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clang-p2996/llvm/test/Transforms/LoopVectorize/X86/pr35432.ll
Sjoerd Meijer 9529597cf4 Recommit #2: "[LV] Induction Variable does not remain scalar under tail-folding." 
This was reverted because of a miscompilation. At closer inspection, the
problem was actually visible in a changed llvm regression test too. This
one-line follow up fix/recommit will splat the IV, which is what we are trying
to avoid if unnecessary in general, if tail-folding is requested even if all
users are scalar instructions after vectorisation. Because with tail-folding,
the splat IV will be used by the predicate of the masked loads/stores
instructions. The previous version omitted this, which caused the
miscompilation. The original commit message was:

If tail-folding of the scalar remainder loop is applied, the primary induction
variable is splat to a vector and used by the masked load/store vector
instructions, thus the IV does not remain scalar. Because we now mark
that the IV does not remain scalar for these cases, we don't emit the vector IV
if it is not used. Thus, the vectoriser produces less dead code.

Thanks to Ayal Zaks for the direction how to fix this.
2020-05-13 13:50:09 +01:00

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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -loop-vectorize -mtriple=x86_64-unknown-linux-gnu -S < %s | FileCheck %s
; The test checks that there is no assert caused by issue described in PR35432
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@a = common local_unnamed_addr global [192 x [192 x i32]] zeroinitializer, align 16
; Function Attrs: nounwind uwtable
define i32 @main() local_unnamed_addr #0 {
; CHECK-LABEL: @main(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[I:%.*]] = alloca i32, align 4
; CHECK-NEXT: [[S:%.*]] = alloca i16, align 2
; CHECK-NEXT: [[TMP0:%.*]] = bitcast i32* [[I]] to i8*
; CHECK-NEXT: call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull [[TMP0]])
; CHECK-NEXT: store i32 0, i32* [[I]], align 4
; CHECK-NEXT: [[TMP1:%.*]] = bitcast i16* [[S]] to i8*
; CHECK-NEXT: call void @llvm.lifetime.start.p0i8(i64 2, i8* nonnull [[TMP1]])
; CHECK-NEXT: [[CALL:%.*]] = call i32 (i32*, ...) bitcast (i32 (...)* @goo to i32 (i32*, ...)*)(i32* nonnull [[I]])
; CHECK-NEXT: [[TMP2:%.*]] = load i32, i32* [[I]], align 4
; CHECK-NEXT: [[STOREMERGE6:%.*]] = trunc i32 [[TMP2]] to i16
; CHECK-NEXT: store i16 [[STOREMERGE6]], i16* [[S]], align 2
; CHECK-NEXT: [[CONV17:%.*]] = and i32 [[TMP2]], 65472
; CHECK-NEXT: [[CMP8:%.*]] = icmp eq i32 [[CONV17]], 0
; CHECK-NEXT: br i1 [[CMP8]], label [[FOR_BODY_LR_PH:%.*]], label [[FOR_END12:%.*]]
; CHECK: for.body.lr.ph:
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[STOREMERGE_IN9:%.*]] = phi i32 [ [[TMP2]], [[FOR_BODY_LR_PH]] ], [ [[ADD:%.*]], [[FOR_INC9:%.*]] ]
; CHECK-NEXT: [[CONV52:%.*]] = and i32 [[STOREMERGE_IN9]], 255
; CHECK-NEXT: [[CMP63:%.*]] = icmp ult i32 [[TMP2]], [[CONV52]]
; CHECK-NEXT: br i1 [[CMP63]], label [[FOR_BODY8_LR_PH:%.*]], label [[FOR_INC9]]
; CHECK: for.body8.lr.ph:
; CHECK-NEXT: [[CONV3:%.*]] = trunc i32 [[STOREMERGE_IN9]] to i8
; CHECK-NEXT: [[DOTPROMOTED:%.*]] = load i32, i32* getelementptr inbounds ([192 x [192 x i32]], [192 x [192 x i32]]* @a, i64 0, i64 0, i64 0), align 16
; CHECK-NEXT: [[TMP3:%.*]] = add i8 [[CONV3]], -1
; CHECK-NEXT: [[TMP4:%.*]] = zext i8 [[TMP3]] to i32
; CHECK-NEXT: [[TMP5:%.*]] = add i32 [[TMP4]], 1
; CHECK-NEXT: [[TMP6:%.*]] = icmp ult i32 [[TMP2]], [[TMP4]]
; CHECK-NEXT: [[UMIN:%.*]] = select i1 [[TMP6]], i32 [[TMP2]], i32 [[TMP4]]
; CHECK-NEXT: [[TMP7:%.*]] = sub i32 [[TMP5]], [[UMIN]]
; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i32 [[TMP7]], 8
; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_SCEVCHECK:%.*]]
; CHECK: vector.scevcheck:
; CHECK-NEXT: [[TMP8:%.*]] = add i8 [[CONV3]], -1
; CHECK-NEXT: [[TMP9:%.*]] = zext i8 [[TMP8]] to i32
; CHECK-NEXT: [[TMP10:%.*]] = icmp ult i32 [[TMP2]], [[TMP9]]
; CHECK-NEXT: [[UMIN1:%.*]] = select i1 [[TMP10]], i32 [[TMP2]], i32 [[TMP9]]
; CHECK-NEXT: [[TMP11:%.*]] = sub i32 [[TMP9]], [[UMIN1]]
; CHECK-NEXT: [[TMP12:%.*]] = trunc i32 [[TMP11]] to i8
; CHECK-NEXT: [[MUL:%.*]] = call { i8, i1 } @llvm.umul.with.overflow.i8(i8 1, i8 [[TMP12]])
; CHECK-NEXT: [[MUL_RESULT:%.*]] = extractvalue { i8, i1 } [[MUL]], 0
; CHECK-NEXT: [[MUL_OVERFLOW:%.*]] = extractvalue { i8, i1 } [[MUL]], 1
; CHECK-NEXT: [[TMP13:%.*]] = add i8 [[TMP8]], [[MUL_RESULT]]
; CHECK-NEXT: [[TMP14:%.*]] = sub i8 [[TMP8]], [[MUL_RESULT]]
; CHECK-NEXT: [[TMP15:%.*]] = icmp ugt i8 [[TMP14]], [[TMP8]]
; CHECK-NEXT: [[TMP16:%.*]] = icmp ult i8 [[TMP13]], [[TMP8]]
; CHECK-NEXT: [[TMP17:%.*]] = select i1 true, i1 [[TMP15]], i1 [[TMP16]]
; CHECK-NEXT: [[TMP18:%.*]] = icmp ugt i32 [[TMP11]], 255
; CHECK-NEXT: [[TMP19:%.*]] = or i1 [[TMP17]], [[TMP18]]
; CHECK-NEXT: [[TMP20:%.*]] = or i1 [[TMP19]], [[MUL_OVERFLOW]]
; CHECK-NEXT: [[TMP21:%.*]] = or i1 false, [[TMP20]]
; CHECK-NEXT: br i1 [[TMP21]], label [[SCALAR_PH]], label [[VECTOR_PH:%.*]]
; CHECK: vector.ph:
; CHECK-NEXT: [[N_MOD_VF:%.*]] = urem i32 [[TMP7]], 8
; CHECK-NEXT: [[N_VEC:%.*]] = sub i32 [[TMP7]], [[N_MOD_VF]]
; CHECK-NEXT: [[CAST_CRD:%.*]] = trunc i32 [[N_VEC]] to i8
; CHECK-NEXT: [[IND_END:%.*]] = sub i8 [[CONV3]], [[CAST_CRD]]
; CHECK-NEXT: [[TMP22:%.*]] = insertelement <4 x i32> zeroinitializer, i32 [[DOTPROMOTED]], i32 0
; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
; CHECK: vector.body:
; CHECK-NEXT: [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[VEC_PHI:%.*]] = phi <4 x i32> [ [[TMP22]], [[VECTOR_PH]] ], [ [[TMP26:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[VEC_PHI2:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP27:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[TMP23:%.*]] = trunc i32 [[INDEX]] to i8
; CHECK-NEXT: [[OFFSET_IDX:%.*]] = sub i8 [[CONV3]], [[TMP23]]
; CHECK-NEXT: [[TMP24:%.*]] = add i8 [[OFFSET_IDX]], 0
; CHECK-NEXT: [[TMP25:%.*]] = add i8 [[OFFSET_IDX]], -4
; CHECK-NEXT: [[TMP26]] = add <4 x i32> [[VEC_PHI]], <i32 1, i32 1, i32 1, i32 1>
; CHECK-NEXT: [[TMP27]] = add <4 x i32> [[VEC_PHI2]], <i32 1, i32 1, i32 1, i32 1>
; CHECK-NEXT: [[TMP28:%.*]] = add i8 [[TMP24]], -1
; CHECK-NEXT: [[TMP29:%.*]] = add i8 [[TMP25]], -1
; CHECK-NEXT: [[TMP30:%.*]] = zext i8 [[TMP28]] to i32
; CHECK-NEXT: [[TMP31:%.*]] = zext i8 [[TMP29]] to i32
; CHECK-NEXT: [[INDEX_NEXT]] = add i32 [[INDEX]], 8
; CHECK-NEXT: [[TMP32:%.*]] = icmp eq i32 [[INDEX_NEXT]], [[N_VEC]]
; CHECK-NEXT: br i1 [[TMP32]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop !0
; CHECK: middle.block:
; CHECK-NEXT: [[BIN_RDX:%.*]] = add <4 x i32> [[TMP27]], [[TMP26]]
; CHECK-NEXT: [[RDX_SHUF:%.*]] = shufflevector <4 x i32> [[BIN_RDX]], <4 x i32> undef, <4 x i32> <i32 2, i32 3, i32 undef, i32 undef>
; CHECK-NEXT: [[BIN_RDX3:%.*]] = add <4 x i32> [[BIN_RDX]], [[RDX_SHUF]]
; CHECK-NEXT: [[RDX_SHUF4:%.*]] = shufflevector <4 x i32> [[BIN_RDX3]], <4 x i32> undef, <4 x i32> <i32 1, i32 undef, i32 undef, i32 undef>
; CHECK-NEXT: [[BIN_RDX5:%.*]] = add <4 x i32> [[BIN_RDX3]], [[RDX_SHUF4]]
; CHECK-NEXT: [[TMP33:%.*]] = extractelement <4 x i32> [[BIN_RDX5]], i32 0
; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP7]], [[N_VEC]]
; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_COND4_FOR_INC9_CRIT_EDGE:%.*]], label [[SCALAR_PH]]
; CHECK: scalar.ph:
; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i8 [ [[IND_END]], [[MIDDLE_BLOCK]] ], [ [[CONV3]], [[FOR_BODY8_LR_PH]] ], [ [[CONV3]], [[VECTOR_SCEVCHECK]] ]
; CHECK-NEXT: [[BC_MERGE_RDX:%.*]] = phi i32 [ [[DOTPROMOTED]], [[FOR_BODY8_LR_PH]] ], [ [[DOTPROMOTED]], [[VECTOR_SCEVCHECK]] ], [ [[TMP33]], [[MIDDLE_BLOCK]] ]
; CHECK-NEXT: br label [[FOR_BODY8:%.*]]
; CHECK: for.body8:
; CHECK-NEXT: [[INC5:%.*]] = phi i32 [ [[BC_MERGE_RDX]], [[SCALAR_PH]] ], [ [[INC:%.*]], [[FOR_BODY8]] ]
; CHECK-NEXT: [[C_04:%.*]] = phi i8 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[DEC:%.*]], [[FOR_BODY8]] ]
; CHECK-NEXT: [[INC]] = add i32 [[INC5]], 1
; CHECK-NEXT: [[DEC]] = add i8 [[C_04]], -1
; CHECK-NEXT: [[CONV5:%.*]] = zext i8 [[DEC]] to i32
; CHECK-NEXT: [[CMP6:%.*]] = icmp ult i32 [[TMP2]], [[CONV5]]
; CHECK-NEXT: br i1 [[CMP6]], label [[FOR_BODY8]], label [[FOR_COND4_FOR_INC9_CRIT_EDGE]], !llvm.loop !2
; CHECK: for.cond4.for.inc9_crit_edge:
; CHECK-NEXT: [[INC_LCSSA:%.*]] = phi i32 [ [[INC]], [[FOR_BODY8]] ], [ [[TMP33]], [[MIDDLE_BLOCK]] ]
; CHECK-NEXT: store i32 [[INC_LCSSA]], i32* getelementptr inbounds ([192 x [192 x i32]], [192 x [192 x i32]]* @a, i64 0, i64 0, i64 0), align 16
; CHECK-NEXT: br label [[FOR_INC9]]
; CHECK: for.inc9:
; CHECK-NEXT: [[CONV10:%.*]] = and i32 [[STOREMERGE_IN9]], 65535
; CHECK-NEXT: [[ADD]] = add nuw nsw i32 [[CONV10]], 1
; CHECK-NEXT: [[CONV1:%.*]] = and i32 [[ADD]], 65472
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[CONV1]], 0
; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_COND_FOR_END12_CRIT_EDGE:%.*]]
; CHECK: for.cond.for.end12_crit_edge:
; CHECK-NEXT: [[ADD_LCSSA:%.*]] = phi i32 [ [[ADD]], [[FOR_INC9]] ]
; CHECK-NEXT: [[STOREMERGE:%.*]] = trunc i32 [[ADD_LCSSA]] to i16
; CHECK-NEXT: store i16 [[STOREMERGE]], i16* [[S]], align 2
; CHECK-NEXT: br label [[FOR_END12]]
; CHECK: for.end12:
; CHECK-NEXT: [[CALL13:%.*]] = call i32 (i16*, ...) bitcast (i32 (...)* @foo to i32 (i16*, ...)*)(i16* nonnull [[S]])
; CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 2, i8* nonnull [[TMP1]])
; CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull [[TMP0]])
; CHECK-NEXT: ret i32 0
;
entry:
%i = alloca i32, align 4
%s = alloca i16, align 2
%0 = bitcast i32* %i to i8*
call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %0) #3
store i32 0, i32* %i, align 4
%1 = bitcast i16* %s to i8*
call void @llvm.lifetime.start.p0i8(i64 2, i8* nonnull %1) #3
%call = call i32 (i32*, ...) bitcast (i32 (...)* @goo to i32 (i32*, ...)*)(i32* nonnull %i) #3
%2 = load i32, i32* %i, align 4
%storemerge6 = trunc i32 %2 to i16
store i16 %storemerge6, i16* %s, align 2
%conv17 = and i32 %2, 65472
%cmp8 = icmp eq i32 %conv17, 0
br i1 %cmp8, label %for.body.lr.ph, label %for.end12
for.body.lr.ph: ; preds = %entry
br label %for.body
for.body: ; preds = %for.body.lr.ph, %for.inc9
%storemerge.in9 = phi i32 [ %2, %for.body.lr.ph ], [ %add, %for.inc9 ]
%conv52 = and i32 %storemerge.in9, 255
%cmp63 = icmp ult i32 %2, %conv52
br i1 %cmp63, label %for.body8.lr.ph, label %for.inc9
for.body8.lr.ph: ; preds = %for.body
%conv3 = trunc i32 %storemerge.in9 to i8
%.promoted = load i32, i32* getelementptr inbounds ([192 x [192 x i32]], [192 x [192 x i32]]* @a, i64 0, i64 0, i64 0), align 16
br label %for.body8
for.body8: ; preds = %for.body8.lr.ph, %for.body8
%inc5 = phi i32 [ %.promoted, %for.body8.lr.ph ], [ %inc, %for.body8 ]
%c.04 = phi i8 [ %conv3, %for.body8.lr.ph ], [ %dec, %for.body8 ]
%inc = add i32 %inc5, 1
%dec = add i8 %c.04, -1
%conv5 = zext i8 %dec to i32
%cmp6 = icmp ult i32 %2, %conv5
br i1 %cmp6, label %for.body8, label %for.cond4.for.inc9_crit_edge
for.cond4.for.inc9_crit_edge: ; preds = %for.body8
%inc.lcssa = phi i32 [ %inc, %for.body8 ]
store i32 %inc.lcssa, i32* getelementptr inbounds ([192 x [192 x i32]], [192 x [192 x i32]]* @a, i64 0, i64 0, i64 0), align 16
br label %for.inc9
for.inc9: ; preds = %for.cond4.for.inc9_crit_edge, %for.body
%conv10 = and i32 %storemerge.in9, 65535
%add = add nuw nsw i32 %conv10, 1
%conv1 = and i32 %add, 65472
%cmp = icmp eq i32 %conv1, 0
br i1 %cmp, label %for.body, label %for.cond.for.end12_crit_edge
for.cond.for.end12_crit_edge: ; preds = %for.inc9
%add.lcssa = phi i32 [ %add, %for.inc9 ]
%storemerge = trunc i32 %add.lcssa to i16
store i16 %storemerge, i16* %s, align 2
br label %for.end12
for.end12: ; preds = %for.cond.for.end12_crit_edge, %entry
%call13 = call i32 (i16*, ...) bitcast (i32 (...)* @foo to i32 (i16*, ...)*)(i16* nonnull %s) #3
call void @llvm.lifetime.end.p0i8(i64 2, i8* nonnull %1) #3
call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %0) #3
ret i32 0
}
; Function Attrs: argmemonly nounwind
declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #1
declare i32 @goo(...) local_unnamed_addr #2
declare i32 @foo(...) local_unnamed_addr #2
; Function Attrs: argmemonly nounwind
declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #1
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