llvm/test/Transforms/LoopUnroll/runtime-loop4.ll
Sanjoy Das 888e8e3a66 [LoopUnrollRuntime] Avoid high-cost trip count computation.
Summary:
Runtime unrolling of loops needs to emit an expression to compute the
loop's runtime trip-count.  Avoid runtime unrolling if this computation
will be expensive.

Depends on D8993.

Reviewers: atrick

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8994

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234846 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-14 03:20:38 +00:00

45 lines
1.0 KiB
LLVM

; RUN: opt < %s -S -O2 -unroll-runtime=true | FileCheck %s
; Check runtime unrolling prologue can be promoted by LICM pass.
; CHECK: entry:
; CHECK: %xtraiter
; CHECK: %lcmp.mod
; CHECK: loop1:
; CHECK: br i1 %lcmp.mod
; CHECK: loop2.prol:
define void @unroll(i32 %iter, i32* %addr1, i32* %addr2) nounwind {
entry:
br label %loop1
loop1:
%iv1 = phi i32 [ 0, %entry ], [ %inc1, %loop1.latch ]
%offset1 = getelementptr i32, i32* %addr1, i32 %iv1
store i32 %iv1, i32* %offset1, align 4
br label %loop2.header
loop2.header:
%e = icmp uge i32 %iter, 1
br i1 %e, label %loop2, label %exit2
loop2:
%iv2 = phi i32 [ 0, %loop2.header ], [ %inc2, %loop2 ]
%offset2 = getelementptr i32, i32* %addr2, i32 %iv2
store i32 %iv2, i32* %offset2, align 4
%inc2 = add i32 %iv2, 1
%exitcnd2 = icmp uge i32 %inc2, %iter
br i1 %exitcnd2, label %exit2, label %loop2
exit2:
br label %loop1.latch
loop1.latch:
%inc1 = add i32 %iv1, 1
%exitcnd1 = icmp uge i32 %inc1, 1024
br i1 %exitcnd1, label %exit, label %loop1
exit:
ret void
}