[llvm] [AArch64] Don't allow mixed partial reductions without i8mm (PR #137602)

Sam Tebbs via llvm-commits llvm-commits at lists.llvm.org
Mon Apr 28 02:10:07 PDT 2025


https://github.com/SamTebbs33 created https://github.com/llvm/llvm-project/pull/137602

Partial reductions with mixed extends should only be allowed if i8mm is present.

>From 01ea7d6439baaea6908f1b9007661cd97bb7c488 Mon Sep 17 00:00:00 2001
From: Samuel Tebbs <samuel.tebbs at arm.com>
Date: Wed, 23 Apr 2025 16:50:19 +0100
Subject: [PATCH] [AArch64] Don't allow mixed partial reductions without i8mm

---
 .../AArch64/AArch64TargetTransformInfo.cpp    |   5 +-
 .../partial-reduce-dot-product-mixed.ll       | 114 +++++++++++-------
 2 files changed, 72 insertions(+), 47 deletions(-)

diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
index c670b2ae71bf3..4c6803ed310b2 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -5345,10 +5345,9 @@ InstructionCost AArch64TTIImpl::getPartialReductionCost(
     return Invalid;
 
   // AArch64 supports lowering mixed extensions to a usdot but only if the
-  // i8mm or sve/streaming features are available.
+  // i8mm feature is available.
   if (OpAExtend == TTI::PR_None || OpBExtend == TTI::PR_None ||
-      (OpAExtend != OpBExtend && !ST->hasMatMulInt8() &&
-       !ST->isSVEorStreamingSVEAvailable()))
+      (OpAExtend != OpBExtend && !ST->hasMatMulInt8()))
     return Invalid;
 
   if (!BinOp || *BinOp != Instruction::Mul)
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/partial-reduce-dot-product-mixed.ll b/llvm/test/Transforms/LoopVectorize/AArch64/partial-reduce-dot-product-mixed.ll
index cdd23b8f4d761..5950a3f84502b 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/partial-reduce-dot-product-mixed.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/partial-reduce-dot-product-mixed.ll
@@ -46,38 +46,51 @@ define i32 @dotp_z_s(ptr %a, ptr %b) #0 {
 ; CHECK-NOI8MM-LABEL: define i32 @dotp_z_s(
 ; CHECK-NOI8MM-SAME: ptr [[A:%.*]], ptr [[B:%.*]]) #[[ATTR0:[0-9]+]] {
 ; CHECK-NOI8MM-NEXT:  entry:
+; CHECK-NOI8MM-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NOI8MM-NEXT:    [[TMP13:%.*]] = mul i64 [[TMP0]], 8
 ; CHECK-NOI8MM-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
 ; CHECK-NOI8MM:       vector.ph:
+; CHECK-NOI8MM-NEXT:    [[TMP14:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NOI8MM-NEXT:    [[TMP3:%.*]] = mul i64 [[TMP14]], 8
+; CHECK-NOI8MM-NEXT:    [[N_MOD_VF:%.*]] = urem i64 1024, [[TMP3]]
+; CHECK-NOI8MM-NEXT:    [[N_VEC:%.*]] = sub i64 1024, [[N_MOD_VF]]
+; CHECK-NOI8MM-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NOI8MM-NEXT:    [[TMP5:%.*]] = mul i64 [[TMP4]], 8
 ; CHECK-NOI8MM-NEXT:    br label [[VECTOR_BODY:%.*]]
 ; CHECK-NOI8MM:       vector.body:
 ; CHECK-NOI8MM-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
-; CHECK-NOI8MM-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[PARTIAL_REDUCE:%.*]], [[VECTOR_BODY]] ]
-; CHECK-NOI8MM-NEXT:    [[VEC_PHI1:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[PARTIAL_REDUCE5:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NOI8MM-NEXT:    [[VEC_PHI:%.*]] = phi <vscale x 4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP22:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NOI8MM-NEXT:    [[VEC_PHI1:%.*]] = phi <vscale x 4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP23:%.*]], [[VECTOR_BODY]] ]
 ; CHECK-NOI8MM-NEXT:    [[TMP1:%.*]] = getelementptr i8, ptr [[A]], i64 [[INDEX]]
 ; CHECK-NOI8MM-NEXT:    [[TMP2:%.*]] = getelementptr i8, ptr [[TMP1]], i32 0
-; CHECK-NOI8MM-NEXT:    [[TMP3:%.*]] = getelementptr i8, ptr [[TMP1]], i32 16
-; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD:%.*]] = load <16 x i8>, ptr [[TMP2]], align 1
-; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD2:%.*]] = load <16 x i8>, ptr [[TMP3]], align 1
-; CHECK-NOI8MM-NEXT:    [[TMP4:%.*]] = zext <16 x i8> [[WIDE_LOAD]] to <16 x i32>
-; CHECK-NOI8MM-NEXT:    [[TMP5:%.*]] = zext <16 x i8> [[WIDE_LOAD2]] to <16 x i32>
+; CHECK-NOI8MM-NEXT:    [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NOI8MM-NEXT:    [[TMP9:%.*]] = mul i64 [[TMP8]], 4
+; CHECK-NOI8MM-NEXT:    [[TMP10:%.*]] = getelementptr i8, ptr [[TMP1]], i64 [[TMP9]]
+; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD:%.*]] = load <vscale x 4 x i8>, ptr [[TMP2]], align 1
+; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD2:%.*]] = load <vscale x 4 x i8>, ptr [[TMP10]], align 1
+; CHECK-NOI8MM-NEXT:    [[TMP11:%.*]] = zext <vscale x 4 x i8> [[WIDE_LOAD]] to <vscale x 4 x i32>
+; CHECK-NOI8MM-NEXT:    [[TMP12:%.*]] = zext <vscale x 4 x i8> [[WIDE_LOAD2]] to <vscale x 4 x i32>
 ; CHECK-NOI8MM-NEXT:    [[TMP6:%.*]] = getelementptr i8, ptr [[B]], i64 [[INDEX]]
 ; CHECK-NOI8MM-NEXT:    [[TMP7:%.*]] = getelementptr i8, ptr [[TMP6]], i32 0
-; CHECK-NOI8MM-NEXT:    [[TMP8:%.*]] = getelementptr i8, ptr [[TMP6]], i32 16
-; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD3:%.*]] = load <16 x i8>, ptr [[TMP7]], align 1
-; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD4:%.*]] = load <16 x i8>, ptr [[TMP8]], align 1
-; CHECK-NOI8MM-NEXT:    [[TMP9:%.*]] = sext <16 x i8> [[WIDE_LOAD3]] to <16 x i32>
-; CHECK-NOI8MM-NEXT:    [[TMP10:%.*]] = sext <16 x i8> [[WIDE_LOAD4]] to <16 x i32>
-; CHECK-NOI8MM-NEXT:    [[TMP11:%.*]] = mul <16 x i32> [[TMP9]], [[TMP4]]
-; CHECK-NOI8MM-NEXT:    [[TMP12:%.*]] = mul <16 x i32> [[TMP10]], [[TMP5]]
-; CHECK-NOI8MM-NEXT:    [[PARTIAL_REDUCE]] = call <4 x i32> @llvm.experimental.vector.partial.reduce.add.v4i32.v16i32(<4 x i32> [[VEC_PHI]], <16 x i32> [[TMP11]])
-; CHECK-NOI8MM-NEXT:    [[PARTIAL_REDUCE5]] = call <4 x i32> @llvm.experimental.vector.partial.reduce.add.v4i32.v16i32(<4 x i32> [[VEC_PHI1]], <16 x i32> [[TMP12]])
-; CHECK-NOI8MM-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 32
-; CHECK-NOI8MM-NEXT:    [[TMP13:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1024
-; CHECK-NOI8MM-NEXT:    br i1 [[TMP13]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK-NOI8MM-NEXT:    [[TMP15:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NOI8MM-NEXT:    [[TMP16:%.*]] = mul i64 [[TMP15]], 4
+; CHECK-NOI8MM-NEXT:    [[TMP17:%.*]] = getelementptr i8, ptr [[TMP6]], i64 [[TMP16]]
+; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD3:%.*]] = load <vscale x 4 x i8>, ptr [[TMP7]], align 1
+; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD4:%.*]] = load <vscale x 4 x i8>, ptr [[TMP17]], align 1
+; CHECK-NOI8MM-NEXT:    [[TMP18:%.*]] = sext <vscale x 4 x i8> [[WIDE_LOAD3]] to <vscale x 4 x i32>
+; CHECK-NOI8MM-NEXT:    [[TMP19:%.*]] = sext <vscale x 4 x i8> [[WIDE_LOAD4]] to <vscale x 4 x i32>
+; CHECK-NOI8MM-NEXT:    [[TMP20:%.*]] = mul <vscale x 4 x i32> [[TMP18]], [[TMP11]]
+; CHECK-NOI8MM-NEXT:    [[TMP21:%.*]] = mul <vscale x 4 x i32> [[TMP19]], [[TMP12]]
+; CHECK-NOI8MM-NEXT:    [[TMP22]] = add <vscale x 4 x i32> [[TMP20]], [[VEC_PHI]]
+; CHECK-NOI8MM-NEXT:    [[TMP23]] = add <vscale x 4 x i32> [[TMP21]], [[VEC_PHI1]]
+; CHECK-NOI8MM-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP5]]
+; CHECK-NOI8MM-NEXT:    [[TMP24:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NOI8MM-NEXT:    br i1 [[TMP24]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
 ; CHECK-NOI8MM:       middle.block:
-; CHECK-NOI8MM-NEXT:    [[BIN_RDX:%.*]] = add <4 x i32> [[PARTIAL_REDUCE5]], [[PARTIAL_REDUCE]]
-; CHECK-NOI8MM-NEXT:    [[TMP14:%.*]] = call i32 @llvm.vector.reduce.add.v4i32(<4 x i32> [[BIN_RDX]])
-; CHECK-NOI8MM-NEXT:    br i1 true, label [[FOR_EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK-NOI8MM-NEXT:    [[BIN_RDX:%.*]] = add <vscale x 4 x i32> [[TMP23]], [[TMP22]]
+; CHECK-NOI8MM-NEXT:    [[TMP25:%.*]] = call i32 @llvm.vector.reduce.add.nxv4i32(<vscale x 4 x i32> [[BIN_RDX]])
+; CHECK-NOI8MM-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
+; CHECK-NOI8MM-NEXT:    br i1 [[CMP_N]], label [[FOR_EXIT:%.*]], label [[SCALAR_PH]]
 ; CHECK-NOI8MM:       scalar.ph:
 ;
 entry:
@@ -143,38 +156,51 @@ define i32 @dotp_s_z(ptr %a, ptr %b) #0 {
 ; CHECK-NOI8MM-LABEL: define i32 @dotp_s_z(
 ; CHECK-NOI8MM-SAME: ptr [[A:%.*]], ptr [[B:%.*]]) #[[ATTR0]] {
 ; CHECK-NOI8MM-NEXT:  entry:
+; CHECK-NOI8MM-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NOI8MM-NEXT:    [[TMP13:%.*]] = mul i64 [[TMP0]], 8
 ; CHECK-NOI8MM-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
 ; CHECK-NOI8MM:       vector.ph:
+; CHECK-NOI8MM-NEXT:    [[TMP14:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NOI8MM-NEXT:    [[TMP3:%.*]] = mul i64 [[TMP14]], 8
+; CHECK-NOI8MM-NEXT:    [[N_MOD_VF:%.*]] = urem i64 1024, [[TMP3]]
+; CHECK-NOI8MM-NEXT:    [[N_VEC:%.*]] = sub i64 1024, [[N_MOD_VF]]
+; CHECK-NOI8MM-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NOI8MM-NEXT:    [[TMP5:%.*]] = mul i64 [[TMP4]], 8
 ; CHECK-NOI8MM-NEXT:    br label [[VECTOR_BODY:%.*]]
 ; CHECK-NOI8MM:       vector.body:
 ; CHECK-NOI8MM-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
-; CHECK-NOI8MM-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[PARTIAL_REDUCE:%.*]], [[VECTOR_BODY]] ]
-; CHECK-NOI8MM-NEXT:    [[VEC_PHI1:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[PARTIAL_REDUCE5:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NOI8MM-NEXT:    [[VEC_PHI:%.*]] = phi <vscale x 4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP22:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NOI8MM-NEXT:    [[VEC_PHI1:%.*]] = phi <vscale x 4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP23:%.*]], [[VECTOR_BODY]] ]
 ; CHECK-NOI8MM-NEXT:    [[TMP1:%.*]] = getelementptr i8, ptr [[A]], i64 [[INDEX]]
 ; CHECK-NOI8MM-NEXT:    [[TMP2:%.*]] = getelementptr i8, ptr [[TMP1]], i32 0
-; CHECK-NOI8MM-NEXT:    [[TMP3:%.*]] = getelementptr i8, ptr [[TMP1]], i32 16
-; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD:%.*]] = load <16 x i8>, ptr [[TMP2]], align 1
-; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD2:%.*]] = load <16 x i8>, ptr [[TMP3]], align 1
-; CHECK-NOI8MM-NEXT:    [[TMP4:%.*]] = sext <16 x i8> [[WIDE_LOAD]] to <16 x i32>
-; CHECK-NOI8MM-NEXT:    [[TMP5:%.*]] = sext <16 x i8> [[WIDE_LOAD2]] to <16 x i32>
+; CHECK-NOI8MM-NEXT:    [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NOI8MM-NEXT:    [[TMP9:%.*]] = mul i64 [[TMP8]], 4
+; CHECK-NOI8MM-NEXT:    [[TMP10:%.*]] = getelementptr i8, ptr [[TMP1]], i64 [[TMP9]]
+; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD:%.*]] = load <vscale x 4 x i8>, ptr [[TMP2]], align 1
+; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD2:%.*]] = load <vscale x 4 x i8>, ptr [[TMP10]], align 1
+; CHECK-NOI8MM-NEXT:    [[TMP11:%.*]] = sext <vscale x 4 x i8> [[WIDE_LOAD]] to <vscale x 4 x i32>
+; CHECK-NOI8MM-NEXT:    [[TMP12:%.*]] = sext <vscale x 4 x i8> [[WIDE_LOAD2]] to <vscale x 4 x i32>
 ; CHECK-NOI8MM-NEXT:    [[TMP6:%.*]] = getelementptr i8, ptr [[B]], i64 [[INDEX]]
 ; CHECK-NOI8MM-NEXT:    [[TMP7:%.*]] = getelementptr i8, ptr [[TMP6]], i32 0
-; CHECK-NOI8MM-NEXT:    [[TMP8:%.*]] = getelementptr i8, ptr [[TMP6]], i32 16
-; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD3:%.*]] = load <16 x i8>, ptr [[TMP7]], align 1
-; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD4:%.*]] = load <16 x i8>, ptr [[TMP8]], align 1
-; CHECK-NOI8MM-NEXT:    [[TMP9:%.*]] = zext <16 x i8> [[WIDE_LOAD3]] to <16 x i32>
-; CHECK-NOI8MM-NEXT:    [[TMP10:%.*]] = zext <16 x i8> [[WIDE_LOAD4]] to <16 x i32>
-; CHECK-NOI8MM-NEXT:    [[TMP11:%.*]] = mul <16 x i32> [[TMP9]], [[TMP4]]
-; CHECK-NOI8MM-NEXT:    [[TMP12:%.*]] = mul <16 x i32> [[TMP10]], [[TMP5]]
-; CHECK-NOI8MM-NEXT:    [[PARTIAL_REDUCE]] = call <4 x i32> @llvm.experimental.vector.partial.reduce.add.v4i32.v16i32(<4 x i32> [[VEC_PHI]], <16 x i32> [[TMP11]])
-; CHECK-NOI8MM-NEXT:    [[PARTIAL_REDUCE5]] = call <4 x i32> @llvm.experimental.vector.partial.reduce.add.v4i32.v16i32(<4 x i32> [[VEC_PHI1]], <16 x i32> [[TMP12]])
-; CHECK-NOI8MM-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 32
-; CHECK-NOI8MM-NEXT:    [[TMP13:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1024
-; CHECK-NOI8MM-NEXT:    br i1 [[TMP13]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK-NOI8MM-NEXT:    [[TMP15:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NOI8MM-NEXT:    [[TMP16:%.*]] = mul i64 [[TMP15]], 4
+; CHECK-NOI8MM-NEXT:    [[TMP17:%.*]] = getelementptr i8, ptr [[TMP6]], i64 [[TMP16]]
+; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD3:%.*]] = load <vscale x 4 x i8>, ptr [[TMP7]], align 1
+; CHECK-NOI8MM-NEXT:    [[WIDE_LOAD4:%.*]] = load <vscale x 4 x i8>, ptr [[TMP17]], align 1
+; CHECK-NOI8MM-NEXT:    [[TMP18:%.*]] = zext <vscale x 4 x i8> [[WIDE_LOAD3]] to <vscale x 4 x i32>
+; CHECK-NOI8MM-NEXT:    [[TMP19:%.*]] = zext <vscale x 4 x i8> [[WIDE_LOAD4]] to <vscale x 4 x i32>
+; CHECK-NOI8MM-NEXT:    [[TMP20:%.*]] = mul <vscale x 4 x i32> [[TMP18]], [[TMP11]]
+; CHECK-NOI8MM-NEXT:    [[TMP21:%.*]] = mul <vscale x 4 x i32> [[TMP19]], [[TMP12]]
+; CHECK-NOI8MM-NEXT:    [[TMP22]] = add <vscale x 4 x i32> [[TMP20]], [[VEC_PHI]]
+; CHECK-NOI8MM-NEXT:    [[TMP23]] = add <vscale x 4 x i32> [[TMP21]], [[VEC_PHI1]]
+; CHECK-NOI8MM-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP5]]
+; CHECK-NOI8MM-NEXT:    [[TMP24:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NOI8MM-NEXT:    br i1 [[TMP24]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
 ; CHECK-NOI8MM:       middle.block:
-; CHECK-NOI8MM-NEXT:    [[BIN_RDX:%.*]] = add <4 x i32> [[PARTIAL_REDUCE5]], [[PARTIAL_REDUCE]]
-; CHECK-NOI8MM-NEXT:    [[TMP14:%.*]] = call i32 @llvm.vector.reduce.add.v4i32(<4 x i32> [[BIN_RDX]])
-; CHECK-NOI8MM-NEXT:    br i1 true, label [[FOR_EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK-NOI8MM-NEXT:    [[BIN_RDX:%.*]] = add <vscale x 4 x i32> [[TMP23]], [[TMP22]]
+; CHECK-NOI8MM-NEXT:    [[TMP25:%.*]] = call i32 @llvm.vector.reduce.add.nxv4i32(<vscale x 4 x i32> [[BIN_RDX]])
+; CHECK-NOI8MM-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
+; CHECK-NOI8MM-NEXT:    br i1 [[CMP_N]], label [[FOR_EXIT:%.*]], label [[SCALAR_PH]]
 ; CHECK-NOI8MM:       scalar.ph:
 ;
 entry:



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