maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
105,667 Commits 23 Branches 0 Tags 2.2 GiB
Commit Graph

3 Commits

Author SHA1 Message Date
Evan Cheng 43054e6159 Re-enable branchfolding common code hoisting optimization. Fixed a liveness test bug and also taught it to update liveins. 
llvm-svn: 131241
 2011-05-12 20:30:01 +00:00
Rafael Espindola 2a09d65979 Revert 131172 as it is causing clang to miscompile itself. I will try 
to provide a reduced testcase.

llvm-svn: 131176
 2011-05-11 03:27:17 +00:00
Evan Cheng 05fc35e275 Add a late optimization to BranchFolding that hoist common instruction sequences 
at the start of basic blocks to their common predecessor. It's actually quite
common (e.g. about 50 times in JM/lencod) and has shown to be a nice code size
benefit. e.g.

        pushq   %rax
        testl   %edi, %edi
        jne     LBB0_2
## BB#1:
        xorb    %al, %al
        popq    %rdx
        ret
LBB0_2:
        xorb    %al, %al
        callq   _foo
        popq    %rdx
        ret

=>

        pushq   %rax
        xorb    %al, %al
        testl   %edi, %edi
        je      LBB0_2
## BB#1:
        callq   _foo
LBB0_2:
        popq    %rdx
        ret

rdar://9145558

llvm-svn: 131172
 2011-05-11 01:03:01 +00:00