Commit Graph

371 Commits

Author SHA1 Message Date
Sanjay Patel 0cb2ee9287 [InstSimplify] refactor related div/rem folds; NFCI
llvm-svn: 297052
2017-03-06 19:08:35 +00:00
Sanjay Patel 79a9ecbe80 [InstSimplify] remove misleading comments; NFC
Div/rem-of-0 does not cause faults/undef (not the same as div/rem-by-0).

llvm-svn: 297029
2017-03-06 16:49:35 +00:00
Sanjay Patel fe67255961 [InstSimplify] add nsw/nuw (xor X, signbit), signbit --> X
The change to InstCombine in:
https://reviews.llvm.org/D29729
...exposes this missing fold in InstSimplify, so adding this
first to avoid a regression.

llvm-svn: 295573
2017-02-18 21:59:09 +00:00
Sanjay Patel 54656ca7db [ValueTracking] emit a remark when we detect a conflicting assumption (PR31809)
This is a follow-up to D29395 where we try to be good citizens and let the user know that
we've probably gone off the rails.

This should allow us to resolve:
https://llvm.org/bugs/show_bug.cgi?id=31809

Differential Revision: https://reviews.llvm.org/D29404

llvm-svn: 294208
2017-02-06 18:26:06 +00:00
Sanjay Patel 562272536a [InstSimplify] try to eliminate icmp Pred (add nsw X, C1), C2
I was surprised to see that we're missing icmp folds based on 'add nsw' in InstCombine, 
but we should handle the InstSimplify cases first because that could make the InstCombine
code simpler.

Here are Alive-based proofs for the logic:

Name: add_neg_constant
Pre: C1 < 0 && (C2 > ((1<<(width(C1)-1)) + C1))
%a = add nsw i7 %x, C1
%b = icmp sgt %a, C2
  =>
%b = false

Name: add_pos_constant
Pre: C1 > 0 && (C2 < ((1<<(width(C1)-1)) + C1 - 1))
%a = add nsw i6 %x, C1
%b = icmp slt %a, C2
  =>
%b = false

Name: nuw
Pre: C1 u>= C2
%a = add nuw i11 %x, C1
%b = icmp ult %a, C2
  =>
%b = false

Differential Revision: https://reviews.llvm.org/D29053

llvm-svn: 292952
2017-01-24 17:03:24 +00:00
Sanjay Patel be332137fd [InstSimplify] refactor finding limits for icmp with binop; NFCI
llvm-svn: 292812
2017-01-23 18:22:26 +00:00
Marcello Maggioni 0616b5ff5c Removing potentially error-prone fallthrough. NFC
This fallthrough if other cases are added between fabs and default
could cause fabs to fall to the next case resulting in a bug.
Better getting rid of it immediately just to be sure.

llvm-svn: 292003
2017-01-14 07:28:47 +00:00
Matt Arsenault 8260666d11 InstSimplify: Refactor function to use more switches
llvm-svn: 291634
2017-01-11 00:57:54 +00:00
Matt Arsenault 1e0edbf03c InstSimplify: Eliminate fabs on known positive
llvm-svn: 291624
2017-01-11 00:33:24 +00:00
David Majnemer 63da0c238b [InstSimplify] Optimize away udivs in the presence of range metadata
We know that udiv %V, C can be optimized away to 0 if %V is ult C.

llvm-svn: 291296
2017-01-06 22:58:02 +00:00
David Majnemer 8c0e62f507 [InstSimplify] Optimize away urems in the presence of range metadata
We know that urem %V, C can be optimized away to %V if %V is ult C.

llvm-svn: 291282
2017-01-06 21:23:51 +00:00
Daniel Jasper aec2fa352f Revert @llvm.assume with operator bundles (r289755-r289757)
This creates non-linear behavior in the inliner (see more details in
r289755's commit thread).

llvm-svn: 290086
2016-12-19 08:22:17 +00:00
Hal Finkel 3ca4a6bcf1 Remove the AssumptionCache
After r289755, the AssumptionCache is no longer needed. Variables affected by
assumptions are now found by using the new operand-bundle-based scheme. This
new scheme is more computationally efficient, and also we need much less
code...

llvm-svn: 289756
2016-12-15 03:02:15 +00:00
Sanjay Patel 35289c62a8 [InstSimplify] improve function name; NFC
llvm-svn: 289332
2016-12-10 17:40:47 +00:00
Zia Ansari 394cef803a [InstSimplify] Add "X / 1.0" to SimplifyFDivInst.
Differential Revision: https://reviews.llvm.org/D27587

llvm-svn: 289153
2016-12-08 23:27:40 +00:00
Sanjay Patel 5369775a84 [InstSimplify] fixed (?) to not mutate icmps
As Eli noted in the post-commit thread for r288833, the use of
swapOperands() may not be allowed in InstSimplify, so I'm 
removing those calls here pending further review. 

The swap mutates the icmp, and there doesn't appear to be precedent
for instruction mutation in InstSimplify.

I didn't actually have any tests for those cases, so I'm adding
a few here. 

llvm-svn: 288855
2016-12-06 22:09:52 +00:00
Sanjay Patel 9b1b2de348 [InstSimplify] add folds for and-of-icmps with same operands
All of these (and a few more) are already handled by InstCombine,
but we shouldn't have to wait until then to simplify these because
they're cheap to deal with here in InstSimplify.

This is the 'and' sibling of the earlier 'or' patch:
https://reviews.llvm.org/rL288833

llvm-svn: 288841
2016-12-06 19:05:46 +00:00
Sanjay Patel d0ccdb46b9 [InstSimplify] add folds for or-of-icmps with same operands
All of these (and a few more) are already handled by InstCombine,
but we shouldn't have to wait until then to simplify these because
they're cheap to deal with here in InstSimplify.

llvm-svn: 288833
2016-12-06 18:09:37 +00:00
Sanjay Patel 9d5b5e38bb [InstSimplify] add more helper functions for SimplifyICmpInst; NFCI
llvm-svn: 288589
2016-12-03 18:03:53 +00:00
Sanjay Patel dc65a27a10 [InstSimplify] add helper functions for SimplifyICmpInst; NFCI
llvm-svn: 288588
2016-12-03 17:30:22 +00:00
Sanjay Patel 8ca30ab0c5 [InstSimplify] allow integer vector types to use computeKnownBits
Note that the non-splat lshr+lshr test folded, but that does not
work in general. Something is missing or wrong in computeKnownBits
as the non-splat shl+shl test still shows.

llvm-svn: 288005
2016-11-27 21:07:28 +00:00
Sanjoy Das 01969218a4 Simplify `x >=u x >> y` and `x >=u x udiv y`
Summary:
Extends InstSimplify to handle both `x >=u x >> y` and `x >=u x udiv y`.

This is a folloup of rL258422 and
https://github.com/rust-lang/rust/pull/30917 where llvm failed to
optimize away the bounds checking in a binary search.

Patch by Arthur Silva!

Reviewers: sanjoy

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D25941

llvm-svn: 285228
2016-10-26 19:18:43 +00:00
Sanjay Patel efd8885772 [InstSimplify] fold negation of sign-bit
0 - X --> X, if X is 0 or the minimum signed value
0 - X --> 0, if X is 0 or the minimum signed value and the sub is NSW

I noticed this pattern might be created in the backend after the change from D25485, 
so we'll want to add a similar fold for the DAG.

The use of computeKnownBits in InstSimplify may be something to investigate if the
compile time of InstSimplify is noticeable. We could replace computeKnownBits with 
specific pattern matchers or limit the recursion.

Differential Revision: https://reviews.llvm.org/D25785

llvm-svn: 284649
2016-10-19 21:23:45 +00:00
Sanjoy Das 1f7b813e2b Remove duplicated code; NFC
ICmpInst::makeConstantRange does exactly the same thing as
ConstantRange::makeExactICmpRegion.

llvm-svn: 283059
2016-10-02 00:09:57 +00:00
Sanjay Patel 220a8730fb [InstSimplify] allow or-of-icmps folds with vector splat constants
llvm-svn: 282592
2016-09-28 14:27:21 +00:00
Sanjay Patel 1b312ad42d [InstSimplify] allow and-of-icmps folds with vector splat constants
llvm-svn: 282590
2016-09-28 13:53:13 +00:00
Sanjay Patel b2332e1931 move variables closer to their uses; add FIXMEs; NFC
llvm-svn: 281972
2016-09-20 14:36:14 +00:00
Andrea Di Biagio bff3fd6700 Simplify code a bit. No functional change intended.
We don't need to call `GetCompareTy(LHS)' every single time true or false is
returned from function SimplifyFCmpInst as suggested by Sanjay in review D24142.

llvm-svn: 280491
2016-09-02 15:55:25 +00:00
Andrea Di Biagio 805815f407 [instsimplify] Fix incorrect folding of an ordered fcmp with a vector of all NaN.
This patch fixes a crash caused by an incorrect folding of an ordered comparison
between a packed floating point vector and a splat vector of NaN.

An ordered comparison between a vector and a constant vector of NaN, should
always be folded into a constant vector where each element is i1 false.

Since revision 266175, SimplifyFCmpInst folds the ordered fcmp into a scalar
'false'. Later on, this would cause an assertion failure, since the value type
of the folded value doesn't match the expected value type of the uses of the
original instruction: "Assertion failed: New->getType() == getType() &&
"replaceAllUses of value with new value of different type!".

This patch fixes the issue and adds a test case to the already existing test
InstSimplify/floating-point-compares.ll.

Differential Revision: https://reviews.llvm.org/D24143

llvm-svn: 280488
2016-09-02 14:47:43 +00:00
Sanjay Patel 6946e2ade3 [InstSimplify] allow icmp with constant folds for splat vectors, part 2
Completes the m_APInt changes for simplifyICmpWithConstant().

Other commits in this series:
https://reviews.llvm.org/rL279492
https://reviews.llvm.org/rL279530
https://reviews.llvm.org/rL279534
https://reviews.llvm.org/rL279538

llvm-svn: 279543
2016-08-23 18:00:51 +00:00
Sanjay Patel 200e3cbfb0 [InstSimplify] allow icmp with constant folds for splat vectors, part 1
llvm-svn: 279538
2016-08-23 17:30:56 +00:00
Sanjay Patel 67bde28627 [InstSimplify] add helper function for SimplifyICmpInst(); NFCI
And add a FIXME because the helper excludes folds for vectors. It's
not clear yet how many of these are actually testable (and therefore
necessary?) because later analysis uses computeKnownBits and other
methods to catch many of these cases.

llvm-svn: 279492
2016-08-22 23:12:02 +00:00
Justin Bogner b03fd12cef Replace "fallthrough" comments with LLVM_FALLTHROUGH
This is a mechanical change of comments in switches like fallthrough,
fall-through, or fall-thru to use the LLVM_FALLTHROUGH macro instead.

llvm-svn: 278902
2016-08-17 05:10:15 +00:00
David Majnemer 5c5df6283a [InstSimplify] Fold gep (gep V, C), (xor V, -1) to C-1
llvm-svn: 278779
2016-08-16 06:13:46 +00:00
David Majnemer 0a16c22846 Use range algorithms instead of unpacking begin/end
No functionality change is intended.

llvm-svn: 278417
2016-08-11 21:15:00 +00:00
David Majnemer d150137f64 [InstSimplify] Fold gep (gep V, C), (sub 0, V) to C
llvm-svn: 277952
2016-08-07 07:58:12 +00:00
David Majnemer dc8767a49a [InstSimplify] Try hard to simplify pointer comparisons
Simplify ptrtoint comparisons involving operands with different source
types.

llvm-svn: 277951
2016-08-07 07:58:10 +00:00
Sanjay Patel bcaf6f39dd [InstCombine] use m_APInt to allow icmp eq (op X, Y), C folds for splat constant vectors
I'm removing a misplaced pair of more specific folds from InstCombine in this patch as well,
so we know where those folds are happening in InstSimplify.

llvm-svn: 277738
2016-08-04 17:48:04 +00:00
David Majnemer 909793fa63 Reinstate "[CloneFunction] Don't remove side effecting calls"
This reinstates r277611 + r277614 and reverts r277642.  A cast_or_null
should have been a dyn_cast_or_null.

llvm-svn: 277691
2016-08-04 04:24:02 +00:00
Reid Kleckner a6be60871f Revert "[CloneFunction] Don't remove side effecting calls"
This reverts commit r277611 and the followup r277614.

Bootstrap builds and chromium builds are crashing during inlining after
this change.

llvm-svn: 277642
2016-08-03 20:01:01 +00:00
David Majnemer fad0490869 [CloneFunction] Don't remove side effecting calls
We were able to figure out that the result of a call is some constant.
While propagating that fact, we added the constant to the value map.
This is problematic because it results in us losing the call site when
processing the value map.

This fixes PR28802.

llvm-svn: 277611
2016-08-03 17:12:47 +00:00
David Majnemer 6774d612d4 [InstSimplify] Cast folding can be made more generic
Use isEliminableCastPair to determine if a pair of casts are foldable.

llvm-svn: 276777
2016-07-26 17:58:05 +00:00
David Majnemer a90a621d1e Reapply: [InstSimplify] Add support for bitcasts"
This reverts commit r276700 and reapplies r276698.
The relevant clang tests have been updated.

llvm-svn: 276727
2016-07-26 05:52:29 +00:00
David Majnemer 6e06b577cc Revert "[InstSimplify] Add support for bitcasts"
This reverts commit r276698.  Clang has tests which rely on the
optimizer :(

llvm-svn: 276700
2016-07-25 22:24:59 +00:00
David Majnemer 62611fd3f7 [InstSimplify] Add support for bitcasts
BitCasts of BitCasts can be folded away as can BitCasts which don't
change the type of the operand.

llvm-svn: 276698
2016-07-25 22:04:58 +00:00
David Majnemer 126de5d4b4 [InstSimplify] Fold trunc([zs]ext(%V)) -> %V
Truncates can completely cancel out a zext or sext instruction.

llvm-svn: 276604
2016-07-25 03:39:21 +00:00
Sanjay Patel e9fc79bb13 [InstSimplify] don't crash handling a pointer or aggregate type
llvm-svn: 276345
2016-07-21 21:56:00 +00:00
Sanjay Patel a3bfb4e313 [InstSimplify] recognize trunc + icmp sgt/slt variants of select simplifications (PR28466)
rL245171 exposed a hole in InstSimplify that manifested in a strange way in PR28466:
https://llvm.org/bugs/show_bug.cgi?id=28466

It's possible to use trunc + icmp sgt/slt in place of an and + icmp eq/ne, so we need to
recognize that pattern to eliminate selects that are choosing between some value and some
bitmasked version of that value.

Note that there is significant room for improvement (refactoring) and enhancement (more
patterns, possibly in InstCombine rather than here).

Differential Revision: https://reviews.llvm.org/D22537

llvm-svn: 276341
2016-07-21 21:26:45 +00:00
Sanjay Patel 5f3c70307d [InstSimplify][InstCombine] don't crash when folding vector selects of icmp
Differential Revision: https://reviews.llvm.org/D22602

llvm-svn: 276209
2016-07-20 23:40:01 +00:00
Sanjay Patel 5f5eb58eb5 refactor SimplifySelectInst; NFCI
llvm-svn: 275911
2016-07-18 20:56:53 +00:00