DebugInfo: Don't lose unreferenced non-trivial by-value parameters

A FastISel optimization was causing us to emit no information for such
parameters & when they go missing we end up emitting a different
function type. By avoiding that shortcut we not only get types correct
(very important) but also location information (handy) - even if it's
only live at the start of a function & may be clobbered later.

Reviewed/discussion by Evan Cheng & Dan Gohman.

llvm-svn: 184604

1 files changed, 0 insertions, 2 deletions

diff --git a/llvm/lib/Target/X86/X86FastISel.cpp b/llvm/lib/Target/X86/X86FastISel.cpp
index 295a5771554..669108f2563 100644
--- a/llvm/lib/Target/X86/X86FastISel.cpp
+++ b/llvm/lib/Target/X86/X86FastISel.cpp
@@ -1732,8 +1732,6 @@ bool X86FastISel::FastLowerArguments() {
   const TargetRegisterClass *RC64 = TLI.getRegClassFor(MVT::i64);
   for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
        I != E; ++I, ++Idx) {
-    if (I->use_empty())
-      continue;
     bool is32Bit = TLI.getValueType(I->getType()) == MVT::i32;
     const TargetRegisterClass *RC = is32Bit ? RC32 : RC64;
     unsigned SrcReg = is32Bit ? GPR32ArgRegs[Idx] : GPR64ArgRegs[Idx];