Commit Graph

7 Commits

Author SHA1 Message Date
Evan Cheng 76fa6e6a8f New entry.
llvm-svn: 78968
2009-08-14 00:16:47 +00:00
Evan Cheng b64ec07ea6 This is done.
llvm-svn: 78399
2009-08-07 19:34:52 +00:00
Evan Cheng f0237b1aa6 Use 16-bit tMOVgpr2gpr instead of tMOVr to copy GPR registers in Thumb2 mode.
llvm-svn: 78398
2009-08-07 19:34:35 +00:00
Evan Cheng b972e5633f It turns out most of the thumb2 instructions are not allowed to touch SP. The semantics of such instructions are unpredictable. We have just been lucky that tests have been passing.
This patch takes pain to ensure all the PEI lowering code does the right thing when lowering frame indices, insert code to manipulate stack pointers, etc. It's also custom lowering dynamic stack alloc into pseudo instructions so we can insert the right instructions at scheduling time.

This fixes PR4659 and PR4682.

llvm-svn: 78361
2009-08-07 00:34:42 +00:00
Evan Cheng 97f7dfb862 These are done.
llvm-svn: 77949
2009-08-03 04:08:36 +00:00
Evan Cheng f3a1fce8ae Change Thumb2 jumptable codegen to one that uses two level jumps:
Before:
      adr r12, #LJTI3_0_0
      ldr pc, [r12, +r0, lsl #2]
LJTI3_0_0:
      .long    LBB3_24
      .long    LBB3_30
      .long    LBB3_31
      .long    LBB3_32

After:
      adr r12, #LJTI3_0_0
      add pc, r12, +r0, lsl #2
LJTI3_0_0:
      b.w    LBB3_24
      b.w    LBB3_30
      b.w    LBB3_31
      b.w    LBB3_32

This has several advantages.
1. This will make it easier to optimize this to a TBB / TBH instruction +
   (smaller) table.
2. This eliminate the need for ugly asm printer hack to force the address
   into thumb addresses (bit 0 is one).
3. Same codegen for pic and non-pic.
4. This eliminate the need to align the table so constantpool island pass
   won't have to over-estimate the size.

Based on my calculation, the later is probably slightly faster as well since
ldr pc with shifter address is very slow. That is, it should be a win as long
as the HW implementation can do a reasonable job of branch predict the second
branch.

llvm-svn: 77024
2009-07-25 00:33:29 +00:00
Evan Cheng b61e3a83ee Add a todo.
llvm-svn: 74976
2009-07-08 00:05:05 +00:00