[llvm-commits] [llvm] r147283 - in /llvm/trunk: lib/CodeGen/SelectionDAG/DAGCombiner.cpp test/CodeGen/ARM/2011-11-29-128bitArithmetics.ll test/CodeGen/X86/2011-12-26-extractelement-duplicate-load.ll
Eli Friedman
eli.friedman at gmail.com
Mon Dec 26 14:49:33 PST 2011
Author: efriedma
Date: Mon Dec 26 16:49:32 2011
New Revision: 147283
URL: http://llvm.org/viewvc/llvm-project?rev=147283&view=rev
Log:
Make sure DAGCombiner doesn't introduce multiple loads from the same memory location. PR10747, part 2.
Added:
llvm/trunk/test/CodeGen/X86/2011-12-26-extractelement-duplicate-load.ll
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
llvm/trunk/test/CodeGen/ARM/2011-11-29-128bitArithmetics.ll
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=147283&r1=147282&r2=147283&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Mon Dec 26 16:49:32 2011
@@ -6905,6 +6905,10 @@
EVT LVT = ExtVT;
if (InVec.getOpcode() == ISD::BITCAST) {
+ // Don't duplicate a load with other uses.
+ if (!InVec.hasOneUse())
+ return SDValue();
+
EVT BCVT = InVec.getOperand(0).getValueType();
if (!BCVT.isVector() || ExtVT.bitsGT(BCVT.getVectorElementType()))
return SDValue();
@@ -6922,12 +6926,20 @@
} else if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR &&
InVec.getOperand(0).getValueType() == ExtVT &&
ISD::isNormalLoad(InVec.getOperand(0).getNode())) {
+ // Don't duplicate a load with other uses.
+ if (!InVec.hasOneUse())
+ return SDValue();
+
LN0 = cast<LoadSDNode>(InVec.getOperand(0));
} else if ((SVN = dyn_cast<ShuffleVectorSDNode>(InVec))) {
// (vextract (vector_shuffle (load $addr), v2, <1, u, u, u>), 1)
// =>
// (load $addr+1*size)
+ // Don't duplicate a load with other uses.
+ if (!InVec.hasOneUse())
+ return SDValue();
+
// If the bit convert changed the number of elements, it is unsafe
// to examine the mask.
if (BCNumEltsChanged)
@@ -6938,14 +6950,21 @@
int Idx = (Elt > (int)NumElems) ? -1 : SVN->getMaskElt(Elt);
InVec = (Idx < (int)NumElems) ? InVec.getOperand(0) : InVec.getOperand(1);
- if (InVec.getOpcode() == ISD::BITCAST)
+ if (InVec.getOpcode() == ISD::BITCAST) {
+ // Don't duplicate a load with other uses.
+ if (!InVec.hasOneUse())
+ return SDValue();
+
InVec = InVec.getOperand(0);
+ }
if (ISD::isNormalLoad(InVec.getNode())) {
LN0 = cast<LoadSDNode>(InVec);
Elt = (Idx < (int)NumElems) ? Idx : Idx - (int)NumElems;
}
}
+ // Make sure we found a non-volatile load and the extractelement is
+ // the only use.
if (!LN0 || !LN0->hasNUsesOfValue(1,0) || LN0->isVolatile())
return SDValue();
@@ -6982,6 +7001,9 @@
// The replacement we need to do here is a little tricky: we need to
// replace an extractelement of a load with a load.
// Use ReplaceAllUsesOfValuesWith to do the replacement.
+ // Note that this replacement assumes that the extractvalue is the only
+ // use of the load; that's okay because we don't want to perform this
+ // transformation in other cases anyway.
SDValue Load = DAG.getLoad(LVT, N->getDebugLoc(), LN0->getChain(), NewPtr,
LN0->getPointerInfo().getWithOffset(PtrOff),
LN0->isVolatile(), LN0->isNonTemporal(),
Modified: llvm/trunk/test/CodeGen/ARM/2011-11-29-128bitArithmetics.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/2011-11-29-128bitArithmetics.ll?rev=147283&r1=147282&r2=147283&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/2011-11-29-128bitArithmetics.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/2011-11-29-128bitArithmetics.ll Mon Dec 26 16:49:32 2011
@@ -8,11 +8,11 @@
; CHECK: movw r1, :lower16:{{.*}}
; CHECK: movt r1, :upper16:{{.*}}
-; CHECK: vldmia r1, {[[short0:s[0-9]+]], [[short1:s[0-9]+]], [[short2:s[0-9]+]], [[short3:s[0-9]+]]}
-; CHECK: vsqrt.f32 {{s[0-9]+}}, [[short3]]
-; CHECK: vsqrt.f32 {{s[0-9]+}}, [[short2]]
-; CHECK: vsqrt.f32 {{s[0-9]+}}, [[short1]]
-; CHECK: vsqrt.f32 {{s[0-9]+}}, [[short0]]
+; CHECK: vldmia r1
+; CHECK: vsqrt.f32 {{s[0-9]+}}, {{s[0-9]+}}
+; CHECK: vsqrt.f32 {{s[0-9]+}}, {{s[0-9]+}}
+; CHECK: vsqrt.f32 {{s[0-9]+}}, {{s[0-9]+}}
+; CHECK: vsqrt.f32 {{s[0-9]+}}, {{s[0-9]+}}
; CHECK: vstmia {{.*}}
L.entry:
Added: llvm/trunk/test/CodeGen/X86/2011-12-26-extractelement-duplicate-load.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2011-12-26-extractelement-duplicate-load.ll?rev=147283&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/2011-12-26-extractelement-duplicate-load.ll (added)
+++ llvm/trunk/test/CodeGen/X86/2011-12-26-extractelement-duplicate-load.ll Mon Dec 26 16:49:32 2011
@@ -0,0 +1,16 @@
+; RUN: llc -march=x86-64 -mattr=-sse42,+sse41 < %s | FileCheck %s
+; Make sure we don't load from the location pointed to by %p
+; twice: it has non-obvious performance implications, and
+; the relevant transformation doesn't know how to update
+; the chains correctly.
+; PR10747
+
+; CHECK: test:
+; CHECK: pextrd $2, %xmm
+define <4 x i32> @test(<4 x i32>* %p) {
+ %v = load <4 x i32>* %p
+ %e = extractelement <4 x i32> %v, i32 2
+ %cmp = icmp eq i32 %e, 3
+ %sel = select i1 %cmp, <4 x i32> %v, <4 x i32> zeroinitializer
+ ret <4 x i32> %sel
+}
More information about the llvm-commits
mailing list