From 0415b1810bbf93f434f1c561e172bf24c1cb37dc Mon Sep 17 00:00:00 2001
From: Tim Northover <tnorthover@apple.com>
Date: Wed, 4 Sep 2013 11:57:17 +0000
Subject: InstCombine: allow unmasked icmps to be combined with logical ops

"(icmp op i8 A, B)" is equivalent to "(icmp op i8 (A & 0xff), B)" as a
degenerate case. Allowing this as a "masked" comparison when analysing "(icmp)
&/| (icmp)" allows us to combine them in more cases.

rdar://problem/7625728

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189931 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/Transforms/InstCombine/icmp-logical.ll | 30 +++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

(limited to 'test/Transforms/InstCombine/icmp-logical.ll')

diff --git a/test/Transforms/InstCombine/icmp-logical.ll b/test/Transforms/InstCombine/icmp-logical.ll
index c0c5a61ef0..d5d8cbc8c2 100644
--- a/test/Transforms/InstCombine/icmp-logical.ll
+++ b/test/Transforms/InstCombine/icmp-logical.ll
@@ -120,3 +120,33 @@ define i1 @masked_or_allzeroes_notoptimised(i32 %A) {
   ret i1 %res
 }
 
+define i1 @nomask_lhs(i32 %in) {
+; CHECK-LABEL: @nomask_lhs
+; CHECK: [[MASK:%.*]] = and i32 %in, 1
+; CHECK: icmp eq i32 [[MASK]], 0
+; CHECK-NOT: icmp
+; CHECK: ret i1
+  %tst1 = icmp eq i32 %in, 0
+
+  %masked = and i32 %in, 1
+  %tst2 = icmp eq i32 %masked, 0
+
+  %val = or i1 %tst1, %tst2
+  ret i1 %val
+}
+
+
+define i1 @nomask_rhs(i32 %in) {
+; CHECK-LABEL: @nomask_rhs
+; CHECK: [[MASK:%.*]] = and i32 %in, 1
+; CHECK: icmp eq i32 [[MASK]], 0
+; CHECK-NOT: icmp
+; CHECK: ret i1
+  %masked = and i32 %in, 1
+  %tst1 = icmp eq i32 %masked, 0
+
+  %tst2 = icmp eq i32 %in, 0
+
+  %val = or i1 %tst1, %tst2
+  ret i1 %val
+}
-- 
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