From 05cd88656135255b545d24adb51c2ba1b5c8b99e Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Mon, 23 May 2011 00:21:50 +0000 Subject: Transform any logical shift of a power of two into an exact/NUW shift when in a known-non-zero context. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131887 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/Transforms/InstCombine/shift.ll | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'test') diff --git a/test/Transforms/InstCombine/shift.ll b/test/Transforms/InstCombine/shift.ll index bded68ac47..d9ac9cbfe9 100644 --- a/test/Transforms/InstCombine/shift.ll +++ b/test/Transforms/InstCombine/shift.ll @@ -506,3 +506,24 @@ define i32 @test41(i32 %a, i32 %b) nounwind { ; CHECK-NEXT: shl i32 8, %b ; CHECK-NEXT: ret i32 } + +define i32 @test42(i32 %a, i32 %b) nounwind { + %div = lshr i32 4096, %b ; must be exact otherwise we'd divide by zero + %div2 = udiv i32 %a, %div + ret i32 %div2 +; CHECK: @test42 +; CHECK-NEXT: lshr exact i32 4096, %b +} + +define i32 @test43(i32 %a, i32 %b) nounwind { + %div = shl i32 4096, %b ; must be exact otherwise we'd divide by zero + %div2 = udiv i32 %a, %div + ret i32 %div2 +; CHECK: @test43 +; CHECK-NEXT: add i32 %b, 12 +; CHECK-NEXT: lshr +; CHECK-NEXT: ret +} + + + -- cgit v1.2.3-18-g5258