[LV] Allow reductions that have several uses outside the loop
We currently check whether a reduction has a single outside user. We don't
really need to require that - we just need to make sure a single value is
used externally. The number of external users of that value shouldn't actually
matter.
Differential Revision: https://reviews.llvm.org/D28830
llvm-svn: 292424
diff --git a/llvm/test/Transforms/LoopVectorize/reduction.ll b/llvm/test/Transforms/LoopVectorize/reduction.ll
index 4b300e04..f521b62 100644
--- a/llvm/test/Transforms/LoopVectorize/reduction.ll
+++ b/llvm/test/Transforms/LoopVectorize/reduction.ll
@@ -493,3 +493,49 @@
%inc.2 = add nsw i32 %inc511.1.inc4.1, 2
ret i32 %inc.2
}
+
+;CHECK-LABEL: @reduction_sum_multiuse(
+;CHECK: phi <4 x i32>
+;CHECK: load <4 x i32>
+;CHECK: add <4 x i32>
+;CHECK: shufflevector <4 x i32> %{{.*}}, <4 x i32> undef, <4 x i32> <i32 2, i32 3, i32 undef, i32 undef>
+;CHECK: add <4 x i32>
+;CHECK: shufflevector <4 x i32> %{{.*}}, <4 x i32> undef, <4 x i32> <i32 1, i32 undef, i32 undef, i32 undef>
+;CHECK: add <4 x i32>
+;CHECK: extractelement <4 x i32> %{{.*}}, i32 0
+;CHECK: %sum.lcssa = phi i32 [ %[[SCALAR:.*]], %.lr.ph ], [ %[[VECTOR:.*]], %middle.block ]
+;CHECK: %sum.copy = phi i32 [ %[[SCALAR]], %.lr.ph ], [ %[[VECTOR]], %middle.block ]
+;CHECK: ret i32
+define i32 @reduction_sum_multiuse(i32 %n, i32* noalias nocapture %A, i32* noalias nocapture %B) {
+ %1 = icmp sgt i32 %n, 0
+ br i1 %1, label %.lr.ph.preheader, label %end
+.lr.ph.preheader: ; preds = %0
+ br label %.lr.ph
+
+.lr.ph: ; preds = %0, %.lr.ph
+ %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %.lr.ph.preheader ]
+ %sum.02 = phi i32 [ %9, %.lr.ph ], [ 0, %.lr.ph.preheader ]
+ %2 = getelementptr inbounds i32, i32* %A, i64 %indvars.iv
+ %3 = load i32, i32* %2, align 4
+ %4 = getelementptr inbounds i32, i32* %B, i64 %indvars.iv
+ %5 = load i32, i32* %4, align 4
+ %6 = trunc i64 %indvars.iv to i32
+ %7 = add i32 %sum.02, %6
+ %8 = add i32 %7, %3
+ %9 = add i32 %8, %5
+ %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 %._crit_edge, label %.lr.ph
+
+._crit_edge: ; preds = %.lr.ph, %0
+ %sum.lcssa = phi i32 [ %9, %.lr.ph ]
+ %sum.copy = phi i32 [ %9, %.lr.ph ]
+ br label %end
+
+end:
+ %f1 = phi i32 [ 0, %0 ], [ %sum.lcssa, %._crit_edge ]
+ %f2 = phi i32 [ 0, %0 ], [ %sum.copy, %._crit_edge ]
+ %final = add i32 %f1, %f2
+ ret i32 %final
+}