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arsenmarsenm
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IR/AMDGPU: Autoupgrade amdgpu-unsafe-fp-atomics attribute (#101698)
Delete the attribute and annotate any atomicrmw instructions in the function with new metadata.
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‎llvm/lib/IR/AutoUpgrade.cpp

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@@ -5272,6 +5272,22 @@ struct StrictFPUpgradeVisitor : public InstVisitor<StrictFPUpgradeVisitor> {
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Call.addFnAttr(Attribute::NoBuiltin);
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}
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};
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/// Replace "amdgpu-unsafe-fp-atomics" metadata with atomicrmw metadata
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struct AMDGPUUnsafeFPAtomicsUpgradeVisitor
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: public InstVisitor<AMDGPUUnsafeFPAtomicsUpgradeVisitor> {
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AMDGPUUnsafeFPAtomicsUpgradeVisitor() = default;
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void visitAtomicRMWInst(AtomicRMWInst &RMW) {
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if (!RMW.isFloatingPointOperation())
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return;
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MDNode *Empty = MDNode::get(RMW.getContext(), {});
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RMW.setMetadata("amdgpu.no.fine.grained.host.memory", Empty);
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RMW.setMetadata("amdgpu.no.remote.memory.access", Empty);
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RMW.setMetadata("amdgpu.ignore.denormal.mode", Empty);
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}
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};
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} // namespace
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void llvm::UpgradeFunctionAttributes(Function &F) {
@@ -5294,6 +5310,24 @@ void llvm::UpgradeFunctionAttributes(Function &F) {
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F.setSection(A.getValueAsString());
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F.removeFnAttr("implicit-section-name");
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}
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if (!F.empty()) {
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// For some reason this is called twice, and the first time is before any
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// instructions are loaded into the body.
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if (Attribute A = F.getFnAttribute("amdgpu-unsafe-fp-atomics");
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A.isValid()) {
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if (A.getValueAsBool()) {
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AMDGPUUnsafeFPAtomicsUpgradeVisitor Visitor;
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Visitor.visit(F);
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}
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// We will leave behind dead attribute uses on external declarations, but
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// clang never added these to declarations anyway.
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F.removeFnAttr("amdgpu-unsafe-fp-atomics");
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}
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}
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}
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static bool isOldLoopArgument(Metadata *MD) {

‎llvm/test/Bitcode/amdgpu-unsafe-fp-atomics-upgrade.ll

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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals all --version 4
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; RUN: llvm-as < %s | llvm-dis | FileCheck %s
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; amdgpu-unsafe-fp-atomics attribute should be removed and replaced
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; with metadata attached to any atomicrmw with floating-point
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; operations.
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; Maybe the attribute should be dropped from declarations, but it
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; didn't do anything on one and clang never added it.
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declare void @unsafe_fp_atomics_true_decl() "amdgpu-unsafe-fp-atomics"="true"
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declare void @unsafe_fp_atomics_false_decl() "amdgpu-unsafe-fp-atomics"="false"
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; Delete the attribute and replace with the most aggressive metadata possible
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define void @unsafe_fp_atomics_true(ptr addrspace(1) %ptr, float %val, i32 %ival, <2 x half> %vval) "amdgpu-unsafe-fp-atomics"="true" {
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; CHECK-LABEL: define void @unsafe_fp_atomics_true(
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; CHECK-SAME: ptr addrspace(1) [[PTR:%.*]], float [[VAL:%.*]], i32 [[IVAL:%.*]], <2 x half> [[VVAL:%.*]]) {
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; CHECK-NEXT: [[RMW_FADD:%.*]] = atomicrmw fadd ptr addrspace(1) [[PTR]], float [[VAL]] syncscope("one-as") seq_cst, align 4, !amdgpu.no.fine.grained.host.memory [[META0:![0-9]+]], !amdgpu.no.remote.memory.access [[META0]], !amdgpu.ignore.denormal.mode [[META0]]
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; CHECK-NEXT: [[RMW_FSUB:%.*]] = atomicrmw fsub ptr addrspace(1) [[PTR]], float [[VAL]] syncscope("one-as") seq_cst, align 4, !amdgpu.no.fine.grained.host.memory [[META0]], !amdgpu.no.remote.memory.access [[META0]], !amdgpu.ignore.denormal.mode [[META0]]
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; CHECK-NEXT: [[RMW_FMIN:%.*]] = atomicrmw fmin ptr addrspace(1) [[PTR]], float [[VAL]] syncscope("one-as") seq_cst, align 4, !amdgpu.no.fine.grained.host.memory [[META0]], !amdgpu.no.remote.memory.access [[META0]], !amdgpu.ignore.denormal.mode [[META0]]
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; CHECK-NEXT: [[RMW_FMAX:%.*]] = atomicrmw fmax ptr addrspace(1) [[PTR]], float [[VAL]] syncscope("one-as") seq_cst, align 4, !amdgpu.no.fine.grained.host.memory [[META0]], !amdgpu.no.remote.memory.access [[META0]], !amdgpu.ignore.denormal.mode [[META0]]
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; CHECK-NEXT: [[RMW_XOR:%.*]] = atomicrmw xor ptr addrspace(1) [[PTR]], i32 [[IVAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: [[RMW_FADD_VECTOR:%.*]] = atomicrmw fadd ptr addrspace(1) [[PTR]], <2 x half> [[VVAL]] syncscope("one-as") seq_cst, align 4, !amdgpu.no.fine.grained.host.memory [[META0]], !amdgpu.no.remote.memory.access [[META0]], !amdgpu.ignore.denormal.mode [[META0]]
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; CHECK-NEXT: [[RMW_FSUB_VECTOR:%.*]] = atomicrmw fsub ptr addrspace(1) [[PTR]], <2 x half> [[VVAL]] syncscope("one-as") seq_cst, align 4, !amdgpu.no.fine.grained.host.memory [[META0]], !amdgpu.no.remote.memory.access [[META0]], !amdgpu.ignore.denormal.mode [[META0]]
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; CHECK-NEXT: [[RMW_FMIN_VECTOR:%.*]] = atomicrmw fmin ptr addrspace(1) [[PTR]], <2 x half> [[VVAL]] syncscope("one-as") seq_cst, align 4, !amdgpu.no.fine.grained.host.memory [[META0]], !amdgpu.no.remote.memory.access [[META0]], !amdgpu.ignore.denormal.mode [[META0]]
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; CHECK-NEXT: [[RMW_FMAX_VECTOR:%.*]] = atomicrmw fmax ptr addrspace(1) [[PTR]], <2 x half> [[VVAL]] syncscope("one-as") seq_cst, align 4, !amdgpu.no.fine.grained.host.memory [[META0]], !amdgpu.no.remote.memory.access [[META0]], !amdgpu.ignore.denormal.mode [[META0]]
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; CHECK-NEXT: [[RMW_XCHG:%.*]] = atomicrmw xchg ptr addrspace(1) [[PTR]], float [[VAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: ret void
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;
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%rmw.fadd = atomicrmw fadd ptr addrspace(1) %ptr, float %val syncscope("one-as") seq_cst
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%rmw.fsub = atomicrmw fsub ptr addrspace(1) %ptr, float %val syncscope("one-as") seq_cst
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%rmw.fmin = atomicrmw fmin ptr addrspace(1) %ptr, float %val syncscope("one-as") seq_cst
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%rmw.fmax = atomicrmw fmax ptr addrspace(1) %ptr, float %val syncscope("one-as") seq_cst
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%rmw.xor = atomicrmw xor ptr addrspace(1) %ptr, i32 %ival syncscope("one-as") seq_cst
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%rmw.fadd.vector = atomicrmw fadd ptr addrspace(1) %ptr, <2 x half> %vval syncscope("one-as") seq_cst
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%rmw.fsub.vector = atomicrmw fsub ptr addrspace(1) %ptr, <2 x half> %vval syncscope("one-as") seq_cst
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%rmw.fmin.vector = atomicrmw fmin ptr addrspace(1) %ptr, <2 x half> %vval syncscope("one-as") seq_cst
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%rmw.fmax.vector = atomicrmw fmax ptr addrspace(1) %ptr, <2 x half> %vval syncscope("one-as") seq_cst
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; xchg doesn't need any metadata
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%rmw.xchg = atomicrmw xchg ptr addrspace(1) %ptr, float %val syncscope("one-as") seq_cst
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ret void
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}
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; Should just delete the effectless attribute if it exists
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define void @unsafe_fp_atomics_false(ptr addrspace(1) %ptr, float %val, i32 %ival, <2 x half> %vval) "amdgpu-unsafe-fp-atomics"="false" {
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; CHECK-LABEL: define void @unsafe_fp_atomics_false(
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; CHECK-SAME: ptr addrspace(1) [[PTR:%.*]], float [[VAL:%.*]], i32 [[IVAL:%.*]], <2 x half> [[VVAL:%.*]]) {
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; CHECK-NEXT: [[RMW_FADD:%.*]] = atomicrmw fadd ptr addrspace(1) [[PTR]], float [[VAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: [[RMW_FSUB:%.*]] = atomicrmw fsub ptr addrspace(1) [[PTR]], float [[VAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: [[RMW_FMIN:%.*]] = atomicrmw fmin ptr addrspace(1) [[PTR]], float [[VAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: [[RMW_FMAX:%.*]] = atomicrmw fmax ptr addrspace(1) [[PTR]], float [[VAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: [[RMW_XOR:%.*]] = atomicrmw xor ptr addrspace(1) [[PTR]], i32 [[IVAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: [[RMW_FADD_VECTOR:%.*]] = atomicrmw fadd ptr addrspace(1) [[PTR]], <2 x half> [[VVAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: [[RMW_FSUB_VECTOR:%.*]] = atomicrmw fsub ptr addrspace(1) [[PTR]], <2 x half> [[VVAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: [[RMW_FMIN_VECTOR:%.*]] = atomicrmw fmin ptr addrspace(1) [[PTR]], <2 x half> [[VVAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: [[RMW_FMAX_VECTOR:%.*]] = atomicrmw fmax ptr addrspace(1) [[PTR]], <2 x half> [[VVAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: [[RMW_XCHG:%.*]] = atomicrmw xchg ptr addrspace(1) [[PTR]], float [[VAL]] syncscope("one-as") seq_cst, align 4
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; CHECK-NEXT: ret void
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;
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%rmw.fadd = atomicrmw fadd ptr addrspace(1) %ptr, float %val syncscope("one-as") seq_cst
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%rmw.fsub = atomicrmw fsub ptr addrspace(1) %ptr, float %val syncscope("one-as") seq_cst
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%rmw.fmin = atomicrmw fmin ptr addrspace(1) %ptr, float %val syncscope("one-as") seq_cst
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%rmw.fmax = atomicrmw fmax ptr addrspace(1) %ptr, float %val syncscope("one-as") seq_cst
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%rmw.xor = atomicrmw xor ptr addrspace(1) %ptr, i32 %ival syncscope("one-as") seq_cst
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%rmw.fadd.vector = atomicrmw fadd ptr addrspace(1) %ptr, <2 x half> %vval syncscope("one-as") seq_cst
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%rmw.fsub.vector = atomicrmw fsub ptr addrspace(1) %ptr, <2 x half> %vval syncscope("one-as") seq_cst
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%rmw.fmin.vector = atomicrmw fmin ptr addrspace(1) %ptr, <2 x half> %vval syncscope("one-as") seq_cst
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%rmw.fmax.vector = atomicrmw fmax ptr addrspace(1) %ptr, <2 x half> %vval syncscope("one-as") seq_cst
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; xchg doesn't need any metadata
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%rmw.xchg = atomicrmw xchg ptr addrspace(1) %ptr, float %val syncscope("one-as") seq_cst
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ret void
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}
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;.
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; CHECK: attributes #[[ATTR0:[0-9]+]] = { "amdgpu-unsafe-fp-atomics"="true" }
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; CHECK: attributes #[[ATTR1:[0-9]+]] = { "amdgpu-unsafe-fp-atomics"="false" }
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;.
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; CHECK: [[META0]] = !{}
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;.

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