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llvm-mirror/test/Transforms/LoopInterchange/not-interchanged-tightly-nested.ll
Congzhe Cao 8164f4eeb7 [LoopInterchange] fix tightlyNested() in LoopInterchange legality
This is yet another attempt to fix tightlyNested().

Add checks in tightlyNested() for the inner loop exit block,
such that 1) if there is control-flow divergence in between the inner
loop exit block and the outer loop latch, or 2) if the inner loop exit
block contains unsafe instructions, tightlyNested() returns false.

The reasoning behind is that after interchange, the original inner loop
exit block, which was part of the outer loop, would be put into the new
inner loop, and will be executed different number of times before and
after interchange. Thus it should be dealt with appropriately.

Reviewed By: Whitney

Differential Revision: https://reviews.llvm.org/D98263
2021-03-24 15:49:25 -04:00

144 lines
4.3 KiB
LLVM

; REQUIRES: asserts
; RUN: opt < %s -basic-aa -loop-interchange -verify-dom-info -verify-loop-info \
; RUN: -S -debug 2>&1 | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@A = common global [100 x [100 x i32]] zeroinitializer
@B = common global [100 x i32] zeroinitializer
@C = common global [100 x [100 x i32]] zeroinitializer
@D = common global [100 x [100 x [100 x i32]]] zeroinitializer
;; Loops not tightly nested are not interchanged
;; for(int j=0;j<N;j++) {
;; B[j] = j+k;
;; for(int i=0;i<N;i++)
;; A[j][i] = A[j][i]+B[j];
;; }
; CHECK: Not interchanging loops. Cannot prove legality.
define void @interchange_05(i32 %k, i32 %N){
entry:
%cmp30 = icmp sgt i32 %N, 0
br i1 %cmp30, label %for.body.lr.ph, label %for.end17
for.body.lr.ph:
%0 = add i32 %N, -1
%1 = zext i32 %k to i64
br label %for.body
for.body:
%indvars.iv32 = phi i64 [ 0, %for.body.lr.ph ], [ %indvars.iv.next33, %for.inc15 ]
%2 = add nsw i64 %indvars.iv32, %1
%arrayidx = getelementptr inbounds [100 x i32], [100 x i32]* @B, i64 0, i64 %indvars.iv32
%3 = trunc i64 %2 to i32
store i32 %3, i32* %arrayidx
br label %for.body3
for.body3:
%indvars.iv = phi i64 [ 0, %for.body ], [ %indvars.iv.next, %for.body3 ]
%arrayidx7 = getelementptr inbounds [100 x [100 x i32]], [100 x [100 x i32]]* @A, i64 0, i64 %indvars.iv32, i64 %indvars.iv
%4 = load i32, i32* %arrayidx7
%add10 = add nsw i32 %3, %4
store i32 %add10, i32* %arrayidx7
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv to i32
%exitcond = icmp eq i32 %lftr.wideiv, %0
br i1 %exitcond, label %for.inc15, label %for.body3
for.inc15:
%indvars.iv.next33 = add nuw nsw i64 %indvars.iv32, 1
%lftr.wideiv35 = trunc i64 %indvars.iv32 to i32
%exitcond36 = icmp eq i32 %lftr.wideiv35, %0
br i1 %exitcond36, label %for.end17, label %for.body
for.end17:
ret void
}
declare void @foo(...) readnone
;; Loops not tightly nested are not interchanged
;; for(int j=0;j<N;j++) {
;; foo();
;; for(int i=2;i<N;i++)
;; A[j][i] = A[j][i]+k;
;; }
; CHECK: Not interchanging loops. Cannot prove legality.
define void @interchange_06(i32 %k, i32 %N) {
entry:
%cmp22 = icmp sgt i32 %N, 0
br i1 %cmp22, label %for.body.lr.ph, label %for.end12
for.body.lr.ph:
%0 = add i32 %N, -1
br label %for.body
for.body:
%indvars.iv24 = phi i64 [ 0, %for.body.lr.ph ], [ %indvars.iv.next25, %for.inc10 ]
tail call void (...) @foo()
br label %for.body3
for.body3:
%indvars.iv = phi i64 [ %indvars.iv.next, %for.body3 ], [ 2, %for.body ]
%arrayidx5 = getelementptr inbounds [100 x [100 x i32]], [100 x [100 x i32]]* @A, i64 0, i64 %indvars.iv24, i64 %indvars.iv
%1 = load i32, i32* %arrayidx5
%add = add nsw i32 %1, %k
store i32 %add, i32* %arrayidx5
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv to i32
%exitcond = icmp eq i32 %lftr.wideiv, %0
br i1 %exitcond, label %for.inc10, label %for.body3
for.inc10:
%indvars.iv.next25 = add nuw nsw i64 %indvars.iv24, 1
%lftr.wideiv26 = trunc i64 %indvars.iv24 to i32
%exitcond27 = icmp eq i32 %lftr.wideiv26, %0
br i1 %exitcond27, label %for.end12, label %for.body
for.end12:
ret void
}
;; The following Loop is not considered tightly nested and is not interchanged.
;; The outer loop header does not branch to the inner loop preheader, or the
;; inner loop header, or the outer loop latch.
; CHECK: Not interchanging loops. Cannot prove legality.
define void @interchange_07(i32 %k, i32 %N, i32 %ny) {
entry:
br label %for1.header
for1.header:
%j23 = phi i32 [ 0, %entry ], [ %j.next24, %for1.inc10 ]
%cmp21 = icmp slt i32 0, %ny
br label %singleSucc
singleSucc:
br i1 %cmp21, label %preheader.j, label %for1.inc10
preheader.j:
br label %for2
for2:
%j = phi i32 [ %j.next, %for2 ], [ 0, %preheader.j ]
%arrayidx5 = getelementptr inbounds [100 x [100 x i32]], [100 x [100 x i32]]* @A, i32 0, i32 %j, i32 %j23
%lv = load i32, i32* %arrayidx5
%add = add nsw i32 %lv, %k
store i32 %add, i32* %arrayidx5
%j.next = add nuw nsw i32 %j, 1
%exitcond = icmp eq i32 %j, 99
br i1 %exitcond, label %for1.inc10, label %for2
for1.inc10:
%j.next24 = add nuw nsw i32 %j23, 1
%exitcond26 = icmp eq i32 %j23, 99
br i1 %exitcond26, label %for.end12, label %for1.header
for.end12:
ret void
}