[fast-isel] Add X86FastIsel::FastLowerArguments to handle functions with 6 or
fewer scalar integer (i32 or i64) arguments. It completely eliminates the need
for SDISel for trivial functions.
Also, add the new llc -fast-isel-abort-args option, which is similar to
-fast-isel-abort option, but for formal argument lowering.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176052 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index a598ec4..1c92f8b 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -145,6 +145,10 @@
static cl::opt<bool>
EnableFastISelAbort("fast-isel-abort", cl::Hidden,
cl::desc("Enable abort calls when \"fast\" instruction fails"));
+static cl::opt<bool>
+EnableFastISelAbortArgs("fast-isel-abort-args", cl::Hidden,
+ cl::desc("Enable abort calls when \"fast\" instruction fails to "
+ "lower formal arguments"));
static cl::opt<bool>
UseMBPI("use-mbpi",
@@ -1048,6 +1052,12 @@
if (LLVMBB == &Fn.getEntryBlock()) {
// Lower any arguments needed in this block if this is the entry block.
if (!FastIS->LowerArguments()) {
+
+ if (EnableFastISelAbortArgs)
+ // The "fast" selector couldn't lower these arguments. For the
+ // purpose of debugging, just abort.
+ llvm_unreachable("FastISel didn't lower all arguments");
+
// Call target indepedent SDISel argument lowering code if the target
// specific routine is not successful.
LowerArguments(LLVMBB);