6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-08-17 21:29:20 +00:00
Code Issues Projects Releases Wiki Activity

add a note

Browse Source 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26513 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-03-04 01:19:34 +00:00
parent 8df346b4e8
commit b27b69f283
1 changed files with 15 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
lib/Target/README.txt
View File

@ -86,3 +86,18 @@ int f(int a, int b){ return a * a + 2 * a * b + b * b; }
into:
int f(int a, int b) { return a * (a + 2 * b) + b * b; }
to eliminate a multiply.
//===---------------------------------------------------------------------===//
On targets with expensive 64-bit multiply, we could LSR this:
for (i = ...; ++i) {
x = 1ULL << i;
into:
long long tmp = 1;
for (i = ...; ++i, tmp+=tmp)
x = tmp;
This would be a win on ppc32, but not x86 or ppc64.