From 0f2fe74aaf47925fd1cb7aa1329244ab550096fc Mon Sep 17 00:00:00 2001 From: Quentin Colombet Date: Tue, 23 Jul 2013 22:34:47 +0000 Subject: [PATCH] [ARM][ISel] Improve the lowering of vector loads. When vectors are built from a single value, the ARM lowering issues a scalar_to_vector node. This node is then always morphed into a move from the general purpose unit to the vector unit. When the value comes from a load, this can be simplified into a vector load to the right lane. This patch changes the lowering of insert_vector_elt to expose a vector friendly pattern in this situation. This is a step toward fixing . llvm-svn: 186999 --- llvm/lib/Target/ARM/ARMISelLowering.cpp | 4 +++- llvm/test/CodeGen/ARM/vector-DAGCombine.ll | 14 ++++++++++++++ 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp index 569bead..ea13c88 100644 --- a/llvm/lib/Target/ARM/ARMISelLowering.cpp +++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp @@ -4674,7 +4674,9 @@ SDValue ARMTargetLowering::LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG, if (ValueCounts.size() == 0) return DAG.getUNDEF(VT); - if (isOnlyLowElement) + // Loads are better lowered with insert_vector_elt/ARMISD::BUILD_VECTOR. + // Keep going if we are hitting this case. + if (isOnlyLowElement && !ISD::isNormalLoad(Value.getNode())) return DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Value); unsigned EltSize = VT.getVectorElementType().getSizeInBits(); diff --git a/llvm/test/CodeGen/ARM/vector-DAGCombine.ll b/llvm/test/CodeGen/ARM/vector-DAGCombine.ll index 6d586f2..3e13819 100644 --- a/llvm/test/CodeGen/ARM/vector-DAGCombine.ll +++ b/llvm/test/CodeGen/ARM/vector-DAGCombine.ll @@ -184,3 +184,17 @@ entry: ; Function Attrs: nounwind readnone declare <8 x i16> @llvm.arm.neon.vmullu.v8i16(<8 x i8>, <8 x i8>) + +; Check that (insert_vector_elt (load)) => (vector_load). +; Thus, check that scalar_to_vector do not interfer with that. +define <8 x i16> @t4(i8* nocapture %sp0) { +; CHECK: t4 +; CHECK: vld1.32 {{{d[0-9]+}}[0]}, [r0] +entry: + %pix_sp0.0.cast = bitcast i8* %sp0 to i32* + %pix_sp0.0.copyload = load i32* %pix_sp0.0.cast, align 1 + %vec = insertelement <2 x i32> undef, i32 %pix_sp0.0.copyload, i32 0 + %0 = bitcast <2 x i32> %vec to <8 x i8> + %vmull.i = tail call <8 x i16> @llvm.arm.neon.vmullu.v8i16(<8 x i8> %0, <8 x i8> %0) + ret <8 x i16> %vmull.i +} -- 2.7.4