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Michael Kuperstein 2c0f3dbd6f [LV] Don't vectorize when we have a small static bound on trip count
We currently check if the exact trip count is known and is smaller than the
"tiny loop" bound. We should be checking the maximum bound on the trip count
instead.

Differential Revision: https://reviews.llvm.org/D27690

llvm-svn: 289583
2016-12-13 20:38:18 +00:00

58 lines
2.3 KiB
LLVM

; RUN: opt < %s -loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -dce -instcombine -S | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
@a = common global [2048 x i32] zeroinitializer, align 16
@b = common global [2048 x i32] zeroinitializer, align 16
@c = common global [2048 x i32] zeroinitializer, align 16
;CHECK-LABEL: @example1(
;CHECK-NOT: load <4 x i32>
;CHECK: ret void
define void @example1() nounwind uwtable ssp {
br label %1
; <label>:1 ; preds = %1, %0
%indvars.iv = phi i64 [ 0, %0 ], [ %indvars.iv.next, %1 ]
%2 = getelementptr inbounds [2048 x i32], [2048 x i32]* @b, i64 0, i64 %indvars.iv
%3 = load i32, i32* %2, align 4
%4 = getelementptr inbounds [2048 x i32], [2048 x i32]* @c, i64 0, i64 %indvars.iv
%5 = load i32, i32* %4, align 4
%6 = add nsw i32 %5, %3
%7 = getelementptr inbounds [2048 x i32], [2048 x i32]* @a, i64 0, i64 %indvars.iv
store i32 %6, i32* %7, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, 8 ; <----- A really small trip count.
br i1 %exitcond, label %8, label %1
; <label>:8 ; preds = %1
ret void
}
;CHECK-LABEL: @bound1(
;CHECK-NOT: load <4 x i32>
;CHECK: ret void
define void @bound1(i32 %k) nounwind uwtable ssp {
br label %1
; <label>:1 ; preds = %1, %0
%indvars.iv = phi i64 [ 0, %0 ], [ %indvars.iv.next, %1 ]
%2 = getelementptr inbounds [2048 x i32], [2048 x i32]* @b, i64 0, i64 %indvars.iv
%3 = load i32, i32* %2, align 4
%4 = getelementptr inbounds [2048 x i32], [2048 x i32]* @c, i64 0, i64 %indvars.iv
%5 = load i32, i32* %4, align 4
%6 = add nsw i32 %5, %3
%7 = getelementptr inbounds [2048 x i32], [2048 x i32]* @a, i64 0, i64 %indvars.iv
store i32 %6, i32* %7, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%large = icmp sge i32 %lftr.wideiv, 8
%exitcond = icmp eq i32 %lftr.wideiv, %k
%realexit = or i1 %large, %exitcond
br i1 %realexit, label %8, label %1
; <label>:8 ; preds = %1
ret void
}