0dddf04cab
At the moment, the same VPlan can be used code generation of both the main vector and epilogue vector loop. This can lead to wrong results, if the plan is optimized based on the VF of the main vector loop and then re-used for the epilogue loop. One example where this is problematic is if the scalar loops need to execute at least one iteration, e.g. due to interleave groups. To prevent mis-compiles in the short-term, disable optimizing exit conditions for VPlans when using epilogue vectorization. The proper fix is to avoid re-using the same plan for both loops, which will require support for cloning plans first. Fixes #56319.
50 lines
2.7 KiB
LLVM
50 lines
2.7 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt %s -loop-vectorize -instcombine -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -mtriple=x86_64-unknown-linux-gnu -mattr=avx512vl,avx512dq,avx512bw -S | FileCheck %s
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@bytes = global [128 x i8] zeroinitializer, align 16
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; Make sure we end up with vector code for this loop. We used to try to create
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; a VF=64,UF=4 loop, but the scalar trip count is only 128 so
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; the vector loop was dead code leaving only a scalar remainder.
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define zeroext i8 @sum() {
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; CHECK-LABEL: @sum(
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; CHECK-NEXT: iter.check:
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; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
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; CHECK: vector.body:
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; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[ITER_CHECK:%.*]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
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; CHECK-NEXT: [[VEC_PHI:%.*]] = phi <64 x i8> [ zeroinitializer, [[ITER_CHECK]] ], [ [[TMP4:%.*]], [[VECTOR_BODY]] ]
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; CHECK-NEXT: [[VEC_PHI1:%.*]] = phi <64 x i8> [ zeroinitializer, [[ITER_CHECK]] ], [ [[TMP5:%.*]], [[VECTOR_BODY]] ]
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; CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds [128 x i8], [128 x i8]* @bytes, i64 0, i64 [[INDEX]]
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; CHECK-NEXT: [[TMP1:%.*]] = bitcast i8* [[TMP0]] to <64 x i8>*
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; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <64 x i8>, <64 x i8>* [[TMP1]], align 16
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; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds i8, i8* [[TMP0]], i64 64
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; CHECK-NEXT: [[TMP3:%.*]] = bitcast i8* [[TMP2]] to <64 x i8>*
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; CHECK-NEXT: [[WIDE_LOAD2:%.*]] = load <64 x i8>, <64 x i8>* [[TMP3]], align 16
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; CHECK-NEXT: [[TMP4]] = add <64 x i8> [[WIDE_LOAD]], [[VEC_PHI]]
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; CHECK-NEXT: [[TMP5]] = add <64 x i8> [[WIDE_LOAD2]], [[VEC_PHI1]]
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; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 128
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; CHECK-NEXT: [[TMP6:%.*]] = icmp eq i64 [[INDEX]], 0
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; CHECK-NEXT: br i1 [[TMP6]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
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; CHECK: middle.block:
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; CHECK-NEXT: [[BIN_RDX:%.*]] = add <64 x i8> [[TMP5]], [[TMP4]]
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; CHECK-NEXT: [[TMP7:%.*]] = call i8 @llvm.vector.reduce.add.v64i8(<64 x i8> [[BIN_RDX]])
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; CHECK-NEXT: ret i8 [[TMP7]]
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;
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entry:
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br label %for.body
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for.body: ; preds = %for.body, %entry
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%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
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%r.010 = phi i8 [ 0, %entry ], [ %add, %for.body ]
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%arrayidx = getelementptr inbounds [128 x i8], [128 x i8]* @bytes, i64 0, i64 %indvars.iv
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%0 = load i8, i8* %arrayidx, align 1
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%add = add i8 %0, %r.010
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%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
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%exitcond = icmp eq i64 %indvars.iv.next, 128
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br i1 %exitcond, label %for.end, label %for.body
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for.end: ; preds = %for.body
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%add.lcssa = phi i8 [ %add, %for.body ]
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ret i8 %add.lcssa
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}
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