From 9d32f60a6f7dbd8e83187481cd2ae0a2f3e726ce Mon Sep 17 00:00:00 2001
From: Duncan Sands <baldrick@free.fr>
Date: Thu, 20 Jan 2011 13:21:55 +0000
Subject: At -O123 the early-cse pass is run before instcombine has run. 
 According to my auto-simplier the transform most missed by early-cse is (zext
 X) != 0 -> X != 0. This patch adds this transform and some related logic to
 InstructionSimplify and removes some of the logic from instcombine
 (unfortunately not all because there are several situations in which
 instcombine can improve things by making new instructions, whereas
 instsimplify is not allowed to do this).  At -O2 this often results in more
 than 15% more simplifications by early-cse, and results in hundreds of lines
 of bitcode being eliminated from the testsuite.  I did see some small
 negative effects in the testsuite, for example a few additional instructions
 in three programs.  One program, 483.xalancbmk, got an additional 35
 instructions, which seems to be due to a function getting an additional
 instruction and then being inlined all over the place.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123911 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/Transforms/InstSimplify/2011-01-18-Compare.ll | 45 ++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 test/Transforms/InstSimplify/2011-01-18-Compare.ll

(limited to 'test/Transforms/InstSimplify')

diff --git a/test/Transforms/InstSimplify/2011-01-18-Compare.ll b/test/Transforms/InstSimplify/2011-01-18-Compare.ll
new file mode 100644
index 0000000000..127957942b
--- /dev/null
+++ b/test/Transforms/InstSimplify/2011-01-18-Compare.ll
@@ -0,0 +1,45 @@
+; RUN: opt < %s -instsimplify -S | FileCheck %s
+target datalayout = "p:32:32"
+
+define i1 @ptrtoint() {
+; CHECK: @ptrtoint
+  %a = alloca i8
+  %tmp = ptrtoint i8* %a to i32
+  %r = icmp eq i32 %tmp, 0
+  ret i1 %r
+; CHECK: ret i1 false
+}
+
+define i1 @zext(i32 %x) {
+; CHECK: @zext
+  %e1 = zext i32 %x to i64
+  %e2 = zext i32 %x to i64
+  %r = icmp eq i64 %e1, %e2
+  ret i1 %r
+; CHECK: ret i1 true
+}
+
+define i1 @zext2(i1 %x) {
+; CHECK: @zext2
+  %e = zext i1 %x to i32
+  %c = icmp ne i32 %e, 0
+  ret i1 %c
+; CHECK: ret i1 %x
+}
+
+define i1 @sext(i32 %x) {
+; CHECK: @sext
+  %e1 = sext i32 %x to i64
+  %e2 = sext i32 %x to i64
+  %r = icmp eq i64 %e1, %e2
+  ret i1 %r
+; CHECK: ret i1 true
+}
+
+define i1 @sext2(i1 %x) {
+; CHECK: @sext2
+  %e = sext i1 %x to i32
+  %c = icmp ne i32 %e, 0
+  ret i1 %c
+; CHECK: ret i1 %x
+}
-- 
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