diff --git a/llvm/lib/Target/BPF/BPFMIPeephole.cpp b/llvm/lib/Target/BPF/BPFMIPeephole.cpp --- a/llvm/lib/Target/BPF/BPFMIPeephole.cpp +++ b/llvm/lib/Target/BPF/BPFMIPeephole.cpp @@ -475,6 +475,9 @@ if (MI.getOpcode() == BPF::SRL_ri && MI.getOperand(2).getImm() == 32) { SrcReg = MI.getOperand(1).getReg(); + if (!MRI->hasOneNonDBGUse(SrcReg)) + continue; + MI2 = MRI->getVRegDef(SrcReg); DstReg = MI.getOperand(0).getReg(); diff --git a/llvm/test/CodeGen/BPF/remove_truncate_8.ll b/llvm/test/CodeGen/BPF/remove_truncate_8.ll new file mode 100644 --- /dev/null +++ b/llvm/test/CodeGen/BPF/remove_truncate_8.ll @@ -0,0 +1,41 @@ +; RUN: llc < %s -march=bpf -verify-machineinstrs | FileCheck %s +; Source Code: +; struct loc_prog { +; unsigned int ip; +; int len; +; }; +; int exec_prog(struct loc_prog *prog) { +; if (prog->ip < prog->len) { +; int x = prog->ip; +; if (x < 3) +; prog->ip += 2; +; } +; return 3; +; } +; Compilation flag: +; clang -target bpf -O2 -S -emit-llvm t.c + +%struct.loc_prog = type { i32, i32 } + +; Function Attrs: nofree norecurse nounwind willreturn +define dso_local i32 @exec_prog(%struct.loc_prog* nocapture %prog) local_unnamed_addr { +entry: + %ip = getelementptr inbounds %struct.loc_prog, %struct.loc_prog* %prog, i64 0, i32 0 + %0 = load i32, i32* %ip, align 4 + %len = getelementptr inbounds %struct.loc_prog, %struct.loc_prog* %prog, i64 0, i32 1 + %1 = load i32, i32* %len, align 4 + %cmp = icmp ult i32 %0, %1 + %cmp2 = icmp slt i32 %0, 3 + %or.cond = and i1 %cmp2, %cmp +; CHECK: r{{[0-9]+}} <<= 32 +; CHECK: r{{[0-9]+}} s>>= 32 + br i1 %or.cond, label %if.then3, label %if.end5 + +if.then3: ; preds = %entry + %add = add nsw i32 %0, 2 + store i32 %add, i32* %ip, align 4 + br label %if.end5 + +if.end5: ; preds = %if.then3, %entry + ret i32 3 +}