diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyExplicitLocals.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyExplicitLocals.cpp index 2662241ef8499..e6486e247209b 100644 --- a/llvm/lib/Target/WebAssembly/WebAssemblyExplicitLocals.cpp +++ b/llvm/lib/Target/WebAssembly/WebAssemblyExplicitLocals.cpp @@ -256,9 +256,17 @@ bool WebAssemblyExplicitLocals::runOnMachineFunction(MachineFunction &MF) { // Precompute the set of registers that are unused, so that we can insert // drops to their defs. + // And unstackify any stackified registers that don't have any uses, so that + // they can be dropped later. This can happen when transformations after + // RegStackify remove instructions using stackified registers. BitVector UseEmpty(MRI.getNumVirtRegs()); - for (unsigned I = 0, E = MRI.getNumVirtRegs(); I < E; ++I) - UseEmpty[I] = MRI.use_empty(Register::index2VirtReg(I)); + for (unsigned I = 0, E = MRI.getNumVirtRegs(); I < E; ++I) { + Register Reg = Register::index2VirtReg(I); + if (MRI.use_empty(Reg)) { + UseEmpty[I] = true; + MFI.unstackifyVReg(Reg); + } + } // Visit each instruction in the function. for (MachineBasicBlock &MBB : MF) { diff --git a/llvm/test/CodeGen/WebAssembly/removed-terminator.ll b/llvm/test/CodeGen/WebAssembly/removed-terminator.ll new file mode 100644 index 0000000000000..188f6f67eee8b --- /dev/null +++ b/llvm/test/CodeGen/WebAssembly/removed-terminator.ll @@ -0,0 +1,26 @@ +; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5 +; RUN: llc -O0 -verify-machineinstrs < %s | FileCheck %s + +target triple = "wasm32-unknown-unknown" + +define void @test(i1 %x) { +; CHECK-LABEL: test: +; CHECK: .functype test (i32) -> () +; CHECK-NEXT: # %bb.0: +; CHECK-NEXT: local.get 0 +; CHECK-NEXT: i32.const -1 +; CHECK-NEXT: i32.xor +; CHECK-NEXT: i32.const 1 +; CHECK-NEXT: i32.and +; CHECK-NEXT: drop +; CHECK-NEXT: # %bb.1: # %exit +; CHECK-NEXT: return + %y = xor i1 %x, true + ; This br_if's operand (%y) is stackified in RegStackify. But this terminator + ; will be removed in CFGSort after that. We need to make sure we unstackify %y + ; so that it can be dropped in ExplicitLocals. + br i1 %y, label %exit, label %exit + +exit: + ret void +}