[TTI] getOperandInfo - a broadcast shuffle means the result is OK_UniformValue
llvm-svn: 346868
diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
index 25ebcde..79fe6dc 100644
--- a/llvm/lib/Analysis/TargetTransformInfo.cpp
+++ b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -399,6 +399,13 @@
return OK_UniformConstantValue;
}
+ // A broadcast shuffle creates a uniform value.
+ // TODO: Add support for non-zero index broadcasts.
+ // TODO: Add support for different source vector width.
+ if (auto *ShuffleInst = dyn_cast<ShuffleVectorInst>(V))
+ if (ShuffleInst->isZeroEltSplat())
+ OpInfo = OK_UniformValue;
+
const Value *Splat = getSplatValue(V);
// Check for a splat of a constant or for a non uniform vector of constants