Discussed here:
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120320.html
In preparation for adding support for named vregs we are changing the sigil for
physical registers in MIR to '$' from '%'. This will prevent name clashes of
named physical register with named vregs.
llvm-svn: 323922
As part of the unification of the debug format and the MIR format, print
MBB references as '%bb.5'.
The MIR printer prints the IR name of a MBB only for block definitions.
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)->getNumber\(\)/" << printMBBReference(*\1)/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)\.getNumber\(\)/" << printMBBReference(\1)/g'
* find . \( -name "*.txt" -o -name "*.s" -o -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#([0-9]+)/%bb.\1/g'
* grep -nr 'BB#' and fix
Differential Revision: https://reviews.llvm.org/D40422
llvm-svn: 319665
output
As part of the unification of the debug format and the MIR format,
always use `printReg` to print all kinds of registers.
Updated the tests using '_' instead of '%noreg' until we decide which
one we want to be the default one.
Differential Revision: https://reviews.llvm.org/D40421
llvm-svn: 319445
Summary:
This change allows usage of store instruction for implicit null check.
Memory Aliasing Analisys is not used and change conservatively supposes
that any store and load may access the same memory. As a result
re-ordering of store-store, store-load and load-store is prohibited.
Patch by Serguei Katkov!
Reviewers: reames, sanjoy
Reviewed By: sanjoy
Subscribers: atrick, llvm-commits
Differential Revision: https://reviews.llvm.org/D29400
llvm-svn: 294338
Summary:
This fixes an issue with MachineBlockPlacement due to a badly timed call
to `analyzeBranch` with `AllowModify` set to true. The timeline is as
follows:
1. `MachineBlockPlacement::maybeTailDuplicateBlock` calls
`TailDup.shouldTailDuplicate` on its argument, which in turn calls
`analyzeBranch` with `AllowModify` set to true.
2. This `analyzeBranch` call edits the terminator sequence of the block
based on the physical layout of the machine function, turning an
unanalyzable non-fallthrough block to a unanalyzable fallthrough
block. Normally MBP bails out of rearranging such blocks, but this
block was unanalyzable non-fallthrough (and thus rearrangeable) the
first time MBP looked at it, and so it goes ahead and decides where
it should be placed in the function.
3. When placing this block MBP fails to analyze and thus update the
block in keeping with the new physical layout.
Concretely, before (1) we have something like:
```
LBL0:
< unknown terminator op that may branch to LBL1 >
jmp LBL1
LBL1:
... A
LBL2:
... B
```
In (2), analyze branch simplifies this to
```
LBL0:
< unknown terminator op that may branch to LBL2 >
;; jmp LBL1 <- redundant jump removed
LBL1:
... A
LBL2:
... B
```
In (3), MachineBlockPlacement goes ahead with its plan of putting LBL2
after the first block since that is profitable.
```
LBL0:
< unknown terminator op that may branch to LBL2 >
;; jmp LBL1 <- redundant jump
LBL2:
... B
LBL1:
... A
```
and the program now has incorrect behavior (we no longer fall-through
from `LBL0` to `LBL1`) because MBP can no longer edit LBL0.
There are several possible solutions, but I went with removing the teeth
off of the `analyzeBranch` calls in TailDuplicator. That makes thinking
about the result of these calls easier, and breaks nothing in the lit
test suite.
I've also added some bookkeeping to the MachineBlockPlacement pass and
used that to write an assert that would have caught this.
Reviewers: chandlerc, gberry, MatzeB, iteratee
Subscribers: mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D27783
llvm-svn: 289764
Puyan Lotfi