[FastISel] Add a diagnostic to warm on fallback.

This is consistent with what we do for GlobalISel. That way, it is easy
to see whether or not FastISel is able to fully select a function.
At some point we may want to switch that to an optimization remark.

llvm-svn: 294970

1 files changed, 14 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/fast-isel-abort-warm.ll b/llvm/test/CodeGen/X86/fast-isel-abort-warm.ll
new file mode 100644
index 00000000000..3caa91b11ec
--- /dev/null
+++ b/llvm/test/CodeGen/X86/fast-isel-abort-warm.ll
@@ -0,0 +1,14 @@
+; RUN: llc -fast-isel -o - %s -fast-isel-report-on-fallback 2>&1 | FileCheck %s
+; Make sure FastISel report a warming when we asked it to do so.
+; Note: This test needs to use whatever is not supported by FastISel.
+;       Thus, this test may fail because inline asm gets supported in FastISel.
+;       To fix this, use something else that's not supported (e.g., weird types).
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx"
+
+; CHECK: warning: Instruction selection used fallback path for foo
+define void @foo(){
+entry:
+  call void asm sideeffect "nop", "~{dirflag},~{fpsr},~{flags}"()
+  ret void
+}