llvm-mirror/test/Transforms/LoopVectorize/if-conversion-nest.ll
Roman Lebedev 2926999f1a [InstCombine] Revert rL341831: relax one-use check in foldICmpAddConstant() (PR44100)
rL341831 moved one-use check higher up, restricting a few folds
that produced a single instruction from two instructions to the case
where the inner instruction would go away.

Original commit message:
> InstCombine: move hasOneUse check to the top of foldICmpAddConstant
>
> There were two combines not covered by the check before now,
> neither of which actually differed from normal in the benefit analysis.
>
> The most recent seems to be because it was just added at the top of the
> function (naturally). The older is from way back in 2008 (r46687)
> when we just didn't put those checks in so routinely, and has been
> diligently maintained since.

From the commit message alone, there doesn't seem to be a
deeper motivation, deeper problem that was trying to solve,
other than 'fixing the wrong one-use check'.

As i have briefly discusses in IRC with Tim, the original motivation
can no longer be recovered, too much time has passed.

However i believe that the original fold was doing the right thing,
we should be performing such a transformation even if the inner `add`
will not go away - that will still unchain the comparison from `add`,
it will no longer need to wait for `add` to compute.

Doing so doesn't seem to break any particular idioms,
as least as far as i can see.

References https://bugs.llvm.org/show_bug.cgi?id=44100
2019-12-02 18:06:15 +03:00

119 lines
6.6 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -enable-if-conversion -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"
define i32 @foo(i32* nocapture %A, i32* nocapture %B, i32 %n) {
; CHECK-LABEL: @foo(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[CMP26:%.*]] = icmp sgt i32 [[N:%.*]], 0
; CHECK-NEXT: br i1 [[CMP26]], label [[FOR_BODY_PREHEADER:%.*]], label [[FOR_END:%.*]]
; CHECK: for.body.preheader:
; CHECK-NEXT: [[TMP0:%.*]] = add i32 [[N]], -1
; CHECK-NEXT: [[TMP1:%.*]] = zext i32 [[TMP0]] to i64
; CHECK-NEXT: [[TMP2:%.*]] = add nuw nsw i64 [[TMP1]], 1
; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i32 [[TMP0]], 3
; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_MEMCHECK:%.*]]
; CHECK: vector.memcheck:
; CHECK-NEXT: [[TMP3:%.*]] = add i32 [[N]], -1
; CHECK-NEXT: [[TMP4:%.*]] = zext i32 [[TMP3]] to i64
; CHECK-NEXT: [[TMP5:%.*]] = add nuw nsw i64 [[TMP4]], 1
; CHECK-NEXT: [[SCEVGEP:%.*]] = getelementptr i32, i32* [[A:%.*]], i64 [[TMP5]]
; CHECK-NEXT: [[SCEVGEP4:%.*]] = getelementptr i32, i32* [[B:%.*]], i64 [[TMP5]]
; CHECK-NEXT: [[BOUND0:%.*]] = icmp ugt i32* [[SCEVGEP4]], [[A]]
; CHECK-NEXT: [[BOUND1:%.*]] = icmp ugt i32* [[SCEVGEP]], [[B]]
; CHECK-NEXT: [[FOUND_CONFLICT:%.*]] = and i1 [[BOUND0]], [[BOUND1]]
; CHECK-NEXT: br i1 [[FOUND_CONFLICT]], label [[SCALAR_PH]], label [[VECTOR_PH:%.*]]
; CHECK: vector.ph:
; CHECK-NEXT: [[N_VEC:%.*]] = and i64 [[TMP2]], 8589934588
; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
; CHECK: vector.body:
; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, i32* [[A]], i64 [[INDEX]]
; CHECK-NEXT: [[TMP7:%.*]] = bitcast i32* [[TMP6]] to <4 x i32>*
; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <4 x i32>, <4 x i32>* [[TMP7]], align 4, !alias.scope !0, !noalias !3
; CHECK-NEXT: [[TMP8:%.*]] = getelementptr inbounds i32, i32* [[B]], i64 [[INDEX]]
; CHECK-NEXT: [[TMP9:%.*]] = bitcast i32* [[TMP8]] to <4 x i32>*
; CHECK-NEXT: [[WIDE_LOAD6:%.*]] = load <4 x i32>, <4 x i32>* [[TMP9]], align 4, !alias.scope !3
; CHECK-NEXT: [[TMP10:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], [[WIDE_LOAD6]]
; CHECK-NEXT: [[TMP11:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], <i32 19, i32 19, i32 19, i32 19>
; CHECK-NEXT: [[TMP12:%.*]] = icmp slt <4 x i32> [[WIDE_LOAD6]], <i32 4, i32 4, i32 4, i32 4>
; CHECK-NEXT: [[TMP13:%.*]] = select <4 x i1> [[TMP12]], <4 x i32> <i32 4, i32 4, i32 4, i32 4>, <4 x i32> <i32 5, i32 5, i32 5, i32 5>
; CHECK-NEXT: [[TMP14:%.*]] = and <4 x i1> [[TMP11]], [[TMP10]]
; CHECK-NEXT: [[TMP15:%.*]] = xor <4 x i1> [[TMP11]], <i1 true, i1 true, i1 true, i1 true>
; CHECK-NEXT: [[TMP16:%.*]] = and <4 x i1> [[TMP10]], [[TMP15]]
; CHECK-NEXT: [[PREDPHI:%.*]] = select <4 x i1> [[TMP14]], <4 x i32> <i32 3, i32 3, i32 3, i32 3>, <4 x i32> <i32 9, i32 9, i32 9, i32 9>
; CHECK-NEXT: [[PREDPHI7:%.*]] = select <4 x i1> [[TMP16]], <4 x i32> [[TMP13]], <4 x i32> [[PREDPHI]]
; CHECK-NEXT: [[TMP17:%.*]] = bitcast i32* [[TMP6]] to <4 x i32>*
; CHECK-NEXT: store <4 x i32> [[PREDPHI7]], <4 x i32>* [[TMP17]], align 4, !alias.scope !0, !noalias !3
; CHECK-NEXT: [[INDEX_NEXT]] = add i64 [[INDEX]], 4
; CHECK-NEXT: [[TMP18:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
; CHECK-NEXT: br i1 [[TMP18]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop !5
; CHECK: middle.block:
; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[TMP2]], [[N_VEC]]
; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_END_LOOPEXIT:%.*]], label [[SCALAR_PH]]
; CHECK: scalar.ph:
; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[FOR_BODY_PREHEADER]] ], [ 0, [[VECTOR_MEMCHECK]] ]
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[IF_END14:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i32, i32* [[A]], i64 [[INDVARS_IV]]
; CHECK-NEXT: [[TMP19:%.*]] = load i32, i32* [[ARRAYIDX]], align 4
; CHECK-NEXT: [[ARRAYIDX2:%.*]] = getelementptr inbounds i32, i32* [[B]], i64 [[INDVARS_IV]]
; CHECK-NEXT: [[TMP20:%.*]] = load i32, i32* [[ARRAYIDX2]], align 4
; CHECK-NEXT: [[CMP3:%.*]] = icmp sgt i32 [[TMP19]], [[TMP20]]
; CHECK-NEXT: br i1 [[CMP3]], label [[IF_THEN:%.*]], label [[IF_END14]]
; CHECK: if.then:
; CHECK-NEXT: [[CMP6:%.*]] = icmp sgt i32 [[TMP19]], 19
; CHECK-NEXT: br i1 [[CMP6]], label [[IF_END14]], label [[IF_ELSE:%.*]]
; CHECK: if.else:
; CHECK-NEXT: [[CMP10:%.*]] = icmp slt i32 [[TMP20]], 4
; CHECK-NEXT: [[DOT:%.*]] = select i1 [[CMP10]], i32 4, i32 5
; CHECK-NEXT: br label [[IF_END14]]
; CHECK: if.end14:
; CHECK-NEXT: [[X_0:%.*]] = phi i32 [ 9, [[FOR_BODY]] ], [ 3, [[IF_THEN]] ], [ [[DOT]], [[IF_ELSE]] ]
; CHECK-NEXT: store i32 [[X_0]], i32* [[ARRAYIDX]], align 4
; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1
; CHECK-NEXT: [[LFTR_WIDEIV:%.*]] = trunc i64 [[INDVARS_IV_NEXT]] to i32
; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i32 [[LFTR_WIDEIV]], [[N]]
; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR_END_LOOPEXIT]], label [[FOR_BODY]], !llvm.loop !7
; CHECK: for.end.loopexit:
; CHECK-NEXT: br label [[FOR_END]]
; CHECK: for.end:
; CHECK-NEXT: ret i32 undef
;
entry:
%cmp26 = icmp sgt i32 %n, 0
br i1 %cmp26, label %for.body, label %for.end
for.body:
%indvars.iv = phi i64 [ %indvars.iv.next, %if.end14 ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32, i32* %A, i64 %indvars.iv
%0 = load i32, i32* %arrayidx, align 4
%arrayidx2 = getelementptr inbounds i32, i32* %B, i64 %indvars.iv
%1 = load i32, i32* %arrayidx2, align 4
%cmp3 = icmp sgt i32 %0, %1
br i1 %cmp3, label %if.then, label %if.end14
if.then:
%cmp6 = icmp sgt i32 %0, 19
br i1 %cmp6, label %if.end14, label %if.else
if.else:
%cmp10 = icmp slt i32 %1, 4
%. = select i1 %cmp10, i32 4, i32 5
br label %if.end14
if.end14:
%x.0 = phi i32 [ 9, %for.body ], [ 3, %if.then ], [ %., %if.else ] ; <------------- A PHI with 3 entries that we can still vectorize.
store i32 %x.0, i32* %arrayidx, 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, %n
br i1 %exitcond, label %for.end, label %for.body
for.end:
ret i32 undef
}