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[X86] Use StackArgTokenFactor for all stores when setting up tail calls. #126244

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Merged
merged 1 commit into from
Feb 10, 2025
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[X86] Use StackArgTokenFactor for all stores when setting up tail calls. #126244

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20 changes: 10 additions & 10 deletions llvm/lib/Target/X86/X86ISelLoweringCall.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2326,12 +2326,13 @@ X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
// shuffling arguments passed in memory.
if (!IsSibcall && isTailCall) {
// Force all the incoming stack arguments to be loaded from the stack
// before any new outgoing arguments are stored to the stack, because the
// outgoing stack slots may alias the incoming argument stack slots, and
// the alias isn't otherwise explicit. This is slightly more conservative
// than necessary, because it means that each store effectively depends
// on every argument instead of just those arguments it would clobber.
SDValue ArgChain = DAG.getStackArgumentTokenFactor(Chain);
// before any new outgoing arguments or the return address are stored to the
// stack, because the outgoing stack slots may alias the incoming argument
// stack slots, and the alias isn't otherwise explicit. This is slightly
// more conservative than necessary, because it means that each store
// effectively depends on every argument instead of just those arguments it
// would clobber.
Chain = DAG.getStackArgumentTokenFactor(Chain);

SmallVector<SDValue, 8> MemOpChains2;
SDValue FIN;
Expand Down Expand Up @@ -2373,13 +2374,12 @@ X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
Source = DAG.getNode(ISD::ADD, dl, getPointerTy(DAG.getDataLayout()),
StackPtr, Source);

MemOpChains2.push_back(CreateCopyOfByValArgument(Source, FIN,
ArgChain,
Flags, DAG, dl));
MemOpChains2.push_back(
CreateCopyOfByValArgument(Source, FIN, Chain, Flags, DAG, dl));
} else {
// Store relative to framepointer.
MemOpChains2.push_back(DAG.getStore(
ArgChain, dl, Arg, FIN,
Chain, dl, Arg, FIN,
MachinePointerInfo::getFixedStack(DAG.getMachineFunction(), FI)));
}
}
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4 changes: 2 additions & 2 deletions llvm/test/CodeGen/X86/swifttailcc-store-ret-address-aliasing-stack-slot.ll
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Expand Up @@ -24,9 +24,9 @@ define swifttailcc void @test(ptr %0, ptr swiftasync %1, i64 %2, i64 %3, ptr %4,
; CHECK-NEXT: movq {{[0-9]+}}(%rsp), %r15
; CHECK-NEXT: callq _foo
; CHECK-NEXT: movq %r14, (%rax)
; CHECK-NEXT: movl [[OFF:[0-9]+]](%rsp), %edx
; CHECK-NEXT: movq {{[0-9]+}}(%rsp), %rcx
; CHECK-NEXT: movq %rcx, [[OFF:[0-9]+]](%rsp)
; CHECK-NEXT: movl [[OFF]](%rsp), %edx
; CHECK-NEXT: movq %rcx, [[OFF]](%rsp)
; CHECK-NEXT: movq %rax, %r14
; CHECK-NEXT: movq %r13, %rdi
; CHECK-NEXT: movq %r15, %rsi
Expand Down