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Codegen: [X86] preservere memory refs for folded umul_lohi 

Memory references were not being propagated for this folded load. This
prevented optimizations like LICM from hoisting the load.

Added test to verify that this allows LICM to proceed.

llvm-svn: 273617
This commit is contained in:
Kyle Butt 2016-06-23 21:40:35 +00:00
parent 178314ab52
commit 991df7889b
2 changed files with 42 additions and 3 deletions
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12
llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
View File

@ -2223,24 +2223,32 @@ void X86DAGToDAGISel::Select(SDNode *Node) {
if (foldedLoad) {
SDValue Chain;
MachineSDNode *CNode = nullptr;
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N1.getOperand(0),
InFlag };
if (MOpc == X86::MULX32rm || MOpc == X86::MULX64rm) {
SDVTList VTs = CurDAG->getVTList(NVT, NVT, MVT::Other, MVT::Glue);
SDNode *CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
ResHi = SDValue(CNode, 0);
ResLo = SDValue(CNode, 1);
Chain = SDValue(CNode, 2);
InFlag = SDValue(CNode, 3);
} else {
SDVTList VTs = CurDAG->getVTList(MVT::Other, MVT::Glue);
SDNode *CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
Chain = SDValue(CNode, 0);
InFlag = SDValue(CNode, 1);
}
// Update the chain.
ReplaceUses(N1.getValue(1), Chain);
// Record the mem-refs
LoadSDNode *LoadNode = cast<LoadSDNode>(N1);
if (LoadNode) {
MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(1);
MemOp[0] = LoadNode->getMemOperand();
CNode->setMemRefs(MemOp, MemOp + 1);
}
} else {
SDValue Ops[] = { N1, InFlag };
if (Opc == X86::MULX32rr || Opc == X86::MULX64rr) {

33
llvm/test/CodeGen/X86/hoist-invariant-load.ll
View File

@ -1,7 +1,10 @@
; REQUIRES: asserts
; RUN: llc < %s -stats -O2 2>&1 | grep "2 machine-licm"
; RUN: llc -mcpu=haswell < %s -stats -O2 2>&1 | grep "4 machine-licm.*hoisted"
; For test:
; 2 invariant loads, 1 for OBJC_SELECTOR_REFERENCES_
; and 1 for objc_msgSend from the GOT
; For test_multi_def:
; 2 invariant load (full multiply, both loads should be hoisted.)
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.7.2"
@ -29,4 +32,32 @@ for.end: ; preds = %for.body
declare i8* @objc_msgSend(i8*, i8*, ...) nonlazybind
define void @test_multi_def(i64* dereferenceable(8) %x1,
i64* dereferenceable(8) %x2,
i128* %y, i64 %count) nounwind {
entry:
br label %for.body
for.check:
%inc = add nsw i64 %i, 1
%done = icmp sge i64 %inc, %count
br i1 %done, label %exit, label %for.body
for.body:
%i = phi i64 [ 0, %entry ], [ %inc, %for.check ]
%x1_load = load i64, i64* %x1, align 8, !invariant.load !0
%x1_zext = zext i64 %x1_load to i128
%x2_load = load i64, i64* %x2, align 8, !invariant.load !0
%x2_zext = zext i64 %x2_load to i128
%x_prod = mul i128 %x1_zext, %x2_zext
%y_elem = getelementptr inbounds i128, i128* %y, i64 %i
%y_load = load i128, i128* %y_elem, align 8
%y_plus = add i128 %x_prod, %y_load
store i128 %y_plus, i128* %y_elem, align 8
br label %for.check
exit:
ret void
}
!0 = !{}