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