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llvm-mirror/test/Transforms/LoopStrengthReduce/two-combinations-bug.ll
David Green fe632bfdc8 [LSR] Limit the recursion for setup cost
In some circumstances we can end up with setup costs that are very complex to
compute, even though the scevs are not very complex to create. This can also
lead to setupcosts that are calculated to be exactly -1, which LSR treats as an
invalid cost. This patch puts a limit on the recursion depth for setup cost to
prevent them taking too long.

Thanks to @reames for the report and test case.

Differential Revision: https://reviews.llvm.org/D60944

llvm-svn: 358958
2019-04-23 08:52:21 +00:00

56 lines
2.9 KiB
LLVM

; RUN: opt < %s -loop-reduce -lsr-setupcost-depth-limit=1 -S | FileCheck %s
; This test is adapted from the n-body test of the LLVM test-suite: A bug in
; r345114 caused LSR to generate incorrect code. The test verifies that the
; induction variable generated for the inner loop depends on the induction
; variable of the outer loop.
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
%struct.planet.0.3.6.11.12.15.16.17.24.25.26.33.44 = type { double, double, double, double, double, double, double }
; Function Attrs: nounwind uwtable
define dso_local void @advance(i32 %nbodies, %struct.planet.0.3.6.11.12.15.16.17.24.25.26.33.44* nocapture %bodies) local_unnamed_addr #0 {
; CHECK-LABEL: @advance(
; CHECK: for.cond.loopexit:
; CHECK: [[LSR_IV_NEXT:%.*]] = add i64 [[LSR_IV:%.*]], -1
; CHECK: br label %for.body
; CHECK: for.body:
; CHECK: [[LSR_IV]] = phi i64 [ [[LSR_IV_NEXT]]
; CHECK: br label %for.body3
; CHECK: for.body3:
; CHECK: [[LSR_IV1:%.*]] = phi i64 [ [[LSR_IV_NEXT2:%.*]], %for.body3 ], [ [[LSR_IV]], %for.body ]
; CHECK: [[LSR_IV_NEXT2]] = add i64 [[LSR_IV1]], -1
; CHECK: [[EXITCOND:%.*]] = icmp eq i64 [[LSR_IV_NEXT2]], 0
; CHECK: br i1 [[EXITCOND]], label %for.cond.loopexit, label %for.body3
;
entry:
%wide.trip.count = zext i32 %nbodies to i64
br label %for.body
for.cond.loopexit: ; preds = %for.body3
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
br label %for.body
for.body: ; preds = %for.cond.loopexit, %entry
%indvars.iv = phi i64 [ 1, %entry ], [ %indvars.iv.next, %for.cond.loopexit ]
br label %for.body3
for.body3: ; preds = %for.body3, %for.body
%indvars.iv98 = phi i64 [ %indvars.iv, %for.body ], [ %indvars.iv.next99, %for.body3 ]
%z9 = getelementptr inbounds %struct.planet.0.3.6.11.12.15.16.17.24.25.26.33.44, %struct.planet.0.3.6.11.12.15.16.17.24.25.26.33.44* %bodies, i64 %indvars.iv98, i32 2
%tmp = load double, double* %z9, align 8, !tbaa !0
%indvars.iv.next99 = add nuw nsw i64 %indvars.iv98, 1
%exitcond = icmp eq i64 %indvars.iv.next99, %wide.trip.count
br i1 %exitcond, label %for.cond.loopexit, label %for.body3
}
attributes #0 = { nounwind uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
!0 = !{!1, !2, i64 16}
!1 = !{!"planet", !2, i64 0, !2, i64 8, !2, i64 16, !2, i64 24, !2, i64 32, !2, i64 40, !2, i64 48}
!2 = !{!"double", !3, i64 0}
!3 = !{!"omnipotent char", !4, i64 0}
!4 = !{!"Simple C/C++ TBAA"}