[PATCH] D154173: [LAA] Add test that shows MaxSafeDepDistBytes is incorrect. NFC.

[Michael Maitland via Phabricator via llvm-commits]

michaelmaitland created this revision.
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This precommit patch shows MaxSafeDepBytesDist is 24 when it should
be 8.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D154173

Files:
  llvm/test/Analysis/LoopAccessAnalysis/max_safe_dep_dist_non_unit_stride.ll


Index: llvm/test/Analysis/LoopAccessAnalysis/max_safe_dep_dist_non_unit_stride.ll
===================================================================
--- /dev/null
+++ llvm/test/Analysis/LoopAccessAnalysis/max_safe_dep_dist_non_unit_stride.ll
@@ -0,0 +1,57 @@
+; RUN: opt -S -disable-output -passes='print<access-info>' < %s 2>&1 | FileCheck %s
+
+; Generated from following C program:
+; void foo(int len, int *a) {
+;   for (int k = 0; k < len; k+=3) {
+;     a[k] = a[k + 4];
+;     a[k+2] = a[k+6];
+;   }
+; }
+define void @foo(i32 noundef signext %len, ptr nocapture noundef %a) {
+; CHECK-LABEL: Loop access info in function 'foo':
+; CHECK-NEXT:  for.body:
+; CHECK-NEXT:    Memory dependences are safe with a maximum dependence distance of 24 bytes
+; CHECK-NEXT:    Dependences:
+; CHECK-NEXT:      BackwardVectorizable:
+; CHECK-NEXT:          store i32 %2, ptr %arrayidx2, align 4 ->
+; CHECK-NEXT:          %4 = load i32, ptr %arrayidx5, align 4
+; CHECK-EMPTY:
+; CHECK-NEXT:    Run-time memory checks:
+; CHECK-NEXT:    Grouped accesses:
+; CHECK-EMPTY:
+; CHECK-NEXT:    Non vectorizable stores to invariant address were not found in loop.
+; CHECK-NEXT:    SCEV assumptions:
+; CHECK-EMPTY:
+; CHECK-NEXT:    Expressions re-written:
+;
+entry:
+  %cmp18 = icmp sgt i32 %len, 0
+  br i1 %cmp18, label %for.body.preheader, label %for.cond.cleanup
+
+for.body.preheader:                               ; preds = %entry
+  %0 = zext i32 %len to i64
+  br label %for.body
+
+for.cond.cleanup.loopexit:                        ; preds = %for.body
+  br label %for.cond.cleanup
+
+for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
+  ret void
+
+for.body:                                         ; preds = %for.body.preheader, %for.body
+  %indvars.iv = phi i64 [ 0, %for.body.preheader ], [ %indvars.iv.next, %for.body ]
+  %1 = add nuw nsw i64 %indvars.iv, 4
+  %arrayidx = getelementptr inbounds i32, ptr %a, i64 %1
+  %2 = load i32, ptr %arrayidx, align 4
+  %arrayidx2 = getelementptr inbounds i32, ptr %a, i64 %indvars.iv
+  store i32 %2, ptr %arrayidx2, align 4
+  %3 = add nuw nsw i64 %indvars.iv, 6
+  %arrayidx5 = getelementptr inbounds i32, ptr %a, i64 %3
+  %4 = load i32, ptr %arrayidx5, align 4
+  %5 = add nuw nsw i64 %indvars.iv, 2
+  %arrayidx8 = getelementptr inbounds i32, ptr %a, i64 %5
+  store i32 %4, ptr %arrayidx8, align 4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 3
+  %cmp = icmp ult i64 %indvars.iv.next, %0
+  br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit
+}


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