2011-05-28-swapmulsub.ll   [plain text]

; ModuleID = 'test1.c'
; RUN: opt -S -instcombine < %s | FileCheck %s
target triple = "x86_64-apple-macosx10.6.6"

define zeroext i16 @foo1(i32 %on_off) nounwind uwtable ssp {
entry:
  %on_off.addr = alloca i32, align 4
  %a = alloca i32, align 4
  store i32 %on_off, i32* %on_off.addr, align 4
  %tmp = load i32* %on_off.addr, align 4
  %sub = sub i32 1, %tmp
; CHECK-NOT: mul i32
  %mul = mul i32 %sub, -2
; CHECK: shl
; CHECK-NEXT: add
  store i32 %mul, i32* %a, align 4
  %tmp1 = load i32* %a, align 4
  %conv = trunc i32 %tmp1 to i16
  ret i16 %conv
}

define zeroext i16 @foo2(i32 %on_off, i32 %q) nounwind uwtable ssp {
entry:
  %on_off.addr = alloca i32, align 4
  %q.addr = alloca i32, align 4
  %a = alloca i32, align 4
  store i32 %on_off, i32* %on_off.addr, align 4
  store i32 %q, i32* %q.addr, align 4
  %tmp = load i32* %q.addr, align 4
  %tmp1 = load i32* %on_off.addr, align 4
  %sub = sub i32 %tmp, %tmp1
; CHECK-NOT: mul i32
  %mul = mul i32 %sub, -4
; CHECK: sub i32
; CHECK-NEXT: shl
  store i32 %mul, i32* %a, align 4
  %tmp2 = load i32* %a, align 4
  %conv = trunc i32 %tmp2 to i16
  ret i16 %conv
}

define zeroext i16 @foo3(i32 %on_off) nounwind uwtable ssp {
entry:
  %on_off.addr = alloca i32, align 4
  %a = alloca i32, align 4
  store i32 %on_off, i32* %on_off.addr, align 4
  %tmp = load i32* %on_off.addr, align 4
  %sub = sub i32 7, %tmp
; CHECK-NOT: mul i32
  %mul = mul i32 %sub, -4
; CHECK: shl
; CHECK-NEXT: add
  store i32 %mul, i32* %a, align 4
  %tmp1 = load i32* %a, align 4
  %conv = trunc i32 %tmp1 to i16
  ret i16 %conv
}