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[Clang] Attribute NoFPClass should not prevent tail call optimization. #116741

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merged 2 commits into from
Nov 23, 2024
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[Clang] Attribute NoFPClass should not prevent tail call optimization. #116741

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1599ddd
[Clang] Attribute NoFPClass should not prevent tail call optimization.
felix642 Nov 19, 2024
02089e2
fixup! [Clang] Attribute NoFPClass should not prevent tail call optim…
felix642 Nov 23, 2024
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8 changes: 4 additions & 4 deletions llvm/lib/CodeGen/Analysis.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -596,10 +596,10 @@ bool llvm::attributesPermitTailCall(const Function *F, const Instruction *I,

// Following attributes are completely benign as far as calling convention
// goes, they shouldn't affect whether the call is a tail call.
for (const auto &Attr :
{Attribute::Alignment, Attribute::Dereferenceable,
Attribute::DereferenceableOrNull, Attribute::NoAlias,
Attribute::NonNull, Attribute::NoUndef, Attribute::Range}) {
for (const auto &Attr : {Attribute::Alignment, Attribute::Dereferenceable,
Attribute::DereferenceableOrNull, Attribute::NoAlias,
Attribute::NonNull, Attribute::NoUndef,
Attribute::Range, Attribute::NoFPClass}) {
CallerAttrs.removeAttribute(Attr);
CalleeAttrs.removeAttribute(Attr);
}
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8 changes: 4 additions & 4 deletions llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
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Expand Up @@ -61,10 +61,10 @@ bool TargetLowering::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
// the return. Ignore following attributes because they don't affect the
// call sequence.
AttrBuilder CallerAttrs(F.getContext(), F.getAttributes().getRetAttrs());
for (const auto &Attr :
{Attribute::Alignment, Attribute::Dereferenceable,
Attribute::DereferenceableOrNull, Attribute::NoAlias,
Attribute::NonNull, Attribute::NoUndef, Attribute::Range})
for (const auto &Attr : {Attribute::Alignment, Attribute::Dereferenceable,
Attribute::DereferenceableOrNull, Attribute::NoAlias,
Attribute::NonNull, Attribute::NoUndef,
Attribute::Range, Attribute::NoFPClass})
CallerAttrs.removeAttribute(Attr);

if (CallerAttrs.hasAttributes())
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13 changes: 13 additions & 0 deletions llvm/test/CodeGen/X86/tailcall-nofpclass.ll
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@@ -0,0 +1,13 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
; RUN: llc -mtriple=x86_64-linux < %s | FileCheck %s

; Ensures that taillcall optimization can still be
; performed when nofpclass is used.

define noundef nofpclass(nan inf) float @_Z3foof(float noundef nofpclass(nan inf) %0) {
; CHECK-LABEL: _Z3foof:
; CHECK: # %bb.0:
; CHECK-NEXT: jmp expf@PLT # TAILCALL
%2 = tail call float @llvm.exp.f32(float %0)
ret float %2
}
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