[llvm] r182102 - X86: Make shuffle -> shift conversion more aggressive about undefs.
Benjamin Kramer
benny.kra at googlemail.com
Fri May 17 07:48:35 PDT 2013
Author: d0k
Date: Fri May 17 09:48:34 2013
New Revision: 182102
URL: http://llvm.org/viewvc/llvm-project?rev=182102&view=rev
Log:
X86: Make shuffle -> shift conversion more aggressive about undefs.
Shuffles that only move an element into position 0 of the vector are common in
the output of the loop vectorizer and often generate suboptimal code when SSSE3
is not available. Lower them to vector shifts if possible.
We still prefer palignr over psrldq because it has higher throughput on
sandybridge.
Modified:
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
llvm/trunk/test/CodeGen/X86/avx-vpermil.ll
llvm/trunk/test/CodeGen/X86/vec_insert-5.ll
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=182102&r1=182101&r2=182102&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Fri May 17 09:48:34 2013
@@ -4756,19 +4756,27 @@ static SDValue getShuffleScalarElt(SDNod
/// getNumOfConsecutiveZeros - Return the number of elements of a vector
/// shuffle operation which come from a consecutively from a zero. The
/// search can start in two different directions, from left or right.
-static
-unsigned getNumOfConsecutiveZeros(ShuffleVectorSDNode *SVOp, unsigned NumElems,
- bool ZerosFromLeft, SelectionDAG &DAG) {
- unsigned i;
- for (i = 0; i != NumElems; ++i) {
- unsigned Index = ZerosFromLeft ? i : NumElems-i-1;
+/// We count undefs as zeros until PreferredNum is reached.
+static unsigned getNumOfConsecutiveZeros(ShuffleVectorSDNode *SVOp,
+ unsigned NumElems, bool ZerosFromLeft,
+ SelectionDAG &DAG,
+ unsigned PreferredNum = -1U) {
+ unsigned NumZeros = 0;
+ for (unsigned i = 0; i != NumElems; ++i) {
+ unsigned Index = ZerosFromLeft ? i : NumElems - i - 1;
SDValue Elt = getShuffleScalarElt(SVOp, Index, DAG, 0);
- if (!(Elt.getNode() &&
- (Elt.getOpcode() == ISD::UNDEF || X86::isZeroNode(Elt))))
+ if (!Elt.getNode())
+ break;
+
+ if (X86::isZeroNode(Elt))
+ ++NumZeros;
+ else if (Elt.getOpcode() == ISD::UNDEF) // Undef as zero up to PreferredNum.
+ NumZeros = std::min(NumZeros + 1, PreferredNum);
+ else
break;
}
- return i;
+ return NumZeros;
}
/// isShuffleMaskConsecutive - Check if the shuffle mask indicies [MaskI, MaskE)
@@ -4806,8 +4814,9 @@ bool isShuffleMaskConsecutive(ShuffleVec
static bool isVectorShiftRight(ShuffleVectorSDNode *SVOp, SelectionDAG &DAG,
bool &isLeft, SDValue &ShVal, unsigned &ShAmt) {
unsigned NumElems = SVOp->getValueType(0).getVectorNumElements();
- unsigned NumZeros = getNumOfConsecutiveZeros(SVOp, NumElems,
- false /* check zeros from right */, DAG);
+ unsigned NumZeros = getNumOfConsecutiveZeros(
+ SVOp, NumElems, false /* check zeros from right */, DAG,
+ SVOp->getMaskElt(0));
unsigned OpSrc;
if (!NumZeros)
@@ -4839,8 +4848,9 @@ static bool isVectorShiftRight(ShuffleVe
static bool isVectorShiftLeft(ShuffleVectorSDNode *SVOp, SelectionDAG &DAG,
bool &isLeft, SDValue &ShVal, unsigned &ShAmt) {
unsigned NumElems = SVOp->getValueType(0).getVectorNumElements();
- unsigned NumZeros = getNumOfConsecutiveZeros(SVOp, NumElems,
- true /* check zeros from left */, DAG);
+ unsigned NumZeros = getNumOfConsecutiveZeros(
+ SVOp, NumElems, true /* check zeros from left */, DAG,
+ NumElems - SVOp->getMaskElt(NumElems - 1) - 1);
unsigned OpSrc;
if (!NumZeros)
@@ -6871,6 +6881,11 @@ X86TargetLowering::LowerVECTOR_SHUFFLE(S
TargetMask, DAG);
}
+ if (isPALIGNRMask(M, VT, Subtarget))
+ return getTargetShuffleNode(X86ISD::PALIGNR, dl, VT, V1, V2,
+ getShufflePALIGNRImmediate(SVOp),
+ DAG);
+
// Check if this can be converted into a logical shift.
bool isLeft = false;
unsigned ShAmt = 0;
@@ -6988,11 +7003,6 @@ X86TargetLowering::LowerVECTOR_SHUFFLE(S
// inlined here right now to enable us to directly emit target specific
// nodes, and remove one by one until they don't return Op anymore.
- if (isPALIGNRMask(M, VT, Subtarget))
- return getTargetShuffleNode(X86ISD::PALIGNR, dl, VT, V1, V2,
- getShufflePALIGNRImmediate(SVOp),
- DAG);
-
if (ShuffleVectorSDNode::isSplatMask(&M[0], VT) &&
SVOp->getSplatIndex() == 0 && V2IsUndef) {
if (VT == MVT::v2f64 || VT == MVT::v2i64)
Modified: llvm/trunk/test/CodeGen/X86/avx-vpermil.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/avx-vpermil.ll?rev=182102&r1=182101&r2=182102&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/avx-vpermil.ll (original)
+++ llvm/trunk/test/CodeGen/X86/avx-vpermil.ll Fri May 17 09:48:34 2013
@@ -46,7 +46,7 @@ entry:
}
; CHECK: palignr $8
-; CHECK: psrldq $8
+; CHECK: palignr $8
define <8 x float> @funcF(<8 x float> %a) nounwind uwtable readnone ssp {
entry:
%shuffle = shufflevector <8 x float> %a, <8 x float> zeroinitializer, <8 x i32> <i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9>
Modified: llvm/trunk/test/CodeGen/X86/vec_insert-5.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/vec_insert-5.ll?rev=182102&r1=182101&r2=182102&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/vec_insert-5.ll (original)
+++ llvm/trunk/test/CodeGen/X86/vec_insert-5.ll Fri May 17 09:48:34 2013
@@ -1,4 +1,4 @@
-; RUN: llc < %s -march=x86 -mattr=+sse2 | FileCheck %s
+; RUN: llc < %s -march=x86 -mattr=+sse2,+ssse3 | FileCheck %s
; There are no MMX operations in @t1
define void @t1(i32 %a, x86_mmx* %P) nounwind {
@@ -41,3 +41,27 @@ define <4 x float> @t4(<4 x float>* %P)
; CHECK: t4:
; CHECK: psrldq $12
}
+
+define <16 x i8> @t5(<16 x i8> %x) nounwind {
+ %s = shufflevector <16 x i8> %x, <16 x i8> zeroinitializer, <16 x i32> <i32 1, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 17>
+ ret <16 x i8> %s
+
+; CHECK: t5:
+; CHECK: psrldq $1
+}
+
+define <16 x i8> @t6(<16 x i8> %x) nounwind {
+ %s = shufflevector <16 x i8> %x, <16 x i8> undef, <16 x i32> <i32 1, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+ ret <16 x i8> %s
+
+; CHECK: t6:
+; CHECK: palignr $1
+}
+
+define <16 x i8> @t7(<16 x i8> %x) nounwind {
+ %s = shufflevector <16 x i8> %x, <16 x i8> undef, <16 x i32> <i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 1, i32 2>
+ ret <16 x i8> %s
+
+; CHECK: t7:
+; CHECK: pslldq $13
+}
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