[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.

llvm-svn: 176052

1 files changed, 25 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/fast-isel-args.ll b/llvm/test/CodeGen/X86/fast-isel-args.ll
new file mode 100644
index 00000000000..ab42f6448d4
--- /dev/null
+++ b/llvm/test/CodeGen/X86/fast-isel-args.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s -fast-isel -fast-isel-abort -fast-isel-abort-args -verify-machineinstrs -mtriple=x86_64-apple-darwin10
+
+; Just make sure these don't abort when lowering the arguments.
+define i32 @t1(i32 %a, i32 %b, i32 %c) {
+entry:
+  %add = add nsw i32 %b, %a
+  %add1 = add nsw i32 %add, %c
+  ret i32 %add1
+}
+
+define i64 @t2(i64 %a, i64 %b, i64 %c) {
+entry:
+  %add = add nsw i64 %b, %a
+  %add1 = add nsw i64 %add, %c
+  ret i64 %add1
+}
+
+define i64 @t3(i32 %a, i64 %b, i32 %c) #2 {
+entry:
+  %conv = sext i32 %a to i64
+  %add = add nsw i64 %conv, %b
+  %conv1 = sext i32 %c to i64
+  %add2 = add nsw i64 %add, %conv1
+  ret i64 %add2
+}