[MachineOutliner] Outline both register save calls + no LR save calls together

Instead of treating the outlined functions for these as distinct frames, they
should be combined into one case. Neither allows for stack fixups, and both
generate the same frame. Thus, they ought to be considered one case.

This makes the code far easier to understand, for one thing. It also offers
some small code size improvements. It's fairly rare to see a class of outlined
functions that doesn't fall entirely into one variant (on CTMark anyway). It
does happen from time to time though.

This mostly offers some serious simplification.

Also update the test to show the added functionality.

llvm-svn: 348036

1 files changed, 26 insertions, 10 deletions

diff --git a/llvm/test/CodeGen/AArch64/machine-outliner-regsave.mir b/llvm/test/CodeGen/AArch64/machine-outliner-regsave.mir
index 6d00bd39cde..d05cbddbb32 100644
--- a/llvm/test/CodeGen/AArch64/machine-outliner-regsave.mir
+++ b/llvm/test/CodeGen/AArch64/machine-outliner-regsave.mir
@@ -2,8 +2,8 @@
 # RUN: -run-pass=machine-outliner -verify-machineinstrs %s -o - | FileCheck %s
 # Check that we save LR to a callee-saved register when possible.
 # foo() should use a callee-saved register. However, bar() should not.
---- |  
-  
+--- |
+
   define void @foo() #0 {
     ret void
   }
@@ -17,33 +17,40 @@
 ---
 # Make sure that when we outline and a register is available, we
 # use it to save + restore LR instead of SP.
+# Also make sure that we can call functions that require no save as the same
+# outlined function.
 # CHECK: name:            foo
-# CHECK-DAG: bb.0
+# CHECK-DAG: bb.1
 # CHECK-DAG: $x[[REG:[0-9]+]] = ORRXrs $xzr, $lr, 0
 # CHECK-NEXT: BL
 # CHECK-NEXT: $lr = ORRXrs $xzr, $x[[REG]], 0
-# CHECK-DAG: bb.1
+# CHECK-DAG: bb.2
 # CHECK-DAG: $x[[REG]] = ORRXrs $xzr, $lr, 0
 # CHECK-NEXT: BL
 # CHECK-NEXT: $lr = ORRXrs $xzr, $x[[REG]], 0
-# CHECK-DAG: bb.2
+# CHECK-DAG: bb.3
 # CHECK-DAG: $x[[REG]] = ORRXrs $xzr, $lr, 0
 # CHECK-NEXT: BL
 # CHECK-NEXT: $lr = ORRXrs $xzr, $x[[REG]], 0
+# CHECK-DAG: bb.4
+# CHECK-NOT: $x[[REG]] = ORRXrs $xzr, $lr, 0
+# CHECK-DAG: BL
 name:            foo
 tracksRegLiveness: true
-fixedStack:      
+fixedStack:
 body:             |
   bb.0:
-    liveins: $lr, $w9
     $x25 = ORRXri $xzr, 1
+    $lr = ORRXri $xzr, 1
+  bb.1:
+    liveins: $lr, $w9
     $w9 = ORRWri $wzr, 1
     $w9 = ORRWri $wzr, 1
     $w9 = ORRWri $wzr, 1
     $w9 = ORRWri $wzr, 1
     $w9 = ORRWri $wzr, 1
     $w9 = ORRWri $wzr, 2
-  bb.1:
+  bb.2:
     liveins: $lr, $w9
     $w9 = ORRWri $wzr, 1
     $w9 = ORRWri $wzr, 1
@@ -51,7 +58,15 @@ body:             |
     $w9 = ORRWri $wzr, 1
     $w9 = ORRWri $wzr, 1
     $w9 = ORRWri $wzr, 2
-  bb.2:
+  bb.3:
+    liveins: $lr, $w9
+    $w9 = ORRWri $wzr, 1
+    $w9 = ORRWri $wzr, 1
+    $w9 = ORRWri $wzr, 1
+    $w9 = ORRWri $wzr, 1
+    $w9 = ORRWri $wzr, 1
+    $w9 = ORRWri $wzr, 2
+  bb.4:
     liveins: $lr, $w9
     $w9 = ORRWri $wzr, 1
     $w9 = ORRWri $wzr, 1
@@ -59,6 +74,8 @@ body:             |
     $w9 = ORRWri $wzr, 1
     $w9 = ORRWri $wzr, 1
     $w9 = ORRWri $wzr, 2
+  bb.5:
+    liveins: $w9
     RET undef $lr
 
 ...
@@ -109,4 +126,3 @@ body:             |
   bb.3:
     liveins: $lr, $x0, $x1, $x2, $x3, $x4, $x5, $x6, $x7, $x8, $x9, $x10, $x11, $x12, $x13, $x14, $x15, $x19, $x20, $x21, $x22, $x23, $x20, $x21, $x22, $x23, $x24, $x25, $x26, $x27, $x28
     RET undef $lr
-