From 4162eced737c83a193247f48dd1c608e82fa2a35 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Fri, 21 Oct 2011 08:01:56 +0000
Subject: [PATCH] Add a very basic test for MachineBlockPlacement. This is
 essentially the canonical example I used when developing it, and is one of
 the primary motivating real-world use cases for __builtin_expect (when
 burried under a macro).

I'm working on more test cases here, but I'm trying to make sure both
that the pass is doing the right thing with the test cases and that they
aren't too brittle to changes elsewhere in the code generation pipeline.

Feedback and/or suggestions on how to test this are very welcome.
Especially feedback on whether testing the block comments is a good
strategy; I couldn't find any good examples to steal from but all the
other ideas I had were a lot uglier or more fragile.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142644 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/CodeGen/X86/block-placement.ll | 75 +++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 test/CodeGen/X86/block-placement.ll

diff --git a/test/CodeGen/X86/block-placement.ll b/test/CodeGen/X86/block-placement.ll
new file mode 100644
index 00000000000..c7ab6ef8218
--- /dev/null
+++ b/test/CodeGen/X86/block-placement.ll
@@ -0,0 +1,75 @@
+; RUN: llc -march=x86 -enable-block-placement < %s | FileCheck %s
+
+declare void @error(i32 %i, i32 %a, i32 %b)
+
+define i32 @test1(i32 %i, i32* %a, i32 %b) {
+; Test a chain of ifs, where the block guarded by the if is error handling code
+; that is not expected to run.
+; CHECK: test1:
+; CHECK: %entry
+; CHECK: %else1
+; CHECK: %else2
+; CHECK: %else3
+; CHECK: %else4
+; CHECK: %exit
+; CHECK: %then1
+; CHECK: %then2
+; CHECK: %then3
+; CHECK: %then4
+; CHECK: %then5
+
+entry:
+  %gep1 = getelementptr i32* %a, i32 1
+  %val1 = load i32* %gep1
+  %cond1 = icmp ugt i32 %val1, 1
+  br i1 %cond1, label %then1, label %else1, !prof !0
+
+then1:
+  call void @error(i32 %i, i32 1, i32 %b)
+  br label %else1
+
+else1:
+  %gep2 = getelementptr i32* %a, i32 2
+  %val2 = load i32* %gep2
+  %cond2 = icmp ugt i32 %val2, 2
+  br i1 %cond2, label %then2, label %else2, !prof !0
+
+then2:
+  call void @error(i32 %i, i32 1, i32 %b)
+  br label %else2
+
+else2:
+  %gep3 = getelementptr i32* %a, i32 3
+  %val3 = load i32* %gep3
+  %cond3 = icmp ugt i32 %val3, 3
+  br i1 %cond3, label %then3, label %else3, !prof !0
+
+then3:
+  call void @error(i32 %i, i32 1, i32 %b)
+  br label %else3
+
+else3:
+  %gep4 = getelementptr i32* %a, i32 4
+  %val4 = load i32* %gep4
+  %cond4 = icmp ugt i32 %val4, 4
+  br i1 %cond4, label %then4, label %else4, !prof !0
+
+then4:
+  call void @error(i32 %i, i32 1, i32 %b)
+  br label %else4
+
+else4:
+  %gep5 = getelementptr i32* %a, i32 3
+  %val5 = load i32* %gep5
+  %cond5 = icmp ugt i32 %val5, 3
+  br i1 %cond5, label %then5, label %exit, !prof !0
+
+then5:
+  call void @error(i32 %i, i32 1, i32 %b)
+  br label %exit
+
+exit:
+  ret i32 %b
+}
+
+!0 = metadata !{metadata !"branch_weights", i32 4, i32 64}
-- 
2.34.1