8c6658aca6
When a recipe can be safely sunk and all of its users are outside the vector loop region in the same dedicated exit block, the recipe does not need to be executed on every iteration. This patch extends the VPlan-based LICM (Loop Invariant Code Motion) to also sink such recipes from the vector loop region into the exit block. This reduces redundant computation and improves cost model accuracy. TODO: Support nested loop sinking TODO: Support sinking `VPReplicateRecipe` (requires `replicateByVF` fixes) TODO: Support recipes with multiple defined values (e.g., interleaved loads) TODO: Clone recipes without users to all exit blocks TODO: Support PHI node users by checking incoming value blocks TODO: Support sinking when users are in multiple blocks TODO: Clone recipes when users are on multiple exit paths Co-authored-by: Luke Lau <luke@igalia.com> --------- Co-authored-by: Luke Lau <luke@igalia.com> Co-authored-by: Luke Lau <luke_lau@icloud.com>
41 lines
1.8 KiB
LLVM
41 lines
1.8 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 5
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; RUN: opt -passes=loop-vectorize -S %s | FileCheck %s
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; There could be more than one LCSSA PHIs in loop exit block.
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define i16 @duplicate_lcssa(i16 %val) {
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; CHECK-LABEL: define i16 @duplicate_lcssa(
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; CHECK-SAME: i16 [[VAL:%.*]]) {
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; CHECK-NEXT: [[ENTRY:.*:]]
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; CHECK-NEXT: br label %[[VECTOR_PH:.*]]
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; CHECK: [[VECTOR_PH]]:
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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 i32 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
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; CHECK-NEXT: [[VEC_IND:%.*]] = phi <4 x i16> [ <i16 0, i16 -1, i16 -2, i16 -3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
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; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 4
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; CHECK-NEXT: [[VEC_IND_NEXT]] = add nsw <4 x i16> [[VEC_IND]], splat (i16 -4)
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; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i32 [[INDEX_NEXT]], 65536
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; CHECK-NEXT: br i1 [[TMP1]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
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; CHECK: [[MIDDLE_BLOCK]]:
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; CHECK-NEXT: [[TMP0:%.*]] = sub nsw <4 x i16> [[VEC_IND]], splat (i16 1)
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; CHECK-NEXT: [[VECTOR_RECUR_EXTRACT_FOR_PHI1:%.*]] = extractelement <4 x i16> [[TMP0]], i32 2
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; CHECK-NEXT: br label %[[EXIT:.*]]
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; CHECK: [[EXIT]]:
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; CHECK-NEXT: ret i16 [[VECTOR_RECUR_EXTRACT_FOR_PHI1]]
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;
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entry:
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br label %loop
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loop:
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%iv = phi i16 [ 0, %entry ], [ %iv.next, %loop ]
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%res = phi i16 [ %val, %entry ], [ %iv.next, %loop ]
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%iv.next = sub nsw i16 %iv, 1
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%exit.cond = icmp ne i16 %iv.next, 0
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br i1 %exit.cond, label %loop, label %exit
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exit:
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%lcssa.1 = phi i16 [ %res, %loop ]
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%lcssa.2 = phi i16 [ %res, %loop ]
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ret i16 %lcssa.2
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}
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