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-rw-r--r--lib/Transforms/Vectorize/SLPVectorizer.cpp8
-rw-r--r--test/Transforms/SLPVectorizer/X86/reduction2.ll4
2 files changed, 9 insertions, 3 deletions
diff --git a/lib/Transforms/Vectorize/SLPVectorizer.cpp b/lib/Transforms/Vectorize/SLPVectorizer.cpp
index c1accd32c5..50e37e9916 100644
--- a/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -898,8 +898,12 @@ int BoUpSLP::getTreeCost() {
DEBUG(dbgs() << "SLP: Calculating cost for tree of size " <<
VectorizableTree.size() << ".\n");
- if (!VectorizableTree.size()) {
- assert(!ExternalUses.size() && "We should not have any external users");
+ // Don't vectorize tiny trees. Small load/store chains or consecutive stores
+ // of constants will be vectoried in SelectionDAG in MergeConsecutiveStores.
+ if (VectorizableTree.size() < 3) {
+ if (!VectorizableTree.size()) {
+ assert(!ExternalUses.size() && "We should not have any external users");
+ }
return 0;
}
diff --git a/test/Transforms/SLPVectorizer/X86/reduction2.ll b/test/Transforms/SLPVectorizer/X86/reduction2.ll
index 1dc77d2ef5..f21e86c564 100644
--- a/test/Transforms/SLPVectorizer/X86/reduction2.ll
+++ b/test/Transforms/SLPVectorizer/X86/reduction2.ll
@@ -16,11 +16,13 @@ define double @foo(double* nocapture %D) {
%3 = getelementptr inbounds double* %D, i32 %2
%4 = load double* %3, align 4
%A4 = fmul double %4, %4
+ %A42 = fmul double %A4, %A4
%5 = or i32 %2, 1
%6 = getelementptr inbounds double* %D, i32 %5
%7 = load double* %6, align 4
%A7 = fmul double %7, %7
- %8 = fadd double %A4, %A7
+ %A72 = fmul double %A7, %A7
+ %8 = fadd double %A42, %A72
%9 = fadd double %sum.01, %8
%10 = add nsw i32 %i.02, 1
%exitcond = icmp eq i32 %10, 100