[PATCH] D101477: [SLP]Fix the crash on cost calculation if non-compatible vectors shuffled.

[Alexey Bataev via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
ABataev marked an inline comment as done.
Closed by commit rGa3fd82c28987: [SLP]Fix the crash on cost calculation if non-compatible vectors shuffled. (authored by ABataev).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D101477/new/

https://reviews.llvm.org/D101477

Files:
  llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
  llvm/test/Transforms/SLPVectorizer/AMDGPU/crash_extract_subvector_cost.ll


Index: llvm/test/Transforms/SLPVectorizer/AMDGPU/crash_extract_subvector_cost.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/SLPVectorizer/AMDGPU/crash_extract_subvector_cost.ll
@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -slp-vectorizer %s | FileCheck %s
+
+define <2 x i16> @uadd_sat_v9i16_combine_vi16(<9 x i16> %arg0, <9 x i16> %arg1) {
+; CHECK-LABEL: @uadd_sat_v9i16_combine_vi16(
+; CHECK-NEXT:  bb:
+; CHECK-NEXT:    [[ARG0_1:%.*]] = extractelement <9 x i16> undef, i64 7
+; CHECK-NEXT:    [[ARG0_2:%.*]] = extractelement <9 x i16> [[ARG0:%.*]], i64 8
+; CHECK-NEXT:    [[ARG1_1:%.*]] = extractelement <9 x i16> [[ARG1:%.*]], i64 7
+; CHECK-NEXT:    [[ARG1_2:%.*]] = extractelement <9 x i16> [[ARG1]], i64 8
+; CHECK-NEXT:    [[TMP0:%.*]] = insertelement <2 x i16> poison, i16 [[ARG0_1]], i32 0
+; CHECK-NEXT:    [[TMP1:%.*]] = insertelement <2 x i16> [[TMP0]], i16 [[ARG0_2]], i32 1
+; CHECK-NEXT:    [[TMP2:%.*]] = insertelement <2 x i16> poison, i16 [[ARG1_1]], i32 0
+; CHECK-NEXT:    [[TMP3:%.*]] = insertelement <2 x i16> [[TMP2]], i16 [[ARG1_2]], i32 1
+; CHECK-NEXT:    [[TMP4:%.*]] = call <2 x i16> @llvm.uadd.sat.v2i16(<2 x i16> [[TMP1]], <2 x i16> [[TMP3]])
+; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <2 x i16> [[TMP4]], i32 0
+; CHECK-NEXT:    [[INS_1:%.*]] = insertelement <2 x i16> undef, i16 [[TMP5]], i64 0
+; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <2 x i16> [[TMP4]], i32 1
+; CHECK-NEXT:    [[INS_2:%.*]] = insertelement <2 x i16> [[INS_1]], i16 [[TMP6]], i64 1
+; CHECK-NEXT:    ret <2 x i16> [[INS_2]]
+;
+bb:
+  %arg0.1 = extractelement <9 x i16> undef, i64 7
+  %arg0.2 = extractelement <9 x i16> %arg0, i64 8
+  %arg1.1 = extractelement <9 x i16> %arg1, i64 7
+  %arg1.2 = extractelement <9 x i16> %arg1, i64 8
+  %add.1 = call i16 @llvm.uadd.sat.i16(i16 %arg0.1, i16 %arg1.1)
+  %add.2 = call i16 @llvm.uadd.sat.i16(i16 %arg0.2, i16 %arg1.2)
+  %ins.1 = insertelement <2 x i16> undef, i16 %add.1, i64 0
+  %ins.2 = insertelement <2 x i16> %ins.1, i16 %add.2, i64 1
+  ret <2 x i16> %ins.2
+}
+
+declare i16 @llvm.uadd.sat.i16(i16, i16) #0
+attributes #0 = { nounwind readnone speculatable willreturn }
Index: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -3589,13 +3589,27 @@
     for (const auto &Data : ExtractVectorsTys) {
       auto *EEVTy = cast<FixedVectorType>(Data.first->getType());
       unsigned NumElts = VecTy->getNumElements();
-      if (TTIRef.getNumberOfParts(EEVTy) > TTIRef.getNumberOfParts(VecTy))
-        Cost += TTIRef.getShuffleCost(TargetTransformInfo::SK_ExtractSubvector,
-                                      EEVTy, None,
-                                      (Data.second / NumElts) * NumElts, VecTy);
-      else
+      if (TTIRef.getNumberOfParts(EEVTy) > TTIRef.getNumberOfParts(VecTy)) {
+        unsigned Idx = (Data.second / NumElts) * NumElts;
+        unsigned EENumElts = EEVTy->getNumElements();
+        if (Idx + NumElts <= EENumElts) {
+          Cost +=
+              TTIRef.getShuffleCost(TargetTransformInfo::SK_ExtractSubvector,
+                                    EEVTy, None, Idx, VecTy);
+        } else {
+          // Need to round up the subvector type vectorization factor to avoid a
+          // crash in cost model functions. Make SubVT so that Idx + VF of SubVT
+          // <= EENumElts.
+          auto *SubVT =
+              FixedVectorType::get(VecTy->getElementType(), EENumElts - Idx);
+          Cost +=
+              TTIRef.getShuffleCost(TargetTransformInfo::SK_ExtractSubvector,
+                                    EEVTy, None, Idx, SubVT);
+        }
+      } else {
         Cost += TTIRef.getShuffleCost(TargetTransformInfo::SK_InsertSubvector,
                                       VecTy, None, 0, EEVTy);
+      }
     }
   };
   if (E->State == TreeEntry::NeedToGather) {


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