64 lines
2.3 KiB
LLVM
64 lines
2.3 KiB
LLVM
; RUN: opt -passes='loop-vectorize' -debug -S < %s 2>&1 | FileCheck %s
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; REQUIRES: asserts
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; This checks we don't crash when the inner loop we're trying to vectorize
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; is a SCEV AddRec with respect to an outer loop.
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; In this case, the problematic PHI is:
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; %0 = phi i32 [ undef, %for.cond1.preheader ], [ %inc54, %for.body3 ]
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; Since %inc54 is the IV of the outer loop, and %0 equivalent to it,
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; we get the situation described above.
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; Code that leads to this situation can look something like:
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;
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; int a, b[1], c;
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; void fn1 ()
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; {
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; for (; c; c++)
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; for (a = 0; a; a++)
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; b[c] = 4;
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; }
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;
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; The PHI is an artifact of the register promotion of c.
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; Note that we can no longer get the vectorizer to actually see such PHIs,
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; because LV now simplifies the loop internally, but the test is still
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; useful as a regression test, and in case loop-simplify behavior changes.
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@c = external global i32, align 4
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@a = external global i32, align 4
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@b = external global [1 x i32], align 4
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; We can vectorize this loop because we are storing an invariant value into an
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; invariant address.
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; CHECK: LV: We can vectorize this loop!
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; CHECK-LABEL: @test
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define void @test() {
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entry:
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%a.promoted2 = load i32, i32* @a, align 1
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%c.promoted = load i32, i32* @c, align 1
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br label %for.cond1.preheader
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for.cond1.preheader: ; preds = %for.cond1.for.inc4_crit_edge, %entry
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%inc54 = phi i32 [ %inc5, %for.cond1.for.inc4_crit_edge ], [ %c.promoted, %entry ]
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%inc.lcssa3 = phi i32 [ %inc.lcssa, %for.cond1.for.inc4_crit_edge ], [ %a.promoted2, %entry ]
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br label %for.body3
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for.body3: ; preds = %for.body3, %for.cond1.preheader
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%inc1 = phi i32 [ %inc.lcssa3, %for.cond1.preheader ], [ %inc, %for.body3 ]
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%0 = phi i32 [ undef, %for.cond1.preheader ], [ %inc54, %for.body3 ]
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%idxprom = sext i32 %0 to i64
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%arrayidx = getelementptr inbounds [1 x i32], [1 x i32]* @b, i64 0, i64 %idxprom
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store i32 4, i32* %arrayidx, align 4
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%inc = add nsw i32 %inc1, 1
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%tobool2 = icmp eq i32 %inc, 0
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br i1 %tobool2, label %for.cond1.for.inc4_crit_edge, label %for.body3
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for.cond1.for.inc4_crit_edge: ; preds = %for.body3
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%inc.lcssa = phi i32 [ %inc, %for.body3 ]
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%.lcssa = phi i32 [ %inc54, %for.body3 ]
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%inc5 = add nsw i32 %.lcssa, 1
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br label %for.cond1.preheader
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}
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