23ce61b663
Summary: It is incorrect to compare TripCount (which is BECount + 1) with extraiters (or Count) to check if we should enter unrolled loop or not, because TripCount can potentially overflow (when BECount is max unsigned integer). While comparing BECount with (Count - 1) is overflow safe and therefore correct. Reviewer: hfinkel Differential Revision: http://reviews.llvm.org/D19256 From: Evgeny Stupachenko <evstupac@gmail.com> llvm-svn: 267662
40 lines
1.5 KiB
LLVM
40 lines
1.5 KiB
LLVM
; RUN: opt < %s -S -loop-unroll -mtriple aarch64 -mcpu=cortex-a57 | FileCheck %s -check-prefix=EPILOG
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; RUN: opt < %s -S -loop-unroll -mtriple aarch64 -mcpu=cortex-a57 -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
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; Tests for unrolling loops with run-time trip counts
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; EPILOG: %xtraiter = and i32 %n
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; EPILOG: for.body:
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; EPILOG: %lcmp.mod = icmp ne i32 %xtraiter, 0
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; EPILOG: br i1 %lcmp.mod, label %for.body.epil.preheader, label %for.end.loopexit
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; EPILOG: for.body.epil:
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; PROLOG: %xtraiter = and i32 %n
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; PROLOG: %lcmp.mod = icmp ne i32 %xtraiter, 0
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; PROLOG: br i1 %lcmp.mod, label %for.body.prol.preheader, label %for.body.prol.loopexit
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; PROLOG: for.body.prol:
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; PROLOG: for.body:
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define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly {
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entry:
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%cmp1 = icmp eq i32 %n, 0
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br i1 %cmp1, label %for.end, label %for.body
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for.body: ; preds = %for.body, %entry
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
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%sum.02 = phi i32 [ %add, %for.body ], [ 0, %entry ]
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%arrayidx = getelementptr inbounds i32, i32* %a, i64 %indvars.iv
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%0 = load i32, i32* %arrayidx, align 4
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%add = add nsw i32 %0, %sum.02
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%indvars.iv.next = add i64 %indvars.iv, 1
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%lftr.wideiv = trunc i64 %indvars.iv.next to i32
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%exitcond = icmp eq i32 %lftr.wideiv, %n
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br i1 %exitcond, label %for.end, label %for.body
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for.end: ; preds = %for.body, %entry
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%sum.0.lcssa = phi i32 [ 0, %entry ], [ %add, %for.body ]
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ret i32 %sum.0.lcssa
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}
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