Commit Graph

7 Commits

Author SHA1 Message Date
Evan Cheng
977679d603 Added a late machine instruction copy propagation pass. This catches
opportunities that only present themselves after late optimizations
such as tail duplication .e.g.
## BB#1:
        movl    %eax, %ecx
        movl    %ecx, %eax
        ret

The register allocator also leaves some of them around (due to false
dep between copies from phi-elimination, etc.)

This required some changes in codegen passes. Post-ra scheduler and the
pseudo-instruction expansion passes have been moved after branch folding
and tail merging. They were before branch folding before because it did
not always update block livein's. That's fixed now. The pass change makes
independently since we want to properly schedule instructions after
branch folding / tail duplication.

rdar://10428165
rdar://10640363



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147716 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-07 03:02:36 +00:00
Jim Grosbach
dd11988c99 Properly pseudo-ize the ARM LDMIA_RET instruction. This has the nice side-
effect that we get proper instruction printing using the "pop" mnemonic for it.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127502 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-11 22:51:41 +00:00
Cameron Zwarich
56e3793acf Eliminate the unused CodeGenPrepare option to split critical edges.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126825 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02 03:31:46 +00:00
Jakob Stoklund Olesen
b53afc6a12 Explicitly disable CGP critical edge splitting for this test so it won't break
by reenabling it temporarily.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114858 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-27 18:43:43 +00:00
Jakob Stoklund Olesen
4c2c865a51 Don't depend on basic block numbering.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114857 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-27 18:43:40 +00:00
Evan Cheng
fff606d7b2 Enable code placement optimization pass for ARM.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114746 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-24 19:07:23 +00:00
Evan Cheng
97b9b97853 PHI elimination should not break back edge. It can cause some significant code placement issues. rdar://8263994
good:
LBB0_2:
  mov     r2, r0
  . . .
  mov     r1, r2
  bne     LBB0_2

bad:
LBB0_2:
  mov     r2, r0
  . . .
@ BB#3:
  mov     r1, r2
  b       LBB0_2


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111221 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-17 01:20:36 +00:00