llvm-6502/test/Transforms/InstCombine/2012-08-28-udiv_ashl.ll
Nadav Rotem 9753f0b9b4 Teach InstCombine to canonicalize [SU]div+[AL]shl patterns.
For example:
  %1 = lshr i32 %x, 2
  %2 = udiv i32 %1, 100

rdar://12182093




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162743 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-28 10:01:43 +00:00

51 lines
1.1 KiB
LLVM

; RUN: opt -S -instcombine < %s | FileCheck %s
; rdar://12182093
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-S128"
target triple = "x86_64-apple-macosx10.8.0"
; CHECK: @udiv400
; CHECK: udiv i32 %x, 400
; CHECK: ret
define i32 @udiv400(i32 %x) {
entry:
%div = lshr i32 %x, 2
%div1 = udiv i32 %div, 100
ret i32 %div1
}
; CHECK: @sdiv400
; CHECK: sdiv i32 %x, 400
; CHECK: ret
define i32 @sdiv400(i32 %x) {
entry:
%div = ashr i32 %x, 2
%div1 = sdiv i32 %div, 100
ret i32 %div1
}
; CHECK: @udiv400_no
; CHECK: ashr
; CHECK: div
; CHECK: ret
define i32 @udiv400_no(i32 %x) {
entry:
%div = ashr i32 %x, 2
%div1 = udiv i32 %div, 100
ret i32 %div1
}
; CHECK: @sdiv400_yes
; CHECK: udiv i32 %x, 400
; CHECK: ret
define i32 @sdiv400_yes(i32 %x) {
entry:
%div = lshr i32 %x, 2
; The sign bits of both operands are zero (i.e. we can prove they are
; unsigned inputs), turn this into a udiv.
; Next, optimize this just like sdiv.
%div1 = sdiv i32 %div, 100
ret i32 %div1
}