优化技术简介一常数传播 tmp4 =0; f0=0; f0 tmp4 i f1=1; tmp5 1; 1=2: f1 tmp5 i tmp6 =2 i=tmp6;
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=x 0+x= X X*1= X 1*x=X 0/x=0 X-0=X b &true =b b &falsefalse 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; _tmp0=5; _tmp1 tmpo a i tmp2 tmp1 10 b =tmp2 _tmp0=15; tmpl a tmpo
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 ;
优化技术简介一降低运算强度 a)i*2=2*i=i+i=i<<2 b)i/2=(int)(i*0.5) 0)0-1=-1 d)f*2=2.0*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 tmp2 tmpl tmp3 tmpl tmp3 tmp2* tmpl; tmpl tmp5 tmp3* tmp4 =tmp3 tmpl tmp5 tmp3* c tmp5 tmp3 tmp2 c tmp5 tmp4
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 ;