHECK: call i32 @llvm.amdgcn.ballot.i32(i1 true)
 void test_read_exec_lo(global uint* out) {
@@ -38,9 +36,7 @@ void test_read_exec_lo(global uint* out) {
 }
 
 // CHECK-LABEL: @test_read_exec_hi(
-// CHECK: call i64 @llvm.amdgcn.ballot.i64(i1 true)
-// CHECK: lshr i64 [[A:%.*]], 32
-// CHECK: trunc i64 [[B:%.*]] to i32
+// CHECK: store i32 0, ptr addrspace(1) %out
 void test_read_exec_hi(global uint* out) {
   *out = __builtin_amdgcn_read_exec_hi();
 }
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp b/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
index ead3f51d6acdc5a..a0ff1bd579b14b2 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
@@ -2314,9 +2314,8 @@ void AMDGPUDAGToDAGISel::SelectBRCOND(SDNode *N) {
     SDValue VCMP = Cond->getOperand(0);
     auto CC = cast<CondCodeSDNode>(Cond->getOperand(2))->get();
     auto *CRHS = dyn_cast<ConstantSDNode>(Cond->getOperand(1));
-    if ((CC == ISD::SETEQ || CC == ISD::SETNE) && CRHS && CRHS->isZero() &&
-        // TODO: make condition below an assert after fixing ballot bitwidth.
-        VCMP.getValueType().getSizeInBits() == ST->getWavefrontSize()) {
+    if ((CC == ISD::SETEQ || CC == ISD::SETNE) && CRHS && CRHS->isZero()) {
+      assert(VCMP.getValueType().getSizeInBits() == ST->getWavefrontSize());
       // %VCMP = i(WaveSize) AMDGPUISD::SETCC ...
       // %C = i1 ISD::SETCC %VCMP, 0, setne/seteq
       // BRCOND i1 %C, %BB
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp b/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
index 5296415ab4c36da..510f0a59719ecdb 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
@@ -961,6 +961,18 @@ GCNTTIImpl::instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const {
         return IC.replaceInstUsesWith(II, Constant::getNullValue(II.getType()));
       }
     }
+    if (ST->isWave32() && II.getType()->getIntegerBitWidth() == 64) {
+      // %b64 = call i64 ballot.i64(...)
+      // =>
+      // %b32 = call i32 ballot.i32(...)
+      // %b64 = zext i32 %b32 to i64
+      Function *NewF = Intrinsic::getDeclaration(
+          II.getModule(), Intrinsic::amdgcn_ballot, {IC.Builder.getInt32Ty()});
+      CallInst *NewCall = IC.Builder.CreateCall(NewF, {II.getArgOperand(0)});
+      Value *CastedCall = IC.Builder.CreateZExtOrBitCast(NewCall, II.getType());
+      CastedCall->takeName(&II);
+      return IC.replaceInstUsesWith(II, CastedCall);
+    }
     break;
   }
   case Intrinsic::amdgcn_wqm_vote: {
diff --git a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ballot.i64.wave32.ll b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ballot.i64.wave32.ll
index bd319c6fc39ce62..8647718d7a77b98 100644
--- a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ballot.i64.wave32.ll
+++ b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ballot.i64.wave32.ll
@@ -22,17 +22,11 @@ define amdgpu_cs i64 @constant_false() {
 ; Test ballot(1)
 
 define amdgpu_cs i64 @constant_true() {
-; DAGISEL-LABEL: constant_true:
-; DAGISEL:       ; %bb.0:
-; DAGISEL-NEXT:    s_mov_b32 s0, exec_lo
-; DAGISEL-NEXT:    s_mov_b32 s1, exec_hi
-; DAGISEL-NEXT:    ; return to shader part epilog
-;
-; GISEL-LABEL: constant_true:
-; GISEL:       ; %bb.0:
-; GISEL-NEXT:    s_mov_b32 s0, exec_lo
-; GISEL-NEXT:    s_mov_b32 s1, 0
-; GISEL-NEXT:    ; return to shader part epilog
+; CHECK-LABEL: constant_true:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    s_mov_b32 s0, exec_lo
+; CHECK-NEXT:    s_mov_b32 s1, 0
+; CHECK-NEXT:    ; return to shader part epilog
   %ballot = call i64 @llvm.amdgcn.ballot.i64(i1 1)
   ret i64 %ballot
 }
@@ -97,9 +91,9 @@ define amdgpu_cs i64 @compare_floats(float %x, float %y) {
 define amdgpu_cs i64 @ctpop_of_ballot(float %x, float %y) {
 ; CHECK-LABEL: ctpop_of_ballot:
 ; CHECK:       ; %bb.0:
-; CHECK-NEXT:    v_cmp_gt_f32_e64 s0, v0, v1
+; CHECK-NEXT:    v_cmp_gt_f32_e32 vcc_lo, v0, v1
 ; CHECK-NEXT:    s_mov_b32 s1, 0
-; CHECK-NEXT:    s_bcnt1_i32_b64 s0, s[0:1]
+; CHECK-NEXT:    s_bcnt1_i32_b32 s0, vcc_lo
 ; CHECK-NEXT:    ; return to shader part epilog
   %cmp = fcmp ogt float %x, %y
   %ballot = call i64 @llvm.amdgcn.ballot.i64(i1 %cmp)
@@ -108,19 +102,30 @@ define amdgpu_cs i64 @ctpop_of_ballot(float %x, float %y) {
 }
 
 define amdgpu_cs i32 @branch_divergent_ballot64_ne_zero_compare(i32 %v) {
-; CHECK-LABEL: branch_divergent_ballot64_ne_zero_compare:
-; CHECK:       ; %bb.0:
-; CHECK-NEXT:    v_cmp_gt_u32_e64 s0, 12, v0
-; CHECK-NEXT:    s_mov_b32 s1, 0
-; CHECK-NEXT:    s_cmp_eq_u64 s[0:1], 0
-; CHECK-NEXT:    s_cbranch_scc1 .LBB7_2
-; CHECK-NEXT:  ; %bb.1: ; %true
-; CHECK-NEXT:    s_mov_b32 s0, 42
-; CHECK-NEXT:    s_branch .LBB7_3
-; CHECK-NEXT:  .LBB7_2: ; %false
-; CHECK-NEXT:    s_mov_b32 s0, 33
-; CHECK-NEXT:    s_branch .LBB7_3
-; CHECK-NEXT:  .LBB7_3:
+; DAGISEL-LABEL: branch_divergent_ballot64_ne_zero_compare:
+; DAGISEL:       ; %bb.0:
+; DAGISEL-NEXT:    v_cmp_gt_u32_e32 vcc_lo, 12, v0
+; DAGISEL-NEXT:    s_cbranch_vccz .LBB7_2
+; DAGISEL-NEXT:  ; %bb.1: ; %true
+; DAGISEL-NEXT:    s_mov_b32 s0, 42
+; DAGISEL-NEXT:    s_branch .LBB7_3
+; DAGISEL-NEXT:  .LBB7_2: ; %false
+; DAGISEL-NEXT:    s_mov_b32 s0, 33
+; DAGISEL-NEXT:    s_branch .LBB7_3
+; DAGISEL-NEXT:  .LBB7_3:
+;
+; GISEL-LABEL: branch_divergent_ballot64_ne_zero_compare:
+; GISEL:       ; %bb.0:
+; GISEL-NEXT:    v_cmp_gt_u32_e32 vcc_lo, 12, v0
+; GISEL-NEXT:    s_cmp_eq_u32 vcc_lo, 0
+; GISEL-NEXT:    s_cbranch_scc1 .LBB7_2
+; GISEL-NEXT:  ; %bb.1: ; %true
+; GISEL-NEXT:    s_mov_b32 s0, 42
+; GISEL-NEXT:    s_branch .LBB7_3
+; GISEL-NEXT:  .LBB7_2: ; %false
+; GISEL-NEXT:    s_mov_b32 s0, 33
+; GISEL-NEXT:    s_branch .LBB7_3
+; GISEL-NEXT:  .LBB7_3:
   %c = icmp ult i32 %v, 12
   %ballot = call i64 @llvm.amdgcn.ballot.i64(i1 %c)
   %ballot_ne_zero = icmp ne i64 %ballot, 0
@@ -136,12 +141,8 @@ define amdgpu_cs i32 @branch_divergent_ballot64_ne_zero_and(i32 %v1, i32 %v2) {
 ; DAGISEL:       ; %bb.0:
 ; DAGISEL-NEXT:    v_cmp_gt_u32_e32 vcc_lo, 12, v0
 ; DAGISEL-NEXT:    v_cmp_lt_u32_e64 s0, 34, v1
-; DAGISEL-NEXT:    s_mov_b32 s1, 0
-; DAGISEL-NEXT:    s_and_b32 s0, vcc_lo, s0
-; DAGISEL-NEXT:    v_cndmask_b32_e64 v0, 0, 1, s0
-; DAGISEL-NEXT:    v_cmp_ne_u32_e64 s0, 0, v0
-; DAGISEL-NEXT:    s_cmp_eq_u64 s[0:1], 0
-; DAGISEL-NEXT:    s_cbranch_scc1 .LBB8_2
+; DAGISEL-NEXT:    s_and_b32 vcc_lo, vcc_lo, s0
+; DAGISEL-NEXT:    s_cbranch_vccz .LBB8_2
 ; DAGISEL-NEXT:  ; %bb.1: ; %true
 ; DAGISEL-NEXT:    s_mov_b32 s0, 42
 ; DAGISEL-NEXT:    s_branch .LBB8_3
@@ -154,9 +155,8 @@ define amdgpu_cs i32 @branch_divergent_ballot64_ne_zero_and(i32 %v1, i32 %v2) {
 ; GISEL:       ; %bb.0:
 ; GISEL-NEXT:    v_cmp_gt_u32_e32 vcc_lo, 12, v0
 ; GISEL-NEXT:    v_cmp_lt_u32_e64 s0, 34, v1
-; GISEL-NEXT:    s_mov_b32 s1, 0
 ; GISEL-NEXT:    s_and_b32 s0, vcc_lo, s0
-; GISEL-NEXT:    s_cmp_eq_u64 s[0:1], 0
+; GISEL-NEXT:    s_cmp_eq_u32 s0, 0
 ; GISEL-NEXT:    s_cbranch_scc1 .LBB8_2
 ; GISEL-NEXT:  ; %bb.1: ; %true
 ; GISEL-NEXT:    s_mov_b32 s0, 42
diff --git a/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll b/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll
index 804283cc20cd6a3..94c32e3cbe99f72 100644
--- a/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll
+++ b/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll
@@ -2599,7 +2599,8 @@ declare i32 @llvm.amdgcn.ballot.i32(i1) nounwind readnone convergent
 
 define i64 @ballot_nocombine_64(i1 %i) {
 ; CHECK-LABEL: @ballot_nocombine_64(
-; CHECK-NEXT:    [[B:%.*]] = call i64 @llvm.amdgcn.ballot.i64(i1 [[I:%.*]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.amdgcn.ballot.i32(i1 [[I:%.*]])
+; CHECK-NEXT:    [[B:%.*]] = zext i32 [[TMP1]] to i64
 ; CHECK-NEXT:    ret i64 [[B]]
 ;
   %b = call i64 @llvm.amdgcn.ballot.i64(i1 %i)
@@ -2616,7 +2617,8 @@ define i64 @ballot_zero_64() {
 
 define i64 @ballot_one_64() {
 ; CHECK-LABEL: @ballot_one_64(
-; CHECK-NEXT:    [[B:%.*]] = call i64 @llvm.amdgcn.ballot.i64(i1 true)
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.amdgcn.ballot.i32(i1 true)
+; CHECK-NEXT:    [[B:%.*]] = zext i32 [[TMP1]] to i64
 ; CHECK-NEXT:    ret i64 [[B]]
 ;
   %b = call i64 @llvm.amdgcn.ballot.i64(i1 1)



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