优化技术简介—常数传播 tmp 4 =0 fo fO tmp 4 i f1 tmp 5 f1 tmp 5 tmp =2 i tmpb i
优化技术简介—常数传播 _tmp4 = 0 ; f0 = _tmp4 ; _tmp5 = 1 ; f1 = _tmp5 ; _tmp6 = 2 ; i = _tmp6 ; f0 = 0 ; f1 = 1 ; i = 2 ;
优化技术简介一代数简化 x+0 0+x Ⅹ大1= 1大 0/×=0 b & true = b b & false false b true = true b false b
优化技术简介—代数简化 x+0 = x 0+x = x x*1 = x 1*x = x 0/x = 0 x-0 = x b && true = b b && false = false b || true = true b || false = b
优化技术简介一代数简化 b=5+a+10 tmpo=5 i tmpl= tmp t a i tmp2= tmp1 +10 i tmp i tmp0=15; tmpl =a tmpo i
优化技术简介—代数简化 b = 5 + a + 10 ; _tmp0 = 5 ; _tmp1 = _tmp0 + a ; _tmp2 = _tmp1 + 10 ; b = _tmp2 ; _tmp0 = 15 ; _tmp1 = a + _tmp0 ; b = _tmp1 ;
优化技术简介—降低运算强度 a)i大2=2大=立+i <<2 b)i/2=(int)(i*0.5) c)0-1=-1 d)f*2=2.0大f=f+f e)f/2.0=f+0.5
优化技术简介—降低运算强度 a) i*2 = 2*i = i+i = i<<2 b) i/2 = (int)(i*0.5) c) 0-1 = -1 d) f*2 = 2.0 * f = f + f e) f/2.0 = f*0.5
优化技术简介一复写传播 tmp =tmpl i tmp tmpl tmp3=tmp2大 tmpl tmpl tmp5=tmp3大 tmp = tmp3i tmpl i tmp 5 = tmp tmp5 tmp 3 tmp tmp5 t tmp 4
优化技术简介—复写传播 tmp2 = tmp1 ; tmp3 = tmp2 * tmp1; tmp4 = tmp3 ; tmp5 = tmp3 * tmp2 ; c = tmp5 + tmp4 ; tmp3 = tmp1 * tmp1 ; tmp5 = tmp3 * tmp1 ; c = tmp5 + tmp3 ;