From 400f75cb5ed39ab4f071f78f6a26beefbc8a46f0 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Thu, 3 Jun 2010 20:21:33 +0000
Subject: Fix SimplifyDemandedBits' AssertZext logic to demand all the bits. It
 needs to demand the high bits because it's asserting that they're zero.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105406 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/CodeGen/X86/promote-assert-zext.ll | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 test/CodeGen/X86/promote-assert-zext.ll

(limited to 'test/CodeGen/X86/promote-assert-zext.ll')

diff --git a/test/CodeGen/X86/promote-assert-zext.ll b/test/CodeGen/X86/promote-assert-zext.ll
new file mode 100644
index 0000000000..b582806c96
--- /dev/null
+++ b/test/CodeGen/X86/promote-assert-zext.ll
@@ -0,0 +1,22 @@
+; RUN: llc < %s | FileCheck %s
+; rdar://8051990
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+target triple = "x86_64-apple-darwin11"
+
+; ISel doesn't yet know how to eliminate this extra zero-extend. But until
+; it knows how to do so safely, it shouldn;t eliminate it.
+; CHECK: movzbl  (%rdi), %eax
+; CHECK: movzwl  %ax, %eax
+
+define i64 @_ZL5matchPKtPKhiR9MatchData(i8* %tmp13) nounwind {
+entry:
+  %tmp14 = load i8* %tmp13, align 1
+  %tmp17 = zext i8 %tmp14 to i16
+  br label %bb341
+
+bb341:
+  %tmp18 = add i16 %tmp17, -1
+  %tmp23 = sext i16 %tmp18 to i64
+  ret i64 %tmp23
+}
-- 
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