llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-backend-webassembly Author: None (llvmbot) <details> <summary>Changes</summary> Backport e5b2a06546eb20662156b8a59b77aca086301486 Requested by: @<!-- -->dschuff --- Full diff: https://github.com/llvm/llvm-project/pull/171184.diff 3 Files Affected: - (modified) llvm/lib/Target/WebAssembly/WebAssemblyExplicitLocals.cpp (+14) - (modified) llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp (+4) - (added) llvm/test/CodeGen/WebAssembly/fake-use.ll (+25) ``````````diff diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyExplicitLocals.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyExplicitLocals.cpp index e6486e247209b..5c3127e2d3dc6 100644 --- a/llvm/lib/Target/WebAssembly/WebAssemblyExplicitLocals.cpp +++ b/llvm/lib/Target/WebAssembly/WebAssemblyExplicitLocals.cpp @@ -216,6 +216,18 @@ static MachineInstr *findStartOfTree(MachineOperand &MO, return Def; } +// FAKE_USEs are no-ops, so remove them here so that the values used by them +// will be correctly dropped later. +static void removeFakeUses(MachineFunction &MF) { + SmallVector<MachineInstr *> ToDelete; + for (auto &MBB : MF) + for (auto &MI : MBB) + if (MI.isFakeUse()) + ToDelete.push_back(&MI); + for (auto *MI : ToDelete) + MI->eraseFromParent(); +} + bool WebAssemblyExplicitLocals::runOnMachineFunction(MachineFunction &MF) { LLVM_DEBUG(dbgs() << "********** Make Locals Explicit **********\n" "********** Function: " @@ -226,6 +238,8 @@ bool WebAssemblyExplicitLocals::runOnMachineFunction(MachineFunction &MF) { WebAssemblyFunctionInfo &MFI = *MF.getInfo<WebAssemblyFunctionInfo>(); const auto *TII = MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo(); + removeFakeUses(MF); + // Map non-stackified virtual registers to their local ids. DenseMap<unsigned, unsigned> Reg2Local; diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp index bc91c6424b63e..fd13ef9a1921d 100644 --- a/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp +++ b/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp @@ -866,6 +866,10 @@ bool WebAssemblyRegStackify::runOnMachineFunction(MachineFunction &MF) { if (Insert->isDebugValue()) continue; + // Ignore FAKE_USEs, which are no-ops and will be deleted later. + if (Insert->isFakeUse()) + continue; + // Iterate through the inputs in reverse order, since we'll be pulling // operands off the stack in LIFO order. CommutingState Commuting; diff --git a/llvm/test/CodeGen/WebAssembly/fake-use.ll b/llvm/test/CodeGen/WebAssembly/fake-use.ll new file mode 100644 index 0000000000000..a18ce33566df0 --- /dev/null +++ b/llvm/test/CodeGen/WebAssembly/fake-use.ll @@ -0,0 +1,25 @@ +; RUN: llc < %s | llvm-mc -triple=wasm32-unknown-unknown + +target triple = "wasm32-unknown-unknown" + +define void @fake_use() { + %t = call i32 @foo() + tail call void (...) @llvm.fake.use(i32 %t) + ret void +} + +; %t shouldn't be converted to TEE in RegStackify, because the FAKE_USE will be +; deleted in the beginning of ExplicitLocals. +define void @fake_use_no_tee() { + %t = call i32 @foo() + tail call void (...) @llvm.fake.use(i32 %t) + call void @use(i32 %t) + ret void +} + +declare i32 @foo() +declare void @use(i32 %t) +; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: readwrite) +declare void @llvm.fake.use(...) #0 + +attributes #0 = { mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: readwrite) } `````````` </details> https://github.com/llvm/llvm-project/pull/171184 _______________________________________________ llvm-branch-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
