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release/20.x: [LV][VPlan] Prevent calculate cost for skiped instructions in precomputeCosts(). (#127966) #128694

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release/20.x: [LV][VPlan] Prevent calculate cost for skiped instructions in precomputeCosts(). (#127966) #128694

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5 changes: 3 additions & 2 deletions llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7239,7 +7239,7 @@ LoopVectorizationPlanner::precomputeCosts(VPlan &Plan, ElementCount VF,
// Collect all exit conditions.
for (BasicBlock *EB : Exiting) {
auto *Term = dyn_cast<BranchInst>(EB->getTerminator());
if (!Term)
if (!Term || CostCtx.skipCostComputation(Term, VF.isVector()))
continue;
if (auto *CondI = dyn_cast<Instruction>(Term->getOperand(0))) {
ExitInstrs.insert(CondI);
Expand All @@ -7259,7 +7259,8 @@ LoopVectorizationPlanner::precomputeCosts(VPlan &Plan, ElementCount VF,
Cost += CondICost;
for (Value *Op : CondI->operands()) {
auto *OpI = dyn_cast<Instruction>(Op);
if (!OpI || any_of(OpI->users(), [&ExitInstrs, this](User *U) {
if (!OpI || CostCtx.skipCostComputation(OpI, VF.isVector()) ||
any_of(OpI->users(), [&ExitInstrs, this](User *U) {
return OrigLoop->contains(cast<Instruction>(U)->getParent()) &&
!ExitInstrs.contains(cast<Instruction>(U));
}))
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124 changes: 124 additions & 0 deletions llvm/test/Transforms/LoopVectorize/X86/cost-model.ll
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Expand Up @@ -1211,6 +1211,130 @@ exit:
ret i32 %or
}

; Check if the vplan-based cost model select same VF to the legacy cost model.
; Reduced from: https://github.com/llvm/llvm-project/issues/115744#issuecomment-2670479463
define i32 @g(i64 %n) {
; CHECK-LABEL: @g(
; CHECK-NEXT: iter.check:
; CHECK-NEXT: [[TMP0:%.*]] = trunc i64 [[N:%.*]] to i32
; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[TMP0]], 1
; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i32 [[TMP1]], 4
; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[VEC_EPILOG_SCALAR_PH:%.*]], label [[VECTOR_SCEVCHECK:%.*]]
; CHECK: vector.scevcheck:
; CHECK-NEXT: [[TMP2:%.*]] = icmp ugt i64 [[N]], 4294967295
; CHECK-NEXT: br i1 [[TMP2]], label [[VEC_EPILOG_SCALAR_PH]], label [[VECTOR_MAIN_LOOP_ITER_CHECK:%.*]]
; CHECK: vector.main.loop.iter.check:
; CHECK-NEXT: [[MIN_ITERS_CHECK1:%.*]] = icmp ult i32 [[TMP1]], 16
; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK1]], label [[VEC_EPILOG_PH:%.*]], label [[VECTOR_PH:%.*]]
; CHECK: vector.ph:
; CHECK-NEXT: [[N_MOD_VF:%.*]] = urem i32 [[TMP1]], 16
; CHECK-NEXT: [[N_VEC:%.*]] = sub i32 [[TMP1]], [[N_MOD_VF]]
; CHECK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[N]], i64 0
; CHECK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
; CHECK: vector.body:
; CHECK-NEXT: [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, [[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[VEC_PHI:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP15:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[VEC_PHI2:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP16:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[VEC_PHI3:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP17:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[VEC_PHI4:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP18:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[STEP_ADD:%.*]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
; CHECK-NEXT: [[STEP_ADD_2:%.*]] = add <4 x i32> [[STEP_ADD]], splat (i32 4)
; CHECK-NEXT: [[STEP_ADD_3:%.*]] = add <4 x i32> [[STEP_ADD_2]], splat (i32 4)
; CHECK-NEXT: [[TMP3:%.*]] = zext <4 x i32> [[VEC_IND]] to <4 x i64>
; CHECK-NEXT: [[TMP4:%.*]] = zext <4 x i32> [[STEP_ADD]] to <4 x i64>
; CHECK-NEXT: [[TMP5:%.*]] = zext <4 x i32> [[STEP_ADD_2]] to <4 x i64>
; CHECK-NEXT: [[TMP6:%.*]] = zext <4 x i32> [[STEP_ADD_3]] to <4 x i64>
; CHECK-NEXT: [[TMP7:%.*]] = icmp eq <4 x i64> [[BROADCAST_SPLAT]], [[TMP3]]
; CHECK-NEXT: [[TMP8:%.*]] = icmp eq <4 x i64> [[BROADCAST_SPLAT]], [[TMP4]]
; CHECK-NEXT: [[TMP9:%.*]] = icmp eq <4 x i64> [[BROADCAST_SPLAT]], [[TMP5]]
; CHECK-NEXT: [[TMP10:%.*]] = icmp eq <4 x i64> [[BROADCAST_SPLAT]], [[TMP6]]
; CHECK-NEXT: [[TMP11:%.*]] = select <4 x i1> [[TMP7]], <4 x i32> zeroinitializer, <4 x i32> splat (i32 2)
; CHECK-NEXT: [[TMP12:%.*]] = select <4 x i1> [[TMP8]], <4 x i32> zeroinitializer, <4 x i32> splat (i32 2)
; CHECK-NEXT: [[TMP13:%.*]] = select <4 x i1> [[TMP9]], <4 x i32> zeroinitializer, <4 x i32> splat (i32 2)
; CHECK-NEXT: [[TMP14:%.*]] = select <4 x i1> [[TMP10]], <4 x i32> zeroinitializer, <4 x i32> splat (i32 2)
; CHECK-NEXT: [[TMP15]] = or <4 x i32> [[TMP11]], [[VEC_PHI]]
; CHECK-NEXT: [[TMP16]] = or <4 x i32> [[TMP12]], [[VEC_PHI2]]
; CHECK-NEXT: [[TMP17]] = or <4 x i32> [[TMP13]], [[VEC_PHI3]]
; CHECK-NEXT: [[TMP18]] = or <4 x i32> [[TMP14]], [[VEC_PHI4]]
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 16
; CHECK-NEXT: [[VEC_IND_NEXT]] = add <4 x i32> [[STEP_ADD_3]], splat (i32 4)
; CHECK-NEXT: [[TMP19:%.*]] = icmp eq i32 [[INDEX_NEXT]], [[N_VEC]]
; CHECK-NEXT: br i1 [[TMP19]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP30:![0-9]+]]
; CHECK: middle.block:
; CHECK-NEXT: [[BIN_RDX:%.*]] = or <4 x i32> [[TMP16]], [[TMP15]]
; CHECK-NEXT: [[BIN_RDX5:%.*]] = or <4 x i32> [[TMP17]], [[BIN_RDX]]
; CHECK-NEXT: [[BIN_RDX6:%.*]] = or <4 x i32> [[TMP18]], [[BIN_RDX5]]
; CHECK-NEXT: [[TMP20:%.*]] = call i32 @llvm.vector.reduce.or.v4i32(<4 x i32> [[BIN_RDX6]])
; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP1]], [[N_VEC]]
; CHECK-NEXT: br i1 [[CMP_N]], label [[EXIT:%.*]], label [[VEC_EPILOG_ITER_CHECK:%.*]]
; CHECK: vec.epilog.iter.check:
; CHECK-NEXT: [[N_VEC_REMAINING:%.*]] = sub i32 [[TMP1]], [[N_VEC]]
; CHECK-NEXT: [[MIN_EPILOG_ITERS_CHECK:%.*]] = icmp ult i32 [[N_VEC_REMAINING]], 4
; CHECK-NEXT: br i1 [[MIN_EPILOG_ITERS_CHECK]], label [[VEC_EPILOG_SCALAR_PH]], label [[VEC_EPILOG_PH]]
; CHECK: vec.epilog.ph:
; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[VECTOR_MAIN_LOOP_ITER_CHECK]] ]
; CHECK-NEXT: [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP20]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[VECTOR_MAIN_LOOP_ITER_CHECK]] ]
; CHECK-NEXT: [[N_MOD_VF7:%.*]] = urem i32 [[TMP1]], 4
; CHECK-NEXT: [[N_VEC8:%.*]] = sub i32 [[TMP1]], [[N_MOD_VF7]]
; CHECK-NEXT: [[DOTSPLATINSERT:%.*]] = insertelement <4 x i32> poison, i32 [[BC_RESUME_VAL]], i64 0
; CHECK-NEXT: [[DOTSPLAT:%.*]] = shufflevector <4 x i32> [[DOTSPLATINSERT]], <4 x i32> poison, <4 x i32> zeroinitializer
; CHECK-NEXT: [[INDUCTION:%.*]] = add <4 x i32> [[DOTSPLAT]], <i32 0, i32 1, i32 2, i32 3>
; CHECK-NEXT: [[TMP21:%.*]] = insertelement <4 x i32> zeroinitializer, i32 [[BC_MERGE_RDX]], i32 0
; CHECK-NEXT: [[BROADCAST_SPLATINSERT13:%.*]] = insertelement <4 x i64> poison, i64 [[N]], i64 0
; CHECK-NEXT: [[BROADCAST_SPLAT14:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT13]], <4 x i64> poison, <4 x i32> zeroinitializer
; CHECK-NEXT: br label [[VEC_EPILOG_VECTOR_BODY:%.*]]
; CHECK: vec.epilog.vector.body:
; CHECK-NEXT: [[INDEX9:%.*]] = phi i32 [ [[BC_RESUME_VAL]], [[VEC_EPILOG_PH]] ], [ [[INDEX_NEXT15:%.*]], [[VEC_EPILOG_VECTOR_BODY]] ]
; CHECK-NEXT: [[VEC_IND10:%.*]] = phi <4 x i32> [ [[INDUCTION]], [[VEC_EPILOG_PH]] ], [ [[VEC_IND_NEXT11:%.*]], [[VEC_EPILOG_VECTOR_BODY]] ]
; CHECK-NEXT: [[VEC_PHI12:%.*]] = phi <4 x i32> [ [[TMP21]], [[VEC_EPILOG_PH]] ], [ [[TMP25:%.*]], [[VEC_EPILOG_VECTOR_BODY]] ]
; CHECK-NEXT: [[TMP22:%.*]] = zext <4 x i32> [[VEC_IND10]] to <4 x i64>
; CHECK-NEXT: [[TMP23:%.*]] = icmp eq <4 x i64> [[BROADCAST_SPLAT14]], [[TMP22]]
; CHECK-NEXT: [[TMP24:%.*]] = select <4 x i1> [[TMP23]], <4 x i32> zeroinitializer, <4 x i32> splat (i32 2)
; CHECK-NEXT: [[TMP25]] = or <4 x i32> [[TMP24]], [[VEC_PHI12]]
; CHECK-NEXT: [[INDEX_NEXT15]] = add nuw i32 [[INDEX9]], 4
; CHECK-NEXT: [[VEC_IND_NEXT11]] = add <4 x i32> [[VEC_IND10]], splat (i32 4)
; CHECK-NEXT: [[TMP26:%.*]] = icmp eq i32 [[INDEX_NEXT15]], [[N_VEC8]]
; CHECK-NEXT: br i1 [[TMP26]], label [[VEC_EPILOG_MIDDLE_BLOCK:%.*]], label [[VEC_EPILOG_VECTOR_BODY]], !llvm.loop [[LOOP31:![0-9]+]]
; CHECK: vec.epilog.middle.block:
; CHECK-NEXT: [[TMP27:%.*]] = call i32 @llvm.vector.reduce.or.v4i32(<4 x i32> [[TMP25]])
; CHECK-NEXT: [[CMP_N16:%.*]] = icmp eq i32 [[TMP1]], [[N_VEC8]]
; CHECK-NEXT: br i1 [[CMP_N16]], label [[EXIT]], label [[VEC_EPILOG_SCALAR_PH]]
; CHECK: vec.epilog.scalar.ph:
; CHECK-NEXT: [[BC_RESUME_VAL17:%.*]] = phi i32 [ [[N_VEC8]], [[VEC_EPILOG_MIDDLE_BLOCK]] ], [ [[N_VEC]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[VECTOR_SCEVCHECK]] ], [ 0, [[ITER_CHECK:%.*]] ]
; CHECK-NEXT: [[BC_MERGE_RDX18:%.*]] = phi i32 [ [[TMP27]], [[VEC_EPILOG_MIDDLE_BLOCK]] ], [ [[TMP20]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[VECTOR_SCEVCHECK]] ], [ 0, [[ITER_CHECK]] ]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV:%.*]] = phi i32 [ [[BC_RESUME_VAL17]], [[VEC_EPILOG_SCALAR_PH]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
; CHECK-NEXT: [[SELECT:%.*]] = phi i32 [ [[BC_MERGE_RDX18]], [[VEC_EPILOG_SCALAR_PH]] ], [ [[SELECT_NEXT:%.*]], [[LOOP]] ]
; CHECK-NEXT: [[IV_WIDEN:%.*]] = zext i32 [[IV]] to i64
; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i64 [[N]], [[IV_WIDEN]]
; CHECK-NEXT: [[SELECT_I:%.*]] = select i1 [[EXITCOND]], i32 0, i32 2
; CHECK-NEXT: [[SELECT_NEXT]] = or i32 [[SELECT_I]], [[SELECT]]
; CHECK-NEXT: [[IV_NEXT]] = add i32 [[IV]], 1
; CHECK-NEXT: br i1 [[EXITCOND]], label [[EXIT]], label [[LOOP]], !llvm.loop [[LOOP32:![0-9]+]]
; CHECK: exit:
; CHECK-NEXT: [[SELECT_NEXT_LCSSA:%.*]] = phi i32 [ [[SELECT_NEXT]], [[LOOP]] ], [ [[TMP20]], [[MIDDLE_BLOCK]] ], [ [[TMP27]], [[VEC_EPILOG_MIDDLE_BLOCK]] ]
; CHECK-NEXT: ret i32 [[SELECT_NEXT_LCSSA]]
;
entry:
br label %loop

loop:
%iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
%select = phi i32 [ 0, %entry ], [ %select.next, %loop ]
%iv.widen = zext i32 %iv to i64
%exitcond = icmp eq i64 %n, %iv.widen
%select.i = select i1 %exitcond, i32 0, i32 2
%select.next = or i32 %select.i, %select
%iv.next = add i32 %iv, 1
br i1 %exitcond, label %exit, label %loop

exit:
ret i32 %select.next
}

declare void @llvm.assume(i1 noundef) #0

attributes #0 = { "target-cpu"="penryn" }
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