minjang

/*
  This is a version (aka dlmalloc) of malloc/free/realloc written by
  Doug Lea and released to the public domain, as explained at
  http://creativecommons.org/publicdomain/zero/1.0/ Send questions,
  comments, complaints, performance data, etc to dl@cs.oswego.edu

* Version 2.8.6 Wed Aug 29 06:57:58 2012  Doug Lea
   Note: There may be an updated version of this malloc obtainable at
           ftp://gee.cs.oswego.edu/pub/misc/malloc.c
         Check before installing!

minjang

define i32 @_Z4testv() #0 {
entry:
  %a = call i32 @get()
  %b = call i32 @get()
  %b = call i32 @process(i32 %a, i32 %b)
  ret i32 %b
}

minjang

%a = call i32 @get()
%b = call i32 @get()
%xor = xor i32 %b, %a

%xor1 = xor i32 %a, %xor
; => %xor1 = %a ^ %xor
; => %xor1 = %a ^ (%b ^ %a)       ; a ^ (b ^ a) = b ^ 0
; => %xor1 = %b ^ 0               ; b ^ 0 = b
; => %xor1 = %b                   ; 이후 %xor1 사용처를 모두 %b로 바꿈
; => %xor1 삭제

minjang

define i32 @_Z4testv() #0 {
entry:
  %call = call i32 @_Z3getv()        ; a = get();
  %call1 = call i32 @_Z3getv()       ; b = get();
                                     ; temp_swap(a, b)는 사라짐
  %xor.i = xor i32 %call1, %call     ; xor_swap(a, b)가 xor_swap(b, a)로 바뀜
  %xor1.i = xor i32 %call, %xor.i
  %xor2.i = xor i32 %xor.i, %xor1.i
  %call2 = call i32 @_Z7processii(i32 %xor2.i, i32 %xor1.i)
  ret i32 %call2

minjang

define linkonce_odr void @void temp_swap<int>(int&, int&)(i32* %a, i32* %b) #2 {
entry:                             ; %0
  %0 = load i32, i32* %a, align 4  ; W  %1
  %1 = load i32, i32* %b, align 4  ; |  W
  store i32 %1, i32* %a, align 4   ; R  |
  store i32 %0, i32* %b, align 4   ;    R
  ret void
}

define linkonce_odr void @void xor_swap<int>(int&, int&)(i32* %a, i32* %b) #2 {

minjang

define i32 @_Z4testv() #0 {
entry:
  %a = alloca i32, align 4
  %b = alloca i32, align 4
  %call = call i32 @_Z3getv()             ; int a = get();
  store i32 %call, i32* %a, align 4
  %call1 = call i32 @_Z3getv()            ; int b = get();
  store i32 %call1, i32* %b, align 4
  %0 = load i32, i32* %a, align 4         ; temp_swap(a, b);
  %1 = load i32, i32* %b, align 4

minjang

$ ./opt -O3 -debug-pass=Structure -o swap.opt.bc swap.bc
Pass Arguments:  -tti -tbaa -scoped-noalias -assumption-cache-tracker -targetlibinfo -verify -simplifycfg -domtree -sroa -early-cse -basicaa -aa -memdep -memoryssa -gvn-hoist -lower-expect
Target Transform Information
Type-Based Alias Analysis
Scoped NoAlias Alias Analysis
Assumption Cache Tracker
Target Library Information
  FunctionPass Manager
    Module Verifier
    Simplify the CFG

minjang

define linkonce_odr void @void temp_swap<int>(int&, int&)(i32* %a, i32* %b) #2 {
entry:                             ; %0
  %0 = load i32, i32* %a, align 4  ; W  %1
  %1 = load i32, i32* %b, align 4  ; |  W
  store i32 %1, i32* %a, align 4   ; R  |
  store i32 %0, i32* %b, align 4   ;    R
  ret void
}

define linkonce_odr void @void xor_swap<int>(int&, int&)(i32* %a, i32* %b) #2 {

minjang

; ModuleID = 'swap.bc'
source_filename = "swap.cpp"
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.12.0"

; Function Attrs: ssp uwtable
define i32 @_Z4testv() #0 {
entry:
  %a = alloca i32, align 4
  %b = alloca i32, align 4

minjang

bool NStrideDetector::IsMergable(int64_t ea, int32_t /*size*/, const TRAINING& t) const
{
  //
  // Note: be careful of the sign for % operation
  // 
  int64_t abs_stride = (t.distance > 0 ? t.distance : -t.distance);
  int64_t lb = (t.low  - abs_stride < t.low  ? t.low  - abs_stride : t.low/*0*/);
  int64_t ub = (t.high + abs_stride > t.high ? t.high + abs_stride : t.high/*-1*/);
 
  if (/*(t.size == size) &&*/ (((t.low - ea) % abs_stride) == 0) &&