[PATCH] D155520: [LV] Complete load groups and release store groups in presence of dependency

[Ayal Zaks via Phabricator via llvm-commits]

Ayal added a comment.

In D155520#4544942 <https://reviews.llvm.org/D155520#4544942>, @Ayal wrote:

> ...
> Having `Dependences.size()` surpass `MaxDependences` calls for an extensive testcase, given the latter defaults to 100.
> An alternative is to reduce this threshold by setting `max-dependences` thereby helping to produce a simpler minimal testcase.

The extensive test reproducer depends on current default value of MaxDependences.
How about also adding a minimal testcase such as something like:

  ; RUN: opt -passes=loop-vectorize -force-vector-width=4 -force-vector-interleave=1 -enable-interleaved-mem-accesses=true --max-dependences=0 -S %s | FileCheck %s
  target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
  
  define void @three_interleaved_stores(ptr %arr) {
  ; CHECK-LABEL: define void @three_interleaved_stores
  ; CHECK:   store <12 x i8>
  entry:
    br label %loop
  
  loop:
    %i = phi i64 [ 0, %entry ], [ %i.next, %loop ]
    %i.plus.1 = add nuw nsw i64 %i, 1
    %i.plus.2 = add nuw nsw i64 %i, 2
    %gep.i.plus.0 = getelementptr inbounds i8, ptr %arr, i64 %i
    %gep.i.plus.1 = getelementptr inbounds i8, ptr %arr, i64 %i.plus.1
    %gep.i.plus.2 = getelementptr inbounds i8, ptr %arr, i64 %i.plus.2
    store i8 1, ptr %gep.i.plus.0
    store i8 1, ptr %gep.i.plus.1
    store i8 1, ptr %gep.i.plus.2
    %i.next = add nuw nsw i64 %i, 3
    %icmp = icmp ugt i64 %i, 1032
    br i1 %icmp, label %exit, label %loop
  
  exit:
    ret void
  }



================
Comment at: llvm/test/Transforms/LoopVectorize/interleaved-accesses-use-after-free.ll:27
+; CHECK: Too many dependences, stopped recording
+; If too many dependences are recorded, LoopAccessAnalysis just conservatively
+; returns true for any pair of instructions compared (even those belonging to
----------------



================
Comment at: llvm/test/Transforms/LoopVectorize/interleaved-accesses-use-after-free.ll:30-31
+; the same store group). This tests make sure that we do not incorrectly release
+; a store group which had no dependences between its members, even if we have
+; too many dependences recorded.
+
----------------



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https://reviews.llvm.org/D155520