From 1c10b8de46ce8e39178eeded4786b1e53722f099 Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Thu, 17 Mar 2011 20:39:14 +0000
Subject: BuildUDIV: If the divisor is even we can simplify the fixup of the
 multiplied value by introducing an early shift.

This allows us to compile "unsigned foo(unsigned x) { return x/28; }" into
	shrl	$2, %edi
	imulq	$613566757, %rdi, %rax
	shrq	$32, %rax
	ret

instead of
	movl    %edi, %eax
	imulq   $613566757, %rax, %rcx
	shrq    $32, %rcx
	subl    %ecx, %eax
	shrl    %eax
	addl    %ecx, %eax
	shrl    $4, %eax

on x86_64

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127829 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/CodeGen/X86/divide-by-constant.ll | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'test')

diff --git a/test/CodeGen/X86/divide-by-constant.ll b/test/CodeGen/X86/divide-by-constant.ll
index fe335b9369..08e3272a37 100644
--- a/test/CodeGen/X86/divide-by-constant.ll
+++ b/test/CodeGen/X86/divide-by-constant.ll
@@ -60,3 +60,14 @@ entry:
 ; CHECK: shrl	$31, %ecx
 ; CHECK: sarl	$18, %eax
 }
+
+define i32 @test7(i32 %x) nounwind {
+  %div = udiv i32 %x, 28
+  ret i32 %div
+; CHECK: test7:
+; CHECK: shrl $2
+; CHECK: movl $613566757
+; CHECK: mull
+; CHECK-NOT: shrl
+; CHECK: ret
+}
-- 
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