Add support to interchange loops with reductions.
This patch enables interchanging of tightly nested loops with reductions.
Differential Revision: http://reviews.llvm.org/D8314
llvm-svn: 235571
diff --git a/llvm/test/Transforms/LoopInterchange/reductions.ll b/llvm/test/Transforms/LoopInterchange/reductions.ll
new file mode 100644
index 0000000..86a44da
--- /dev/null
+++ b/llvm/test/Transforms/LoopInterchange/reductions.ll
@@ -0,0 +1,235 @@
+; RUN: opt < %s -basicaa -loop-interchange -S | FileCheck %s
+
+@A = common global [500 x [500 x i32]] zeroinitializer
+@X = common global i32 0
+@B = common global [500 x [500 x i32]] zeroinitializer
+@Y = common global i32 0
+
+;; for( int i=1;i<N;i++)
+;; for( int j=1;j<N;j++)
+;; X+=A[j][i];
+
+define void @reduction_01(i32 %N) {
+entry:
+ %cmp16 = icmp sgt i32 %N, 1
+ br i1 %cmp16, label %for.body3.lr.ph, label %for.end8
+
+for.body3.lr.ph: ; preds = %entry, %for.cond1.for.inc6_crit_edge
+ %indvars.iv18 = phi i64 [ %indvars.iv.next19, %for.cond1.for.inc6_crit_edge ], [ 1, %entry ]
+ %X.promoted = load i32, i32* @X
+ br label %for.body3
+
+for.body3: ; preds = %for.body3, %for.body3.lr.ph
+ %indvars.iv = phi i64 [ 1, %for.body3.lr.ph ], [ %indvars.iv.next, %for.body3 ]
+ %add15 = phi i32 [ %X.promoted, %for.body3.lr.ph ], [ %add, %for.body3 ]
+ %arrayidx5 = getelementptr inbounds [500 x [500 x i32]], [500 x [500 x i32]]* @A, i64 0, i64 %indvars.iv, i64 %indvars.iv18
+ %0 = load i32, i32* %arrayidx5
+ %add = add nsw i32 %add15, %0
+ %indvars.iv.next = add nuw nsw 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.cond1.for.inc6_crit_edge, label %for.body3
+
+for.cond1.for.inc6_crit_edge: ; preds = %for.body3
+ store i32 %add, i32* @X
+ %indvars.iv.next19 = add nuw nsw i64 %indvars.iv18, 1
+ %lftr.wideiv20 = trunc i64 %indvars.iv.next19 to i32
+ %exitcond21 = icmp eq i32 %lftr.wideiv20, %N
+ br i1 %exitcond21, label %for.end8, label %for.body3.lr.ph
+
+for.end8: ; preds = %for.cond1.for.inc6_crit_edge, %entry
+ ret void
+}
+
+;; Loop is interchanged check that the phi nodes are split and the promoted value is used instead of the reduction phi.
+; CHECK-LABEL: @reduction_01
+; CHECK: for.body3: ; preds = %for.body3.preheader, %for.body3.split
+; CHECK: %indvars.iv = phi i64 [ %indvars.iv.next, %for.body3.split ], [ 1, %for.body3.preheader ]
+; CHECK: br label %for.body3.lr.ph.preheader
+; CHECK: %add = add nsw i32 %X.promoted
+
+
+;; Test for more than 1 reductions inside a loop.
+;; for( int i=1;i<N;i++)
+;; for( int j=1;j<N;j++)
+;; for( int k=1;k<N;k++) {
+;; X+=A[k][j];
+;; Y+=B[k][i];
+;; }
+
+define void @reduction_02(i32 %N) {
+entry:
+ %cmp34 = icmp sgt i32 %N, 1
+ br i1 %cmp34, label %for.cond4.preheader.preheader, label %for.end19
+
+for.cond4.preheader.preheader: ; preds = %entry, %for.inc17
+ %indvars.iv40 = phi i64 [ %indvars.iv.next41, %for.inc17 ], [ 1, %entry ]
+ br label %for.body6.lr.ph
+
+for.body6.lr.ph: ; preds = %for.cond4.for.inc14_crit_edge, %for.cond4.preheader.preheader
+ %indvars.iv36 = phi i64 [ %indvars.iv.next37, %for.cond4.for.inc14_crit_edge ], [ 1, %for.cond4.preheader.preheader ]
+ %X.promoted = load i32, i32* @X
+ %Y.promoted = load i32, i32* @Y
+ br label %for.body6
+
+for.body6: ; preds = %for.body6, %for.body6.lr.ph
+ %indvars.iv = phi i64 [ 1, %for.body6.lr.ph ], [ %indvars.iv.next, %for.body6 ]
+ %add1331 = phi i32 [ %Y.promoted, %for.body6.lr.ph ], [ %add13, %for.body6 ]
+ %add30 = phi i32 [ %X.promoted, %for.body6.lr.ph ], [ %add, %for.body6 ]
+ %arrayidx8 = getelementptr inbounds [500 x [500 x i32]], [500 x [500 x i32]]* @A, i64 0, i64 %indvars.iv, i64 %indvars.iv36
+ %0 = load i32, i32* %arrayidx8
+ %add = add nsw i32 %add30, %0
+ %arrayidx12 = getelementptr inbounds [500 x [500 x i32]], [500 x [500 x i32]]* @B, i64 0, i64 %indvars.iv, i64 %indvars.iv40
+ %1 = load i32, i32* %arrayidx12
+ %add13 = add nsw i32 %add1331, %1
+ %indvars.iv.next = add nuw nsw 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.cond4.for.inc14_crit_edge, label %for.body6
+
+for.cond4.for.inc14_crit_edge: ; preds = %for.body6
+ store i32 %add, i32* @X
+ store i32 %add13, i32* @Y
+ %indvars.iv.next37 = add nuw nsw i64 %indvars.iv36, 1
+ %lftr.wideiv38 = trunc i64 %indvars.iv.next37 to i32
+ %exitcond39 = icmp eq i32 %lftr.wideiv38, %N
+ br i1 %exitcond39, label %for.inc17, label %for.body6.lr.ph
+
+for.inc17: ; preds = %for.cond4.for.inc14_crit_edge
+ %indvars.iv.next41 = add nuw nsw i64 %indvars.iv40, 1
+ %lftr.wideiv42 = trunc i64 %indvars.iv.next41 to i32
+ %exitcond43 = icmp eq i32 %lftr.wideiv42, %N
+ br i1 %exitcond43, label %for.end19, label %for.cond4.preheader.preheader
+
+for.end19: ; preds = %for.inc17, %entry
+ ret void
+}
+
+;; Loop is interchanged check that the phi nodes are split and the promoted value is used instead of the reduction phi.
+; CHECK-LABEL: @reduction_02
+; CHECK: for.body6: ; preds = %for.body6.preheader, %for.body6.split
+; CHECK: %indvars.iv = phi i64 [ %indvars.iv.next, %for.body6.split ], [ 1, %for.body6.preheader ]
+; CHECK: br label %for.cond4.preheader.preheader.preheader
+; CHECK: %add13 = add nsw i32 %Y.promoted
+
+
+;; Not tightly nested. Do not interchange.
+;; for( int i=1;i<N;i++)
+;; for( int j=1;j<N;j++) {
+;; for( int k=1;k<N;k++) {
+;; X+=A[k][j];
+;; }
+;; Y+=B[j][i];
+;; }
+define void @reduction_03(i32 %N) {
+entry:
+ %cmp35 = icmp sgt i32 %N, 1
+ br i1 %cmp35, label %for.cond4.preheader.lr.ph, label %for.end19
+
+for.cond4.preheader.lr.ph: ; preds = %entry, %for.cond1.for.inc17_crit_edge
+ %indvars.iv41 = phi i64 [ %indvars.iv.next42, %for.cond1.for.inc17_crit_edge ], [ 1, %entry ]
+ %Y.promoted = load i32, i32* @Y
+ br label %for.body6.lr.ph
+
+for.body6.lr.ph: ; preds = %for.cond4.preheader.lr.ph, %for.cond4.for.end_crit_edge
+ %indvars.iv37 = phi i64 [ 1, %for.cond4.preheader.lr.ph ], [ %indvars.iv.next38, %for.cond4.for.end_crit_edge ]
+ %add1334 = phi i32 [ %Y.promoted, %for.cond4.preheader.lr.ph ], [ %add13, %for.cond4.for.end_crit_edge ]
+ %X.promoted = load i32, i32* @X
+ br label %for.body6
+
+for.body6: ; preds = %for.body6, %for.body6.lr.ph
+ %indvars.iv = phi i64 [ 1, %for.body6.lr.ph ], [ %indvars.iv.next, %for.body6 ]
+ %add31 = phi i32 [ %X.promoted, %for.body6.lr.ph ], [ %add, %for.body6 ]
+ %arrayidx8 = getelementptr inbounds [500 x [500 x i32]], [500 x [500 x i32]]* @A, i64 0, i64 %indvars.iv, i64 %indvars.iv37
+ %0 = load i32, i32* %arrayidx8
+ %add = add nsw i32 %add31, %0
+ %indvars.iv.next = add nuw nsw 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.cond4.for.end_crit_edge, label %for.body6
+
+for.cond4.for.end_crit_edge: ; preds = %for.body6
+ store i32 %add, i32* @X
+ %arrayidx12 = getelementptr inbounds [500 x [500 x i32]], [500 x [500 x i32]]* @B, i64 0, i64 %indvars.iv37, i64 %indvars.iv41
+ %1 = load i32, i32* %arrayidx12
+ %add13 = add nsw i32 %add1334, %1
+ %indvars.iv.next38 = add nuw nsw i64 %indvars.iv37, 1
+ %lftr.wideiv39 = trunc i64 %indvars.iv.next38 to i32
+ %exitcond40 = icmp eq i32 %lftr.wideiv39, %N
+ br i1 %exitcond40, label %for.cond1.for.inc17_crit_edge, label %for.body6.lr.ph
+
+for.cond1.for.inc17_crit_edge: ; preds = %for.cond4.for.end_crit_edge
+ store i32 %add13, i32* @Y
+ %indvars.iv.next42 = add nuw nsw i64 %indvars.iv41, 1
+ %lftr.wideiv43 = trunc i64 %indvars.iv.next42 to i32
+ %exitcond44 = icmp eq i32 %lftr.wideiv43, %N
+ br i1 %exitcond44, label %for.end19, label %for.cond4.preheader.lr.ph
+
+for.end19: ; preds = %for.cond1.for.inc17_crit_edge, %entry
+ ret void
+}
+;; Not tightly nested. Do not interchange.
+;; Not interchanged hence the phi's in the inner loop will not be split. Check for the same.
+; CHECK-LABEL: @reduction_03
+; CHECK: for.body6: ; preds = %for.body6.preheader, %for.body6
+; CHECK: %indvars.iv = phi i64 [ %indvars.iv.next, %for.body6 ], [ 1, %for.body6.preheader ]
+; CHECK: %add31 = phi i32 [ %add, %for.body6 ], [ %X.promoted, %for.body6.preheader ]
+
+
+
+;; Multiple use of reduction not safe. Do not interchange.
+;; for( int i=1;i<N;i++)
+;; for( int j=1;j<N;j++)
+;; for( int k=1;k<N;k++) {
+;; X+=A[k][j];
+;; Y+=X;
+;; }
+define void @reduction_04(i32 %N) {
+entry:
+ %cmp28 = icmp sgt i32 %N, 1
+ br i1 %cmp28, label %for.cond4.preheader.preheader, label %for.end15
+
+for.cond4.preheader.preheader: ; preds = %entry, %for.inc13
+ %i.029 = phi i32 [ %inc14, %for.inc13 ], [ 1, %entry ]
+ br label %for.body6.lr.ph
+
+for.body6.lr.ph: ; preds = %for.cond4.for.inc10_crit_edge, %for.cond4.preheader.preheader
+ %indvars.iv30 = phi i64 [ %indvars.iv.next31, %for.cond4.for.inc10_crit_edge ], [ 1, %for.cond4.preheader.preheader ]
+ %X.promoted = load i32, i32* @X
+ %Y.promoted = load i32, i32* @Y
+ br label %for.body6
+
+for.body6: ; preds = %for.body6, %for.body6.lr.ph
+ %indvars.iv = phi i64 [ 1, %for.body6.lr.ph ], [ %indvars.iv.next, %for.body6 ]
+ %add925 = phi i32 [ %Y.promoted, %for.body6.lr.ph ], [ %add9, %for.body6 ]
+ %add24 = phi i32 [ %X.promoted, %for.body6.lr.ph ], [ %add, %for.body6 ]
+ %arrayidx8 = getelementptr inbounds [500 x [500 x i32]], [500 x [500 x i32]]* @A, i64 0, i64 %indvars.iv, i64 %indvars.iv30
+ %0 = load i32, i32* %arrayidx8
+ %add = add nsw i32 %add24, %0
+ %add9 = add nsw i32 %add925, %add
+ %indvars.iv.next = add nuw nsw 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.cond4.for.inc10_crit_edge, label %for.body6
+
+for.cond4.for.inc10_crit_edge: ; preds = %for.body6
+ store i32 %add, i32* @X
+ store i32 %add9, i32* @Y
+ %indvars.iv.next31 = add nuw nsw i64 %indvars.iv30, 1
+ %lftr.wideiv32 = trunc i64 %indvars.iv.next31 to i32
+ %exitcond33 = icmp eq i32 %lftr.wideiv32, %N
+ br i1 %exitcond33, label %for.inc13, label %for.body6.lr.ph
+
+for.inc13: ; preds = %for.cond4.for.inc10_crit_edge
+ %inc14 = add nuw nsw i32 %i.029, 1
+ %exitcond34 = icmp eq i32 %inc14, %N
+ br i1 %exitcond34, label %for.end15, label %for.cond4.preheader.preheader
+
+for.end15: ; preds = %for.inc13, %entry
+ ret void
+}
+;; Not interchanged hence the phi's in the inner loop will not be split. Check for the same.
+; CHECK-LABEL: @reduction_04
+; CHECK: for.body6: ; preds = %for.body6.preheader, %for.body6
+; CHECK: %indvars.iv = phi i64 [ %indvars.iv.next, %for.body6 ], [ 1, %for.body6.preheader ]
+; CHECK: %add925 = phi i32 [ %add9, %for.body6 ], [ %Y.promoted, %for.body6.preheader ]