From 8979e5f3725c05bd7120890e39399213fd08f83e Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Fri, 2 Mar 2012 15:34:43 +0000
Subject: LVI: Recognize the form instcombine canonicalizes range checks into
 when forming constant ranges.

This could probably be made a lot smarter, but this is a common case and doesn't require LVI to scan a lot
of code. With this change CVP can optimize away the "shift == 0" case in Hashing.h that only gets hit when
"shift" is in a range not containing 0.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151919 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../Transforms/CorrelatedValuePropagation/range.ll | 43 ++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 test/Transforms/CorrelatedValuePropagation/range.ll

(limited to 'test/Transforms/CorrelatedValuePropagation')

diff --git a/test/Transforms/CorrelatedValuePropagation/range.ll b/test/Transforms/CorrelatedValuePropagation/range.ll
new file mode 100644
index 0000000000..9b70ed200e
--- /dev/null
+++ b/test/Transforms/CorrelatedValuePropagation/range.ll
@@ -0,0 +1,43 @@
+; RUN: opt -correlated-propagation -S < %s | FileCheck %s
+
+declare i32 @foo()
+
+define i32 @test1(i32 %a) nounwind {
+  %a.off = add i32 %a, -8
+  %cmp = icmp ult i32 %a.off, 8
+  br i1 %cmp, label %then, label %else
+
+then:
+  %dead = icmp eq i32 %a, 7
+  br i1 %dead, label %end, label %else
+
+else:
+  ret i32 1
+
+end:
+  ret i32 2
+
+; CHECK: @test1
+; CHECK: then:
+; CHECK-NEXT: br i1 false, label %end, label %else
+}
+
+define i32 @test2(i32 %a) nounwind {
+  %a.off = add i32 %a, -8
+  %cmp = icmp ult i32 %a.off, 8
+  br i1 %cmp, label %then, label %else
+
+then:
+  %dead = icmp ugt i32 %a, 15
+  br i1 %dead, label %end, label %else
+
+else:
+  ret i32 1
+
+end:
+  ret i32 2
+
+; CHECK: @test2
+; CHECK: then:
+; CHECK-NEXT: br i1 false, label %end, label %else
+}
-- 
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