From 28dc98f7521933872b93156e3ebf5c9f8327b2b3 Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Wed, 17 Dec 2008 03:35:17 +0000
Subject: Fix for PR3225: disable a broken optimization in
 DAGTypeLegalizer::ExpandShiftWithKnownAmountBit.

In terms of restoring the optimization, the best fix here isn't
obvious... any ideas?



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61119 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/CodeGen/X86/2008-12-16-BadShift.ll | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 test/CodeGen/X86/2008-12-16-BadShift.ll

(limited to 'test/CodeGen/X86/2008-12-16-BadShift.ll')

diff --git a/test/CodeGen/X86/2008-12-16-BadShift.ll b/test/CodeGen/X86/2008-12-16-BadShift.ll
new file mode 100644
index 0000000..46b7018
--- /dev/null
+++ b/test/CodeGen/X86/2008-12-16-BadShift.ll
@@ -0,0 +1,19 @@
+; RUN: llvm-as < %s | llc | not grep shrl
+; Note: this test is really trying to make sure that the shift
+; returns the right result; shrl is most likely wrong,
+; but if CodeGen starts legitimately using an shrl here,
+; please adjust the test appropriately.
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
+target triple = "i386-pc-linux-gnu"
+@.str = internal constant [6 x i8] c"%lld\0A\00"		; <[6 x i8]*> [#uses=1]
+
+define i64 @mebbe_shift(i32 %xx, i32 %test) nounwind {
+entry:
+	%conv = zext i32 %xx to i64		; <i64> [#uses=1]
+	%tobool = icmp ne i32 %test, 0		; <i1> [#uses=1]
+	%shl = select i1 %tobool, i64 3, i64 0		; <i64> [#uses=1]
+	%x.0 = shl i64 %conv, %shl		; <i64> [#uses=1]
+	ret i64 %x.0
+}
+
-- 
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