50 lines
1.8 KiB
LLVM
50 lines
1.8 KiB
LLVM
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; RUN: opt < %s -S -unroll-runtime -unroll-count=2 -loop-unroll -unroll-runtime-epilog=true | FileCheck %s -check-prefix=EPILOG
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; RUN: opt < %s -S -unroll-runtime -unroll-count=2 -loop-unroll -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
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target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
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; This test case documents how runtime loop unrolling handles the case
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; when the backedge-count is -1.
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; If %N, the backedge-taken count, is -1 then %0 unsigned-overflows
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; and is 0. %xtraiter too is 0, signifying that the total trip-count
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; is divisible by 2. The prologue then branches to the unrolled loop
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; and executes the 2^32 iterations there, in groups of 2.
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; EPILOG: entry:
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; EPILOG-NEXT: %0 = add i32 %N, 1
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; EPILOG-NEXT: %xtraiter = and i32 %0, 1
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; EPILOG-NEXT: %1 = icmp ult i32 %N, 1
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; EPILOG-NEXT: br i1 %1, label %while.end.unr-lcssa, label %entry.new
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; EPILOG: while.body:
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; EPILOG: %lcmp.mod = icmp ne i32 %xtraiter, 0
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; EPILOG-NEXT: br i1 %lcmp.mod, label %while.body.epil.preheader, label %while.end
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; EPILOG: while.body.epil:
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; PROLOG: entry:
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; PROLOG-NEXT: %0 = add i32 %N, 1
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; PROLOG-NEXT: %xtraiter = and i32 %0, 1
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; PROLOG-NEXT: %lcmp.mod = icmp ne i32 %xtraiter, 0
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; PROLOG-NEXT: br i1 %lcmp.mod, label %while.body.prol.preheader, label %while.body.prol.loopexit
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; PROLOG: while.body.prol:
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; PROLOG: %1 = icmp ult i32 %N, 1
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; PROLOG-NEXT: br i1 %1, label %while.end, label %entry.new
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; PROLOG: while.body:
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; Function Attrs: nounwind readnone ssp uwtable
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define i32 @foo(i32 %N) {
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entry:
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br label %while.body
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while.body: ; preds = %while.body, %entry
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%i = phi i32 [ 0, %entry ], [ %inc, %while.body ]
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%cmp = icmp eq i32 %i, %N
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%inc = add i32 %i, 1
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br i1 %cmp, label %while.end, label %while.body
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while.end: ; preds = %while.body
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ret i32 %i
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}
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