Commit Graph

12 Commits

Author SHA1 Message Date
Sander de Smalen f28e1128d9 Relanding r368987 [AArch64] Change location of frame-record within callee-save area.
Changes:
There was a condition for `!NeedsFrameRecord` missing in the assert. The
assert in question has changed to:

+    assert((!RPI.isPaired() || !NeedsFrameRecord || RPI.Reg2 != AArch64::FP ||
+            RPI.Reg1 == AArch64::LR) &&
+           "FrameRecord must be allocated together with LR");

This addresses PR43016.

llvm-svn: 369122
2019-08-16 15:42:28 +00:00
Nico Weber ee96499a42 Revert r368987, it caused PR43016.
llvm-svn: 369080
2019-08-16 02:21:21 +00:00
Sander de Smalen 643adb5576 [AArch64] Change location of frame-record within callee-save area.
This patch changes the location of the frame-record (FP, LR) to the 
bottom of the callee-saved area. According to the AAPCS the location of
the frame-record within the stackframe is unspecified (section 5.2.3 The 
Frame Pointer), so the compiler should be free to choose a different
location.

The reason for changing the location of the frame-record is to prepare
the frame for allocating an SVE area below the callee-saves. This way the 
compiler can use the VL-scaled addressing modes to directly access SVE 
objects from the frame-pointer.

            :                :   
        | stack |        | stack |
        |  args |        |  args |
        +-------+        +-------+
        |  x30  |        |  x19  |
        |  x29  |        |  x20  |
  FP -> |- - - -|        |  x21  |
        |  x19  |   ==>  |  x22  |
        |  x20  |        |- - - -|
        |  x21  |        |  x30  |
        |  x22  |        |  x29  |
        +-------+        +-------+ <- FP
        |///////|        |///////|         // realignment gap 
        |- - - -|        |- - - -|
        |spills/|        |spills/|
        | locals|        | locals|
  SP -> +-------+        +-------+ <- SP

Things to point out:
- The algorithm to find a paired register should be prevented from
  accidentally pairing some callee-saved register with LR that is not 
  FP, since they should always be paired together when the frame
  has a frame-record.
- For Darwin platforms the location of the frame-record is unchanged,
  since the unwind encoding does not allow for encoding this position
  dynamically and other tools currently depend on the former layout. 

Reviewers: efriedma, rovka, rengolin, thegameg, greened, t.p.northover

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D65653

llvm-svn: 368987
2019-08-15 10:34:16 +00:00
Nikita Popov 9a4453592b [DAGCombine] Fold (x & ~y) | y patterns
Fold (x & ~y) | y and it's four commuted variants to x | y. This pattern
can in particular appear when a vselect c, x, -1 is expanded to
(x & ~c) | (-1 & c) and combined to (x & ~c) | c.

This change has some overlap with D59066, which avoids creating a
vselect of this form in the first place during uaddsat expansion.

Differential Revision: https://reviews.llvm.org/D59174

llvm-svn: 356333
2019-03-17 15:45:38 +00:00
Sanjay Patel c6441c8547 [DAGCombiner] use root SDLoc for all nodes created by logic fold
If this is not a valid way to assign an SDLoc, then we get this
wrong all over SDAG.

I don't know enough about the SDAG to explain this. IIUC, theoretically,
debug info is not supposed to affect codegen. But here it has clearly
affected 3 different targets, and the x86 change is an actual improvement.

llvm-svn: 348552
2018-12-07 00:01:57 +00:00
Sander de Smalen 6cab60fa06 Extend hasStoreToStackSlot with list of FI accesses.
For instructions that spill/fill to and from multiple frame-indices
in a single instruction, hasStoreToStackSlot and hasLoadFromStackSlot
should return an array of accesses, rather than just the first encounter
of such an access.

This better describes FI accesses for AArch64 (paired) LDP/STP
instructions.

Reviewers: t.p.northover, gberry, thegameg, rengolin, javed.absar, MatzeB

Reviewed By: MatzeB

Differential Revision: https://reviews.llvm.org/D51537

llvm-svn: 341301
2018-09-03 09:15:58 +00:00
Roman Lebedev 0412c90236 [DAGCombine][NFC] Masked merge unfolding: comment: some tests are non-canonical
As requested in https://reviews.llvm.org/D46494#inline-407282

llvm-svn: 331650
2018-05-07 16:42:47 +00:00
Roman Lebedev a3b0b59f54 [DAGCombiner] Masked merge: don't touch "not" xor's.
Summary:
Split off form D46031.

It seems we don't want to transform the pattern if the `xor`'s are actually `not`'s.
In vector case, this breaks `andnpd` / `vandnps` patterns.

That being said, we may want to re-visit this `not` handling, maybe in D46073.

Reviewers: spatel, craig.topper, javed.absar

Reviewed By: spatel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D46492

llvm-svn: 331595
2018-05-05 15:45:40 +00:00
Roman Lebedev cfa9e58ccf [X86][AArch64][NFC] Finish adding 'bad' tests for masked merge unfolding with constants.
I have initially committed basic tests in, rL330771,
but then quickly discovered that there are a few more
interesting patterns.

llvm-svn: 330819
2018-04-25 12:48:23 +00:00
Roman Lebedev 54df09e8fe [X86][AArch64][NFC] Add tests for masked merge unfolding with %y = const
The fold was added in D45733.

This appears to be a regression.

llvm-svn: 330771
2018-04-24 21:23:22 +00:00
Roman Lebedev 95c6eaf530 [DAGCombiner] Unfold scalar masked merge if profitable
Summary:
This is [[ https://bugs.llvm.org/show_bug.cgi?id=37104 | PR37104 ]].

[[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]] will introduce an IR canonicalization that is likely bad for the end assembly.
Previously, `andl`+`andn`/`andps`+`andnps` / `bic`/`bsl` would be generated. (see `@out`)
Now, they would no longer be generated  (see `@in`).
So we need to make sure that they are still generated.

If the mask is constant, we do nothing. InstCombine should have unfolded it.
Else, i use `hasAndNot()` TLI hook.

For now, only handle scalars.

https://rise4fun.com/Alive/bO6

----

I *really* don't like the code i wrote in `DAGCombiner::unfoldMaskedMerge()`.
It is super fragile. Is there something like IR Pattern Matchers for this?

Reviewers: spatel, craig.topper, RKSimon, javed.absar

Reviewed By: spatel

Subscribers: andreadb, courbet, kristof.beyls, javed.absar, rengolin, nemanjai, llvm-commits

Differential Revision: https://reviews.llvm.org/D45733

llvm-svn: 330646
2018-04-23 20:38:49 +00:00
Roman Lebedev bf18cc56d3 [X86][AArch64][NFC] Add tests for masked merge unfolding
Summary:
This is [[ https://bugs.llvm.org/show_bug.cgi?id=37104 | PR37104 ]].

[[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]] will introduce an IR canonicalization that is likely bad for the end assembly.
Previously, `andl`+`andn`/`andps`+`andnps` / `bic`/`bsl` would be generated. (see `@out`)
Now, they would no longer be generated  (see `@in`).
I'm guessing `llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp` should be able to unfold this.

Reviewers: spatel, craig.topper, RKSimon, javed.absar

Reviewed By: spatel

Subscribers: nemanjai, rengolin, javed.absar, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D45563

llvm-svn: 330645
2018-04-23 20:38:42 +00:00