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| author | Chris Lattner <sabre@nondot.org> | 2008-05-05 23:19:45 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2008-05-05 23:19:45 +0000 |
| commit | 88c1baa50c3947026f0ee76471933775b31e2a49 (patch) | |
| tree | 17f5c5683279960f0210ed4ebd2423813a3e6293 /lib | |
| parent | ab3e747c64dc5cbf00c3e0ce5275a3bfac5e56be (diff) | |
| download | llvm-88c1baa50c3947026f0ee76471933775b31e2a49.tar.gz llvm-88c1baa50c3947026f0ee76471933775b31e2a49.tar.bz2 llvm-88c1baa50c3947026f0ee76471933775b31e2a49.tar.xz | |
add a micro optzn.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50681 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Target/X86/README.txt | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index fcbae96bee..6f6abd478d 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -1691,3 +1691,21 @@ LBB1_1: ## bb.i ... //===---------------------------------------------------------------------===// + +We compile: + +int test(int x, int y) { + return x-y-1; +} + +into (-m64): + +_test: + decl %edi + movl %edi, %eax + subl %esi, %eax + ret + +it would be better to codegen as: x+~y (notl+addl) + +//===---------------------------------------------------------------------===// |