llvm-mirror/test/Transforms/LoopVectorize/miniters.ll
Wei Mi f8e0f7a698 The patch replace the overflow check in loop vectorization with the minimum loop iterations check.
The loop minimum iterations check below ensures the loop has enough trip count so the generated
vector loop will likely be executed, and it covers the overflow check.

Differential Revision: http://reviews.llvm.org/D12107.

llvm-svn: 245952
2015-08-25 16:43:47 +00:00

46 lines
2.0 KiB
LLVM

; RUN: opt %s -loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S | FileCheck %s
; RUN: opt %s -loop-vectorize -force-vector-interleave=2 -force-vector-width=4 -S | FileCheck %s -check-prefix=UNROLL
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@b = common global [1000 x i32] zeroinitializer, align 16
@c = common global [1000 x i32] zeroinitializer, align 16
@a = common global [1000 x i32] zeroinitializer, align 16
; Generate min.iters.check to skip the vector loop and jump to scalar.ph directly when loop iteration number is less than VF * UF.
; CHECK-LABEL: foo(
; CHECK: %min.iters.check = icmp ult i64 %N, 4
; CHECK: br i1 %min.iters.check, label %scalar.ph, label %min.iters.checked
; UNROLL-LABEL: foo(
; UNROLL: %min.iters.check = icmp ult i64 %N, 8
; UNROLL: br i1 %min.iters.check, label %scalar.ph, label %min.iters.checked
define void @foo(i64 %N) {
entry:
%cmp.8 = icmp sgt i64 %N, 0
br i1 %cmp.8, label %for.body.preheader, label %for.end
for.body.preheader: ; preds = %entry
br label %for.body
for.body: ; preds = %for.body, %for.body.preheader
%i.09 = phi i64 [ %inc, %for.body ], [ 0, %for.body.preheader ]
%arrayidx = getelementptr inbounds [1000 x i32], [1000 x i32]* @b, i64 0, i64 %i.09
%tmp = load i32, i32* %arrayidx, align 4
%arrayidx1 = getelementptr inbounds [1000 x i32], [1000 x i32]* @c, i64 0, i64 %i.09
%tmp1 = load i32, i32* %arrayidx1, align 4
%add = add nsw i32 %tmp1, %tmp
%arrayidx2 = getelementptr inbounds [1000 x i32], [1000 x i32]* @a, i64 0, i64 %i.09
store i32 %add, i32* %arrayidx2, align 4
%inc = add nuw nsw i64 %i.09, 1
%exitcond = icmp eq i64 %inc, %N
br i1 %exitcond, label %for.end.loopexit, label %for.body
for.end.loopexit: ; preds = %for.body
br label %for.end
for.end: ; preds = %for.end.loopexit, %entry
ret void
}