The shl instruction is used to represent multiplication by a constant
power of two as well as bitwise left shifts. Some InstCombine
transformations would turn an shl instruction into a bit mask operation,
making it difficult for later analysis passes to recognize the
constsnt multiplication.
Disable those shl transformations, deferring them to DAGCombine time.
An 'shl X, C' instruction is now treated mostly the same was as 'mul X, C'.
These transformations are deferred:
(X >>? C) << C --> X & (-1 << C) (When X >> C has multiple uses)
(X >>? C1) << C2 --> X << (C2-C1) & (-1 << C2) (When C2 > C1)
(X >>? C1) << C2 --> X >>? (C1-C2) & (-1 << C2) (When C1 > C2)
The corresponding exact transformations are preserved, just like
div-exact + mul:
(X >>?,exact C) << C --> X
(X >>?,exact C1) << C2 --> X << (C2-C1)
(X >>?,exact C1) << C2 --> X >>?,exact (C1-C2)
The disabled transformations could also prevent the instruction selector
from recognizing rotate patterns in hash functions and cryptographic
primitives. I have a test case for that, but it is too fragile.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155136 91177308-0d34-0410-b5e6-96231b3b80d8
- Work in progress, this is mostly important because it lets us incrementally migrate the remaining documentation.
- Lots of styling, editing, and integration work yet to come…
- PR12589
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155133 91177308-0d34-0410-b5e6-96231b3b80d8
symbolicated. These have and operand type of TYPE_RELv which was not handled
as isBranch in translateImmediate() in X86Disassembler.cpp. rdar://11268426
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155074 91177308-0d34-0410-b5e6-96231b3b80d8
commits have had several major issues pointed out in review, and those
issues are not being addressed in a timely fashion. Furthermore, this
was all committed leading up to the v3.1 branch, and we don't need piles
of code with outstanding issues in the branch.
It is possible that not all of these commits were necessary to revert to
get us back to a green state, but I'm going to let the Hexagon
maintainer sort that out. They can recommit, in order, after addressing
the feedback.
Reverted commits, with some notes:
Primary commit r154616: HexagonPacketizer
- There are lots of review comments here. This is the primary reason
for reverting. In particular, it introduced large amount of warnings
due to a bad construct in tablegen.
- Follow-up commits that should be folded back into this when
reposting:
- r154622: CMake fixes
- r154660: Fix numerous build warnings in release builds.
- Please don't resubmit this until the three commits above are
included, and the issues in review addressed.
Primary commit r154695: Pass to replace transfer/copy ...
- Reverted to minimize merge conflicts. I'm not aware of specific
issues with this patch.
Primary commit r154703: New Value Jump.
- Primarily reverted due to merge conflicts.
- Follow-up commits that should be folded back into this when
reposting:
- r154703: Remove iostream usage
- r154758: Fix CMake builds
- r154759: Fix build warnings in release builds
- Please incorporate these fixes and and review feedback before
resubmitting.
Primary commit r154829: Hexagon V5 (floating point) support.
- Primarily reverted due to merge conflicts.
- Follow-up commits that should be folded back into this when
reposting:
- r154841: Remove unused variable (fixing build warnings)
There are also accompanying Clang commits that will be reverted for
consistency.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155047 91177308-0d34-0410-b5e6-96231b3b80d8
DenseMap's hash function uses slightly more entropy and reduces hash collisions
significantly. I also experimented with Hashing.h, but it didn't gave a lot of
improvement while being much more expensive to compute.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154996 91177308-0d34-0410-b5e6-96231b3b80d8
If the loop contains invoke instructions, whose unwind edge escapes the loop,
then don't try to unswitch the loop. Doing so may cause the unwind edge to be
split, which not only is non-trivial but doesn't preserve loop simplify
information.
Fixes PR12573
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154987 91177308-0d34-0410-b5e6-96231b3b80d8
This introduces a threshold of 200 IV Users, which is very
conservative but should be sufficient to avoid serious compile time
sink or stack overflow. The llvm test-suite with LTO never exceeds 190
users per loop.
The bug doesn't relate to a specific type of loop. Checking in an
arbitrary giant loop as a unit test would be silly.
Fixes rdar://11262507.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154983 91177308-0d34-0410-b5e6-96231b3b80d8
