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e62289b98f
When ExactBECount is a constant, use it for MaxBECount. When MaxBECount cannot be computed, replace it with ExactBECount. Fixes PR9424. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127342 91177308-0d34-0410-b5e6-96231b3b80d8
35 lines
1.2 KiB
LLVM
35 lines
1.2 KiB
LLVM
; RUN: opt -indvars %s
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; PR9424: Attempt to use a SCEVCouldNotCompute object!
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; The inner loop computes the Step and Start of the outer loop.
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; Call that Vexit. The outer End value is max(2,Vexit), because
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; the condition "icmp %4 < 2" does not guard the outer loop.
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; SCEV knows that Vexit has range [2,4], so End == Vexit == Start.
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; Now we have ExactBECount == 0. However, MinStart == 2 and MaxEnd == 4.
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; Since the stride is variable and may wrap, we cannot compute
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; MaxBECount. SCEV should override MaxBECount with ExactBECount.
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define void @bar() nounwind {
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entry:
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%. = select i1 undef, i32 2, i32 1
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br label %"5.preheader"
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"4": ; preds = %"5.preheader", %"4"
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%0 = phi i32 [ 0, %"5.preheader" ], [ %1, %"4" ]
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%1 = add nsw i32 %0, 1
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%2 = icmp sgt i32 %., %1
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br i1 %2, label %"4", label %"9"
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"9": ; preds = %"4"
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%3 = add i32 %6, 1
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%4 = add i32 %3, %1
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%5 = icmp slt i32 %4, 2
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br i1 %5, label %"5.preheader", label %return
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"5.preheader": ; preds = %"9", %entry
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%6 = phi i32 [ 0, %entry ], [ %4, %"9" ]
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br label %"4"
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return: ; preds = %"9"
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ret void
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}
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