//===----------------------------------------------------------------------===//
Value *InnerLoopVectorizer::getBroadcastInstrs(Value *V) {
- // We need to place the broadcast of invariant variables outside the loop.
+ // We need to place the broadcast of invariant variables outside the loop,
+ // but only if it's proven safe to do so. Else, broadcast will be inside
+ // vector loop body.
Instruction *Instr = dyn_cast<Instruction>(V);
- bool NewInstr = (Instr && Instr->getParent() == LoopVectorBody);
- bool Invariant = OrigLoop->isLoopInvariant(V) && !NewInstr;
-
+ bool SafeToHoist = OrigLoop->isLoopInvariant(V) &&
+ (!Instr ||
+ DT->dominates(Instr->getParent(), LoopVectorPreHeader));
// Place the code for broadcasting invariant variables in the new preheader.
IRBuilder<>::InsertPointGuard Guard(Builder);
- if (Invariant)
+ if (SafeToHoist)
Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
// Broadcast the scalar into all locations in the vector.
--- /dev/null
+; RUN: opt -passes='loop-vectorize' -force-vector-width=2 -S < %s | FileCheck %s
+;
+; Forcing VF=2 to trigger vector code gen
+;
+; This is a test case that let's vectorizer's code gen to generate
+; more than one BasicBlocks in the loop body (emulated masked scatter)
+; for those targets that do not support masked scatter. Broadcast
+; code generation was previously dependent on loop body being
+; a single basic block and this test case exposed incorrect code gen
+; resulting in an assert in IL verification. Test passes if IL verification
+; does not fail.
+;
+; Performing minimal check in the output to ensure the loop is actually
+; vectorized.
+;
+; CHECK: vector.body
+
+@a = external global [2 x i16], align 1
+
+define void @f1() {
+entry:
+ br label %for.body
+
+for.body: ; preds = %land.end, %entry
+ %0 = phi i32 [ undef, %entry ], [ %dec, %land.end ]
+ br i1 undef, label %land.end, label %land.rhs
+
+land.rhs: ; preds = %for.body
+ %1 = load i32, i32* undef, align 1
+ br label %land.end
+
+land.end: ; preds = %land.rhs, %for.body
+ %2 = trunc i32 %0 to i16
+ %arrayidx = getelementptr inbounds [2 x i16], [2 x i16]* @a, i16 0, i16 %2
+ store i16 undef, i16* %arrayidx, align 1
+ %dec = add nsw i32 %0, -1
+ %cmp = icmp sgt i32 %0, 1
+ br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge
+
+for.cond.for.end_crit_edge: ; preds = %land.end
+ unreachable
+}