IR printing improvement for loop passes

Summary:
Loop-pass printing is somewhat deficient since it does not provide the
context around the loop (e.g. preheader). This context information becomes
pretty essential when analyzing transformations that move stuff out of the loop.

Extending printLoop to cover preheader and exit blocks (if any).

Reviewers: sanjoy, silvas, weimingz

Reviewed By: sanjoy

Subscribers: apilipenko, skatkov, llvm-commits

Differential Revision: https://reviews.llvm.org/D40246

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318878 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 67 insertions, 0 deletions

diff --git a/test/Other/loop-pass-printer.ll b/test/Other/loop-pass-printer.ll
new file mode 100644
index 00000000000..e5ad8bdb1f9
--- /dev/null
+++ b/test/Other/loop-pass-printer.ll
@@ -0,0 +1,67 @@
+; This test checks -print-after/before on loop passes
+; Besides of the loop itself it should be dumping loop pre-header and exits.
+;
+; RUN: opt < %s 2>&1 -disable-output \
+; RUN: 	   -loop-deletion -print-before=loop-deletion \
+; RUN:	   | FileCheck %s -check-prefix=DEL
+; RUN: opt < %s 2>&1 -disable-output \
+; RUN: 	   -loop-unroll -print-after=loop-unroll -filter-print-funcs=bar \
+; RUN:	   | FileCheck %s -check-prefix=BAR
+;
+
+; DEL:	    IR Dump Before
+; DEL-SAME: dead loops
+; DEL: 	    ; Preheader:
+; DEL-NEXT:  %idx = alloca i32, align 4
+; DEL:      ; Loop:
+; DEL-NEXT:  loop:
+; DEL:	     cont:
+; DEL:	    ; Exit blocks
+; DEL:	     done:
+; DEL:	    IR Dump Before
+; DEL-SAME: dead loops
+; DEL: 	    ; Preheader:
+; DEL-NEXT:  br label %loop
+; DEL:      ; Loop:
+; DEL-NEXT:  loop:
+; DEL:	    ; Exit blocks
+; DEL:	     end:
+
+; BAR:	    IR Dump After
+; BAR-SAME: Unroll
+; BAR: 	    ; Preheader:
+; BAR-NEXT:  br label %loop
+; BAR:      ; Loop:
+; BAR-NEXT:  loop:
+; BAR:	    ; Exit blocks
+; BAR:	     end:
+; BAR-NOT: IR Dump Before
+; BAR-NOT:  ; Loop
+
+define void @foo(){
+  %idx = alloca i32, align 4
+  store i32 0, i32* %idx, align 4
+  br label %loop
+
+loop:
+  %1 = load i32, i32* %idx, align 4
+  %2 = icmp slt i32 %1, 10
+  br i1 %2, label %cont, label %done
+
+cont:
+  %3 = load i32, i32* %idx, align 4
+  %4 = add nsw i32 %3, 1
+  store i32 %4, i32* %idx, align 4
+  br label %loop
+
+done:
+  ret void
+}
+
+define void @bar(){
+  br label %loop
+loop:
+  br i1 1, label %loop, label %end
+end:
+  ret void
+}